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Organic foods: Are they safer? More nutritious?

Discover the difference between organic foods and their traditionally grown counterparts when it comes to nutrition, safety and price.

Once found only in health food stores, organic food is now a common feature at most grocery stores. And that's made a bit of a problem in the produce aisle.

For example, you can pick an apple grown with usual (conventional) methods. Or you can pick one that's organic. Both apples are firm, shiny and red. They both provide vitamins and fiber. And neither apple has fat, salt or cholesterol. Which should you choose? Get the facts before you shop.

What is organic farming?

The word "organic" means the way farmers grow and process farming (agricultural) products. These products include fruits, vegetables, grains, dairy products such as milk and cheese, and meat. Organic farming practices are designed to meet the following goals:

• Improve soil and water quality
• Cut pollution
• Provide safe, healthy places for farm animals (livestock) to live
• Enable natural farm animals' behavior
• Promote a self-sustaining cycle of resources on a farm

Materials or methods not allowed in organic farming include:

• Artificial (synthetic) fertilizers to add nutrients to the soil
• Sewage sludge as fertilizer
• Most synthetic pesticides for pest control
• Using radiation (irradiation) to preserve food or to get rid of disease or pests
• Using genetic technology to change the genetic makeup (genetic engineering) of crops, which can improve disease or pest resistance, or to improve crop harvests
• Antibiotics or growth hormones for farm animals (livestock)

Organic crop farming materials or practices may include:

• Plant waste left on fields (green manure), farm animals' manure or compost to improve soil quality
• Plant rotation to keep soil quality and to stop cycles of pests or disease
• Cover crops that prevent wearing away of soil (erosion) when sections of land aren't in use and to plow into soil for improving soil quality
• Mulch to control weeds
• Insects or insect traps to control pests
• Certain natural pesticides and a few synthetic pesticides approved for organic farming, used rarely and only as a last choice and coordinated with a USDA organic certifying agent

Organic farming practices for farm animals (livestock) include:

• Healthy living conditions and access to the outdoors
• Pasture feeding for at least 30% of farm animals' nutritional needs during grazing season
• Organic food for animals
• Shots to protect against disease (vaccinations)

Organic or not? Check the label

The U.S. Department of Agriculture (USDA) has set up an organic certification program that requires all organic food to meet strict government standards. These standards control how such food is grown, handled and processed.

Any product labeled as organic on the product description or packaging must be USDA certified. If it's certified, the producer may also use an official USDA Organic seal.

The USDA says producers who sell less than $5,000 a year in organic food don't need to be certified. These producers must follow the guidelines for organic food production. But they don't need to go through the certification process. They can label their products as organic. But they can't use the official USDA Organic seal.

Products certified 95 percent or more organic may display this USDA seal.

The USDA guidelines describe organic foods on product labels as:

• 100% organic. This label is used on certified organic fruits, vegetables, eggs, meat or other foods that have one ingredient. It may also be used on food items with many ingredients if all the items are certified organic, except for salt and water. These may have a USDA seal.
• Organic. If a food with many ingredients is labeled organic, at least 95% of the ingredients are certified organic, except for salt and water. The items that aren't organic must be from a USDA list of approved additional ingredients. These also may have a USDA seal.
• Made with organic. If a product with many ingredients has at least 70% certified organic ingredients, it may have a "made with organic" ingredients label. For example, a breakfast cereal might be labeled "made with organic oats." The ingredient list must show what items are organic. These products can't carry a USDA seal.
• Organic ingredients. If a product has some organic ingredients but less than 70% of the ingredients are certified organic , the product can't be labeled as organic. It also can't carry a USDA seal. The ingredient list can show which ingredients are organic.

Does 'organic' mean the same thing as 'natural'?

No, "natural" and "organic" are different. Usually, "natural" on a food label means that the product has no artificial colors, flavors or preservatives. "Natural" on a label doesn't have to do with the methods or materials used to grow the food ingredients.

Also be careful not to mix up other common food labels with organic labels. For example, certified organic beef guidelines include pasture access during at least 120 days of grazing season and no growth hormones. But the labels "free-range" or "hormone-free" don't mean a farmer followed all guidelines for organic certification.

Organic food: Is it safer or more nutritious?

Some data shows possible health benefits of organic foods when compared with foods grown using the usual (conventional) process. These studies have shown differences in the food. But there is limited information to prove how these differences can give potential overall health benefits.

Potential benefits include the following:

• Nutrients. Studies have shown small to moderate increases in some nutrients in organic produce. Organic produce may have more of certain antioxidants and types of flavonoids, which have antioxidant properties.
• Omega-3 fatty acids. The feeding requirements for organic farm animals (livestock) usually cause higher levels of omega-3 fatty acids. These include feeding cattle grass and alfalfa. Omega-3 fatty acids — a kind of fat — are more heart healthy than other fats. These higher omega-3 fatty acids are found in organic meats, dairy and eggs.
• Toxic metal. Cadmium is a toxic chemical naturally found in soils and absorbed by plants. Studies have shown much lower cadmium levels in organic grains, but not fruits and vegetables, when compared with crops grown using usual (conventional) methods. The lower cadmium levels in organic grains may be related to the ban on synthetic fertilizers in organic farming.
• Pesticide residue. Compared with produce grown using usual (conventional) methods, organically grown produce has lower levels of pesticide residue. The safety rules for the highest levels of residue allowed on conventional produce have changed. In many cases, the levels have been lowered. Organic produce may have residue because of pesticides approved for organic farming or because of airborne pesticides from conventional farms.
• Bacteria. Meats produced using usual (conventional) methods may have higher amounts of dangerous types of bacteria that may not be able to be treated with antibiotics. The overall risk of contamination of organic foods with bacteria is the same as conventional foods.

Are there downsides to buying organic?

One common concern with organic food is cost. Organic foods often cost more than similar foods grown using usual (conventional) methods. Higher prices are due, in part, to more costly ways of farming.

Food safety tips

Whether you go totally organic or choose to mix conventional and organic foods, keep these tips in mind:

• Choose a variety of foods from a mix of sources. You'll get a better variety of nutrients and lower your chance of exposure to a single pesticide.
• Buy fruits and vegetables in season when you can. To get the freshest produce, ask your grocer what is in season. Or buy food from your local farmers market.
• Read food labels carefully. Just because a product says it's organic or has organic ingredients doesn't mean it's a healthier choice. Some organic products may still be high in sugar, salt, fat or calories.
• Wash and scrub fresh fruits and vegetables well under running water. Washing helps remove dirt, germs and chemical traces from fruit and vegetable surfaces. But you can't remove all pesticide traces by washing. Throwing away the outer leaves of leafy vegetables can lessen contaminants. Peeling fruits and vegetables can remove contaminants but may also cut nutrients.

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• Organic production and handling standards. U.S. Department of Agriculture. https://www.ams.usda.gov/publications/content/organic-production-handling-standards. Accessed March 30, 2022.
• Introduction to organic practices. U.S. Department of Agriculture. https://www.ams.usda.gov/publications/content/introduction-organic-practices. Accessed March 30, 2022.
• Organic labeling at farmers markets. U.S. Department of Agriculture. https://www.ams.usda.gov/publications/content/organic-labeling-farmers-markets. Accessed March 30, 2022.
• Labeling organic products. U.S. Department of Agriculture. https://www.ams.usda.gov/publications/content/labeling-organic-products. Accessed March 30, 2022.
• Use of the term natural on food labeling. U.S. Food and Drug Administration. https://www.fda.gov/food/food-labeling-nutrition/use-term-natural-food-labeling. Accessed March 30, 2022.
• Demory-Luce D, et al. Organic foods and children. https://www.uptodate.com/contents/search. Accessed March 30, 2022.
• Pesticides and food: Healthy, sensible food practices. U.S. Environmental Protection Agency. https://www.epa.gov/safepestcontrol/pesticides-and-food-healthy-sensible-food-practices. Accessed March 30, 2022.
• Vegetable and pulses outlook: November 2021. U.S. Department of Agriculture. https://www.ers.usda.gov/publications/pub-details/?pubid=102664. Accessed March 30, 2022.
• Changes to the nutrition facts label. U.S. Food and Drug Administration. https://www.fda.gov/food/food-labeling-nutrition/changes-nutrition-facts-label. Accessed March 30, 2022.
• Rahman SME, et al. Consumer preference, quality and safety of organic and conventional fresh fruits, vegetables, and cereals. Foods. 2021; doi:10.3390/foods10010105.
• Brantsaeter AL, et al. Organic food in the diet: Exposure and health implications. Annual Review of Public Health. 2017; doi:10.1146/annurev-publhealth-031816-044437.
• Vigar V, et al. A systematic review of organic versus conventional food consumption: Is there a measurable benefit on human health? Nutrients. 2019; doi:10.3390/nu12010007.
• Mie A, et al. Human health implications of organic food and organic agriculture: A comprehensive review. Environmental Health. 2017; doi:10.1186/s12940-017-0315-4.
• Innes GK, et al. Contamination of retail meat samples with multidrug-resistant organisms in relation to organic and conventional production and processing: A cross-sectional analysis of data from the United States National Antimicrobial Resistance Monitoring System, 2012-2017. Environmental Health Perspectives. 2021; doi:10.1289/EHP7327.

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• Healthy Lifestyle
• Organic foods Are they safer More nutritious

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Organic Foods

Are organic foods healthier and safer? Learn more in our easy-to-understand videos on the latest research.

You may be surprised to learn that a review of hundreds of studies found that organic foods don’t seem to have significantly more vitamins and minerals. They do, however, appear to have more nontraditional nutrients, like polyphenol antioxidants , perhaps because conventionally grown plants given high-dose synthetic nitrogen fertilizers may divert more resources to growth rather than defense. This may be why organic berries, for example, appear to suppress cancer growth better than conventional berries in vitro.

Based on its elevated antioxidant levels, organic produce may be considered 20 to 40 percent healthier, the equivalent of adding one or two servings’ worth to a five-a-day regimen. But people don’t just buy organic foods because they’re healthier—what about safety?

Conventional produce appears to have twice the levels of cadmium, one of three toxic heavy metals in the food supply, along with mercury and lead. What about pesticide residues? Buying organic foods may reduce your exposure to pesticides, but not eliminate them entirely. Pesticide residues have reportedly been detected in 11 percent of organic crop samples due to accidental or fraudulent use, cross-contamination from neighboring nonorganic fields, or the lingering presence of persistent pollutants like DDT in the soil.

What about organic meat , eggs , and dairy ? The USDA organic standards don’t allow these animals to be fed or injected with antibiotics or steroids. All foods of animal origin—organic or not—naturally contain sex steroid hormones, though, such as estrogen, but the hormones naturally found even in organic cow’s milk may play a role in acne , diminished male reproductive potential , and premature puberty . And, in a comparison between meat from animals raised conventionally versus organically, all conventional chicken samples were contaminated with multidrug-resistant bacteria, but the majority of organic samples were, too.

For substantiation of any statements of fact from the peer-reviewed medical literature, please see the associated videos below.

Image Credit: Jessica Spengler / Flickr. This image has been modified.

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Diet and Climate Change: Cooking Up a Storm

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If we increased our consumption of conventionally-produced fruits and vegetables, how much cancer would be prevented versus how much cancer might be caused by the additional pesticide exposure?

Test tube studies show advantages of organic produce, such as better cancer cell growth suppression, but what about in people, not Petri dishes?

Commercial fruit and vegetable washes fail to work better than tap water, but there is a cheap do-it-yourself solution that may completely eliminate certain pesticide residues.

Organic food consumption appears to reduce exposure to pesticide residues and antibiotic-resistant bacteria.

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How Many Cancers Have Been Caused by Arsenic-Laced Chicken?

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Norovirus Food Poisoning from Pesticides

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Does the hormonal stimulation of human prostate cancer cells by cow milk in a petri dish translate out clinically in studies of human populations?

The level of multidrug antibiotic-resistant bacteria contamination is compared between meat from animals raised conventionally, and certified organic meat from animals raised without being fed antibiotics.

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President’s Cancer Panel Report on Environmental Risk

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The effects of organic food on human health: a systematic review and meta-analysis of population-based studies

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Bibo Jiang, Jinzhu Pang, Junan Li, Lijuan Mi, Dongmei Ru, Jingxi Feng, Xiaoxu Li, Ai Zhao, Li Cai, The effects of organic food on human health: a systematic review and meta-analysis of population-based studies, Nutrition Reviews , 2023;, nuad124, https://doi.org/10.1093/nutrit/nuad124

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Although the nutritional composition of organic food has been thoroughly researched, there is a dearth of published data relating to its impact on human health.

This systematic review aimed to examine the association between organic food intake and health effects, including changes in in vivo biomarkers, disease prevalence, and functional changes.

PubMed, EMBASE, Web of Science, the Cochrane Library, and ClinicalTrials.gov were searched from inception through Nov 13, 2022.

Both observational and interventional studies conducted in human populations were included, and association between level of organic food intake and each outcome was quantified as “no association,” “inconsistent,” “beneficial correlation/harmful correlation,” or “insufficient”. For outcomes with sufficient data reported by at least 3 studies, meta-analyses were conducted, using random-effects models to calculate standardized mean differences.

Based on the included 23 observational and 27 interventional studies, the association between levels of organic food intake and (i) pesticide exposure biomarker was assessed as “beneficial correlation,” (ii) toxic metals and carotenoids in the plasma was assessed as “no association,” (iii) fatty acids in human milk was assessed as “insufficient,” (iv) phenolics was assessed as “beneficial”, and serum parameters and antioxidant status was assessed as “inconsistent”. For diseases and functional changes, there was an overall “beneficial” association with organic food intake, and there were similar findings for obesity and body mass index. However, evidence for association of organic food intake with other single diseases was assessed as “insufficient” due to the limited number and extent of studies.

Organic food intake was found to have a beneficial impact in terms of reducing pesticide exposure, and the general effect on disease and functional changes (body mass index, male sperm quality) was appreciable. More long-term studies are required, especially for single diseases.

PROSPERO registration no. CRD42022350175.

• biological markers
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Health benefits of organic food, farming outlined in new report

February 8, 2017 – A report prepared for the European Parliament, co-authored by Harvard Chan School’s Philippe Grandjean , adjunct professor of environmental health, outlines the health benefits of eating organic food and practicing organic agriculture.

Why did the European Parliament commission this report and what was its most important takeaway?

The European Parliament is concerned about food safety and human health. They asked a group of experts from several countries to review the possible health advantages of organic food and organic farming. Our report reviews existing scientific evidence regarding the impact of organic food on human health, including in vitro and animal studies, epidemiological studies, and food crop analyses.

The most important information in this report is about pesticides in food. In conventional food, there are pesticide residues that remain in the food even after it’s washed. Organic foods are produced virtually without pesticides.

Authorities in both the European Union and the United States insist that current limits on the amount of pesticides in conventional produce are adequate to ensure that it’s perfectly safe. But those limits are based on animal studies, looking at the effect of one pesticide at a time. The human brain is so much more complex than the rat brain, and our brain development is much more vulnerable because there are so many processes that have to happen at the right time and in the right sequence—you can’t go back and do them over.

Three long-term birth cohort studies in the U.S. suggest that pesticides are harming children’s brains. In these studies, researchers found that women’s exposure to pesticides during pregnancy, measured through urine samples, was associated with negative impacts on their children’s IQ and neurobehavioral development, as well as with ADHD [attention deficit hyperactivity disorder] diagnoses. Also, one of the studies looked at structural brain growth using magnetic resonance imaging and found that the gray matter was thinner in children the higher their mothers’ exposure to organophosphates, which are used widely in pesticides. I think that’s quite scary.

Although the scientific evidence on pesticides’ impact on the developing brain is incomplete, pregnant and breastfeeding women, and women planning to become pregnant, may wish to eat organic foods as a precautionary measure because of the significant and possibly irreversible consequences for children’s health. If there are times when organic food isn’t available, one option is to buy foods that have to be peeled—baking potatoes or pineapples, for example—but stay away from produce like leafy vegetables. A good resource for learning about the pesticide content of various foods is the  Environmental Working Group , which maintains lists of produce with the highest pesticide levels as well as those with the lowest levels. There’s also a U.S. Environmental Protection Agency website that lists ways to reduce exposure to pesticides in food.

What were other key messages in the report?

We know that the overly prevalent use of antibiotics in farm animals is a contributing factor in the development of antibiotic resistance in bacteria—a major public health threat because this resistance can spread from animals to humans. On organic farms, the preventive use of antibiotics is restricted and animals are given more space to roam in natural conditions, which lowers their risk for infections. These techniques have been found to improve animal health, prevent disease, and minimize antibiotic resistance.

There are also other, though minor, advantages of organic food, such as higher contents of some nutrients, and less cadmium, but they are not of sufficient importance to guide food choices.

How might the European Parliament boost support for organic foods and organic farming? If it does, might that prompt similar changes in the U.S.?

Our report listed several policy options the European Parliament could consider to support and extend organic food production. For instance, politicians could decrease or waive taxes on organic food. They could decrease taxation on organic farmers. We also suggest that they support more research to learn more about the benefits of organic food.

If the European Parliament does take action, I hope it could influence practices also in the U.S. There is a lot of exchange of foods between the European Union and the U.S. Clearly, if the EU is going to favor organic products more in the future, that will open up an opportunity for U.S. producers of organic foods. And vice versa: If more products become available from EU farmers that are organic, that could be attractive to U.S. consumers. And perhaps the joint effect of that could be that organic farming, both in Europe and in the U.S., would become more sustainable economically as well as environmentally.

— Karen Feldscher

Organic food: panacea for health? ( The Lancet )

Read a slightly abbreviated version of the organic food report to the EU Parliament published October 27, 2017 in the journal Biomed Central : “Human health implications of organic food and organic agriculture: a comprehensive review”

*Editor’s note: This story was updated on February 12, 2017.

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Produce Wash Guide

Organic farmers are required to grow their crops without the use of synthetic agrochemicals, protecting you from the health risks associated with chemical pesticide residues found on conventional fruits and vegetables. However, when organic options are unavailable, you can still reduce pesticide exposure by using household remedies to wash your fruits and vegetables.

Check our guide for the most effective treatments in removing pesticides from various fruits and vegetables. All the information is derived from peer-reviewed research, with links provided for further reference. 

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Eating And Health

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• For Foodies

Is Organic More Nutritious? New Study Adds To The Evidence

Allison Aubrey

An assortment of organic vegetables are seen on display. A growing body of evidence documents how farming methods can influence the nutritional content of foods. Justin Sullivan/Getty Images hide caption

An assortment of organic vegetables are seen on display. A growing body of evidence documents how farming methods can influence the nutritional content of foods.

It's often a split-second decision.

You're in the produce aisle, and those organic apples on display look nice. You like the idea of organic — but they're a few bucks extra. Ditto for the organic milk and meat. Do you splurge? Or do you ask yourself: What am I really getting from organic?

Scientists have been trying to answer this question. And the results of a huge new meta-analysis published this week in the British Journal of Nutrition adds to the evidence that organic production can boost key nutrients in foods.

The study finds that organic dairy and meat contain about 50 percent more omega-3 fatty acids. The increase is the result of animals foraging on grasses rich in omega-3s, which then end up in dairy and meats. The findings are based on data pooled from more than 200 studies, and research in the U.S. has pointed to similar benefits.

"Omega-3s are linked to reductions in cardiovascular disease, improved neurological development and function, and better immune function," writes study co-author Chris Seal , a professor of food and human nutrition at Newcastle University in the U.K. "So we think it's important for nutrition," Seal told us. That said, organic meat and dairy contain far lower concentrations of omega-3s than what are found in fish such as salmon.

The findings are part of a growing body of evidence documenting how farming methods can influence the nutritional content of foods.

Another large meta-analysis published in 2014, also in the British Journal of Nutrition, found that organic crops — ranging from carrots and broccoli to apples and blueberries — have substantially higher concentrations of a range of antioxidants and other potentially beneficial compounds. That review included data from more than 300 studies.

For instance, organic crops had about 50 percent more anthocyanins and flavonols compared with conventional crops. Anthocyanins are compounds that give fruits and vegetables, such as blueberries, their blue, purple and red hues.

Consumption of these compounds is linked to a variety of benefits , including anti-inflammatory effects. Flavonol compounds — found widely in fruits and vegetables — have also been shown to protect cells from damage, which can help fend off disease.

Organic milk is processed at a dairy farm in Westbrook, Maine. A new meta-analysis finds that organic milk contains significantly more omega-3 fatty acids than its conventional counterpart. Pat Wellenbach/AP hide caption

Organic milk is processed at a dairy farm in Westbrook, Maine. A new meta-analysis finds that organic milk contains significantly more omega-3 fatty acids than its conventional counterpart.

So, what explains these boosts in antioxidant and other beneficial compounds in organic crops? Well, as Seal explains, it comes down to stress.

Organic crops tend to be exposed to higher levels of stress — including insect attacks, Seal says. And in response, they form compounds to help combat the stress.

For example, if a carrot fly lands on a carrot and starts to chew on it, what options does the plant have?

If it's a conventionally grown carrot, a pesticide can be applied to repel the pest.

But in organic agriculture, that carrot has to fend for itself a bit more. So, Seal explains, the carrot produces compounds known as polyacetylenes, which taste bitter to the carrot fly.

These polyacetylene compounds may help drive the fly away — and, serendipitously, this compound may benefit us as well.

Research in animals suggests polyacetylene compounds may play a role in reducing inflammation and cancer risk, but it's unclear how much must be eaten to benefit human health.

Current research aims to address this question, but the answer is difficult to suss out, given that our diets are so complex and our bodies may not absorb all the nutrients we eat. In fact, broadly speaking, this is the challenge in trying to isolate the benefits of micronutrients in our diet.

Another difference between organic and conventional crops is the way plants get nitrogen. Conventional crops are given steady doses of nitrogen from synthetic fertilizer. In organic systems, which rely heavily on crop rotation and composting, there's typically less nitrogen available.

As a result, organic crops tend to grow more slowly, and produce more of what scientists call secondary plant metabolites. These compounds also may be health-promoting when we eat them.

A study of tomatoes conducted at the University of California, Davis back in 2008 found that organic tomatoes have almost double the concentration of a beneficial flavonoid known as quercetin, compared with conventional tomatoes grown on an adjacent field.

The 2014 meta-analysis in the British Journal of Nutrition pointed to other differences in organic crops as well, including lower levels of pesticide residues on produce and lower concentrations of the metal cadmium, which is naturally occurring in soil.

And these findings — according to Carlo Leifert , a professor of agriculture at Newcastle and co-author of the latest study — suggest there are indeed benefits to buying and eating organic. "Taken together, the studies on crops, meat and milk suggest that a switch to organic fruit, vegetables, meat and dairy products would provide significantly higher amounts of dietary antioxidants and omega-3 fatty acids," Leifert wrote in a release about the new papers.

But plenty of skeptics remain. "Such small changes are unlikely to represent any nutritional or health benefit," writes Ian Givens , a professor of nutrition at the University of Reading. In a statement on the new findings, Givens points out that switching from conventional milk to organic milk would increase omega-3 intake by only very small margins.

And an analysis by researchers at Stanford University published several years ago concluded there was no good evidence that organic fruits and vegetables were more nutritious overall.

There are echoes of this finding in the newer meta-analysis studies. Although organic crops had higher levels of antioxidants, they did not consistently contain higher levels of vitamins. For instance, as we've reported , vitamin E levels didn't vary much between organic and conventional crops. And protein levels were lower in organic crops such as wheat.

Given the big picture, lots of experts say that, from a health perspective, what you eat matters more than whether you choose organic or conventional.

And at a time when most Americans don't eat the recommended servings of fruits and vegetables, perhaps the more important step is to add them to your diet — no matter what farming methods were used to grow them.

But if you like the environmental benefits of organic agriculture, these studies point to potential nutritional benefits as well, at least when it comes to maximizing the antioxidants and micronutrients you get from foods.

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Is Organic Food Healthier Than Conventional? Here's What a Dietitian Has to Say

We dive into the science to answer what organic means, if organic is better for your health than conventional and the research behind any health benefits of organic foods.

Lauren is an award-winning registered dietitian, author of three books and all-around lover of good food. After graduating with a bachelor's degree in food science and human nutrition and a master's degree in clinical nutrition, Lauren has worked in various nutrition-related settings, most currently writing nutrition-related content for online outlets including Verywell Health, PopSugar, The Kitchn, and EatingWell. Additionally, she manages the Instagram page @LaurenLovesNutrition, where people can receive evidence-based nutrition tips and updates.

Figuring out whether organic food should dominate your kitchen or if you can safely stick to conventionally grown items can be easier said than done. On the one hand, choosing organic food intuitively sounds like it is better for your health. But on the other hand, these options can be more costly when compared with conventional foods . And in some areas of the world, having access to organic choices can be challenging. Is it really worth the effort?

Let's set the record straight and dig into whether organic food is really healthier than conventional .

What is organic food?

While many of us have seen the words organic and conventional when grocery shopping, not all of us really know what the difference is. Sure, the word organic sounds healthy, but what does organic really mean?

The reality is that the words organic and conventional don't actually refer to how healthy a food is, but rather are an indication of how farmers grow and process the food.

The United States Department of Agriculture allows a food item to be considered organic if it is grown and processed according to federal guidelines addressing:

• soil quality
• animal raising practices
• pest and weed control
• use of additives

Organic producers rely on natural substances to be used as pesticides that are on an approved list provided by the USDA . Plus, these farmers use physical, mechanical or biologically based farming methods — which refers to how they plant, harvest and tend to their crops — and don't use most synthetic fertilizers and pesticides.

So, contrary to popular belief, organically grown produce is not pesticide-free. Rather, pesticides found on organic foods are not synthetic.

As for organic meat, regulations require that animals are raised in living conditions accommodating their natural behaviors (like grazing versus spending the day in a barn), and they are fed 100% organic feed and forage. Additionally, organic foods cannot contain any genetically modified organisms .

Ultimately, the difference between organic versus non-organic food or conventional food is that conventional does allow for the use of synthetic materials and genetically modified crops.

Is organic better for you?

The notion that organic food may be healthier than conventional is a trend that doesn't seem to be going anywhere. But if you are expecting your organic fruit or veggie to contain far more nutrients than your conventional option, you may be disappointed to learn the truth.

The fact is that there is little variation between organic and conventional food products in terms of macro nutritional value (read: protein, fat, carbohydrate and dietary fiber). And while other nutritional differences have been seen when comparing the two types of foods—namely higher antioxidant concentrations in some organic produce , increased levels of omega-3 fatty acids in organic dairy products and improved fatty acid profiles in organic meat products —the actual differences in the levels may be marginal when looking at the overall impact it has on a person's health .

If you are more focused on reducing your exposure to heavy metals (specifically cadmium ) and synthetic fertilizers and pesticide residues , then organic may be your best bet, as organic produce appears to have slightly lower levels of these components. But since clinical trials are sparse, the impact of this on human health is not clear .

It is true that observational trials suggest that there is a link between better health outcomes and choosing organic over conventional options . But, it is also known that consumers of organic food tend to eat more vegetables, fruit, whole grains and are more physically active—all factors that are associated with positive health outcomes . In other words, researchers question whether the better outcomes they observe when people eat more organic food are due to the way the food was produced or if it is because of the person's overall lifestyle choices.

Should you only choose organic food?

When people are deciding whether they should choose organic or conventionally grown food, ultimately, it is a matter of personal preference. While there does not appear to be any downside to choosing organic foods when it comes to supporting health, the cost and accessibility factors can certainly be a barrier to some.

Only 1 in 10 Americans are meeting the recommended amounts of fruit and vegetable consumption. And not eating adequate produce is linked to some unsavory outcomes, like an increased risk of developing certain cancers .

Therefore, the potential negative effects of choosing conventional foods on health should not be used as an argument for reducing fruit and vegetable consumption .

Instead, people should eat a wide variety of foods and wash their produce well before enjoying it, regardless of how it was produced. Limiting foods based on fear can result in some unwanted outcomes that nobody wants to have on their plate.

Bottom Line

The main difference between conventional and organic foods is the way that the food is produced. While some studies have found higher nutrient values in certain organic foods compared to their conventional counterparts, more research is needed to determine their impacts on long-term health. Plus, organic food is often sold at a higher price point than conventional, so it might not be realistic for some budgets. In summary, there might be some slight benefits to choosing organic foods in some circumstances, but you don't need to avoid foods if they are conventional, as both types of food are safe and nutritious.

Related Articles

• Open access
• Published: 27 October 2017

Human health implications of organic food and organic agriculture: a comprehensive review

• Axel Mie   ORCID: orcid.org/0000-0001-8053-3541 1 , 2 ,
• Helle Raun Andersen 3 ,
• Stefan Gunnarsson 4 ,
• Johannes Kahl 5 ,
• Emmanuelle Kesse-Guyot 6 ,
• Ewa Rembiałkowska 7 ,
• Gianluca Quaglio 8 &
• Philippe Grandjean 3 , 9  

Environmental Health volume  16 , Article number:  111 ( 2017 ) Cite this article

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This review summarises existing evidence on the impact of organic food on human health. It compares organic vs. conventional food production with respect to parameters important to human health and discusses the potential impact of organic management practices with an emphasis on EU conditions. Organic food consumption may reduce the risk of allergic disease and of overweight and obesity, but the evidence is not conclusive due to likely residual confounding, as consumers of organic food tend to have healthier lifestyles overall. However, animal experiments suggest that identically composed feed from organic or conventional production impacts in different ways on growth and development. In organic agriculture, the use of pesticides is restricted, while residues in conventional fruits and vegetables constitute the main source of human pesticide exposures. Epidemiological studies have reported adverse effects of certain pesticides on children’s cognitive development at current levels of exposure, but these data have so far not been applied in formal risk assessments of individual pesticides. Differences in the composition between organic and conventional crops are limited, such as a modestly higher content of phenolic compounds in organic fruit and vegetables, and likely also a lower content of cadmium in organic cereal crops. Organic dairy products, and perhaps also meats, have a higher content of omega-3 fatty acids compared to conventional products. However, these differences are likely of marginal nutritional significance. Of greater concern is the prevalent use of antibiotics in conventional animal production as a key driver of antibiotic resistance in society; antibiotic use is less intensive in organic production. Overall, this review emphasises several documented and likely human health benefits associated with organic food production, and application of such production methods is likely to be beneficial within conventional agriculture, e.g., in integrated pest management.

Peer Review reports

The long-term goal of developing sustainable food systems is considered a high priority by several intergovernmental organisations [ 1 , 2 , 3 ]. Different agricultural management systems may have an impact on the sustainability of food systems, as they may affect human health as well as animal wellbeing, food security and environmental sustainability. In this paper, we review the available evidence on links between farming system (conventional vs organic) and human health.

Food production methods are not always easy to classify. This complexity stems from not only the number and varying forms of conventional and organic agricultural systems but also resulting from the overlap of these systems. In this paper, we use the term “conventional agriculture” as the predominant type of intensive agriculture in the European Union (EU), typically with high inputs of synthetic pesticides and mineral fertilisers, and a high proportion of conventionally-produced concentrate feed in animal production. Conversely, “organic agriculture” is in accordance with EU regulations or similar standards for organic production, comprising the use of organic fertilisers such as farmyard and green manure, a predominant reliance on ecosystem services and non-chemical measures for pest prevention and control and livestock access to open air and roughage feed.

In 2015, over 50.9 million hectares, in 179 countries around the world, were cultivated organically, including areas in conversion [ 4 ]. The area under organic management (fully converted and in-conversion) has increased during the last decades in the European Union, where binding standards for organic production have been developed [ 5 , 6 ]. In the 28 countries forming the EU today, the fraction of organically cultivated land of total agricultural area has been steadily increasing over the last three decades. 0.1%, 0.6%, 3.6%, and 6.2% of agricultural land were organic in 1985, 1995, 2005, and 2015, respectively, equalling 11.2 million ha in 2015 [ 7 , 8 , 9 ]. In 7 EU Member States, at least 10% of the agricultural land is organic [ 7 ]. In 2003, 125,000 farms in the EU were active in organic agriculture, a number that increased to 185,000 in 2013 [ 10 ]. Between 2006 and 2015, the organic retail market has grown by 107% in the EU, to €27.1 billion [ 7 ].

This review details the science on the effects of organic food and organic food production on human health and includes

studies that directly address such effects in epidemiological studies and clinical trials.

animal and in vitro studies that evaluate biological effects of organic compared to conventional feed and food.

Focusing on narrower aspects of production, we then discuss the impact of the production system on

plant protection, pesticide exposure, and effects of pesticides on human health,

plant nutrition, the composition of crops and the relevance for human health,

animal feeding regimens, effects on the composition of animal foods and the relevance for human health.

animal health and well-being, the use of antibiotics in animal production, its role in the development of antibiotic resistance, and consequences of antibiotic resistance for public health.

In the discussion, we widen the perspective from production system to food system and sustainable diets and address the interplay of agricultural production system and individual food choices. The consequences of these aspects on public health are briefly discussed.

Due to a limited evidence base, minimal importance, lack of a plausible link between production system and health, or due to lack of relevance in the European Union, we do not or only briefly touch upon

singular food safety events such as outbreaks of diseases that are not clearly caused by the production system (hygiene regulations for plant production and for animal slaughtering and processing are for the most part identical for organic and conventional agriculture) or fraudulent introduction of contaminated feed into the feed market

historic events and historic sources of exposure, such as the BSE crisis caused by the now-banned practice of feeding cattle with meat and bone meal from cattle, or continuing effects of the historic use of DDT, now banned in all agricultural contexts globally

contaminants from food packaging

aspects of food processing, such as food additives

the presence of mycotoxins in consequence of post-harvest storage and processing which is governed chiefly by moisture and temperature in storage

the use of growth hormones in animal production, which is not permitted in the EU but in several other countries

Furthermore, aspects of environmental sustainability, such as biodiversity and greenhouse gas emissions, may also be affected by the agricultural production system [ 11 , 12 ] and may affect human health via food security [ 13 , 14 ]. While these indirect links are outside the scope of this review, we briefly touch on them in the discussion. Also, the focus of this article is on public health, not on occupational health of agricultural workers or local residents, although these issues are considered as part of the epidemiological evidence on pesticide effects. While agricultural standards vary between countries and regions, we maintain a global perspective when appropriate and otherwise focus on the European perspective.

The literature search for this review was carried out at first using the PubMed and Web of Science databases, while applying “organic food” or “organic agriculture” along with the most relevant keywords, through to the end of 2016 (more recent references were included, when relevant, although they were not identified through the systematic search). We made use of existing systematic reviews and meta-analyses when possible. In some cases, where scientific literature is scarce, we included grey literature e.g. from authorities and intergovernmental organisations. We also considered references cited in the sources located.

Association between organic food consumption and health: Findings from human studies

A growing literature is aiming at characterizing individual lifestyles, motivations and dietary patterns in regard to organic food consumption, which is generally defined from responses obtained from food frequency questionnaires [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Still, current research on the role of organic food consumption in human health is scarce, as compared to other nutritional epidemiology topics. In particular, long-term interventional studies aiming to identify potential links between organic food consumption and health are lacking, mainly due to high costs. Prospective cohort studies constitute a feasible way of examining such relationships, although compliance assessment is challenging. Considering a lack of biomarkers of exposure, the evaluation of the exposure, i.e. organic food consumption, will necessarily be based on self-reported data that may be prone to measurement error.

Some recent reviews have compiled the findings [ 24 , 25 , 26 ] from clinical studies addressing the association between consumption of organic food and health. These studies are scant and generally based on very small populations and short durations, thus limiting statistical power and the possibility to identify long-term effects. Smith-Spangler et al. [ 25 ] summarised the evidence from clinical studies that overall no clinically significant differences in biomarkers related to health or to nutritional status between participants consuming organic food compared to controls consuming conventional food. Among studies of nutrient intakes, the OrgTrace cross-over intervention study of 33 males, the plant-based fraction of the diets was produced in controlled field trials, but 12 days of intervention did not reveal any effect of the production system on the overall intake or bioavailability of zinc and copper, or plasma status of carotenoids [ 27 , 28 ].

In observational studies, a specific challenge is the fact that consumers who regularly buy organic food tend to choose more vegetables, fruit, wholegrain products and less meat, and tend to have overall healthier dietary patterns [ 18 , 29 ]. Each of these dietary characteristics is associated with a decreased risk for mortality from or incidence of certain chronic diseases [ 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Consumers who regularly buy organic food are also more physically active and less likely to smoke [ 18 , 19 , 37 ]. Depending on the outcome of interest, associations between organic vs conventional food consumption and health outcome therefore need to be carefully adjusted for differences in dietary quality and lifestyle factors, and the likely presence of residual confounding needs to be considered. In children, several studies have reported a lower prevalence of allergy and/or atopic disease in families with a lifestyle comprising the preference of organic food [ 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. However, organic food consumption is part of a broader lifestyle in most of these studies and associated with other lifestyle factors. Thus, in the Koala birth cohort of 2700 mothers and babies from the Netherlands [ 39 ], exclusive consumption of organic dairy products during pregnancy and during infancy was associated with a 36% reduction in the risk of eczema at age 2 years. In this cohort, the preference of organic food was associated with a higher content of ruminant fatty acids in breast milk [ 40 ], which in turn was associated with a lower odds ratio for parent-reported eczema until age 2y [ 45 ].

In the MOBA birth cohort study of 28,000 mothers and their offspring, women reporting a frequent consumption of organic vegetables during pregnancy exhibited a reduction in risk of pre-eclampsia [ 29 ] (OR = 0.79, 95% CI 0.62 to 0.99). No significant association was observed for overall organic food consumption, or five other food groups, and pre-eclampsia.

The first prospective study investigating weight change over time according to the level of organic food consumption included 62,000 participants of the NutriNet-Santé study. BMI increase over time was lower among high consumers of organic food compared to low consumers (mean difference as % of baseline BMI = − 0.16, 95% Confidence Interval (CI): −0.32; −0.01). A 31% (95% CI: 18%; 42%) reduction in risk of obesity was observed among high consumers of organic food compared to low consumers. Two separate strategies were chosen to properly adjust for confounders [ 46 ]. This paper thus confirms earlier cross-sectional analyses from the same study [ 18 ].

In regard to chronic diseases, the number of studies is limited. In the Nutrinet-Santé study, organic food consumers (occasional and regular), as compared to non-consumers, exhibited a lower incidence of hypertension, type 2 diabetes, hypercholesterolemia (in both males and females), and cardiovascular disease (in men) [ 47 ] but more frequently declared a history of cancer. Inherent to cross-sectional studies, reverse causation cannot be excluded; for example, a cancer diagnosis by itself may lead to positive dietary changes [ 48 ].

Only one prospective cohort study conducted in adults addressed the effect of organic food consumption on cancer incidence. Among 623,080 middle-aged UK women, the association between organic food consumption and the risk of cancer was estimated during a follow-up period of 9.3 y. Participants reported their organic food consumption through a frequency question as never, sometimes, or usually/always. The overall risk of cancer was not associated with organic food consumption, but a significant reduction in risk of non-Hodgkin lymphoma was observed in participants who usually/always consume organic food compared to people who never consume organic food (RR = 0.79, 95% CI: 0.65; 0.96) [ 37 ].

In conclusion, the link between organic food consumption and health remains insufficiently documented in epidemiological studies. Thus, well-designed studies characterized by prospective design, long-term duration and sufficient sample size permitting high statistical power are needed. These must include detailed and accurate data especially for exposure assessment concerning dietary consumption and sources (i.e. conventional or organic).

Experimental in vitro and animal studies

In vitro studies.

The focus on single plant components in the comparison of crops from organic and conventional production, as discussed further below, disregards the fact that compounds in food do not exist and act separately, but in their natural context [ 49 ]. In vitro studies of effects of entire foods in biological systems such as cell lines can therefore potentially point at effects that cannot be predicted from chemical analyses of foods, although a limitation is that most cells in humans are not in direct contact with food or food extracts.

Two studies have investigated the effect of organic and conventional crop cultivation on cancer cell lines, both using crops produced under well-documented agricultural practices and with several agricultural and biological replicates. In the first study extracts from organically grown strawberries exhibited stronger antiproliferative activity against one colon and one breast cancer cell line, compared to the conventionally produced strawberries [ 50 ]. In the second study [ 51 ] the extracts of organic naturally fermented beetroot juices induced lower levels of early apoptosis and higher levels of late apoptosis and necrosis in a gastric cancer cell line, compared to the conventional extracts. Both studies thus demonstrated notable differences in the biological activity of organic vs. conventionally produced crop extracts in vitro, which should inspire further research. However, neither of these studies allows for the distinction of a selective antiproliferative effect on cancer cells, and general cell toxicity. Therefore it cannot be determined which of the organic or conventional food extracts, if any, had the preferable biological activity in terms of human health.

Animal studies of health effects

Considering the difficulties of performing long-term dietary intervention studies in humans, animal studies offer some potential of studying long-term health effects of foods in vivo. However, extrapolation of the results from animal studies to humans is not straight-forward. Studies in this field started almost 100 years ago. A review of a large number of studies [ 52 ] concluded that positive effects of organic feed on animal health are possible, but further research is necessary to confirm these findings. Here we focus on the main health aspects.

In one of the best-designed animal studies, the second generation chickens receiving the conventionally grown feed demonstrated a faster growth rate. However, after an immune challenge, chickens receiving organic feed recovered more quickly [ 53 ]. This resistance to the challenge has been interpreted as a sign of better health [ 54 , 55 ].

In one carefully conducted crop production experiment, followed by a rat feeding trial, the production system had an apparent effect on plasma-IgG concentrations but not on other markers of nutritional or immune status [ 56 ]. A two-generational rat study based on feed grown in a factorial design (fertilisation x plant protection) of organic and conventional practices revealed that the production system had an effect on several physiological, endocrine and immune parameters in the offspring [ 57 ]. Most of the effects identified were related to the fertilisation regimen. None of these studies found that any of the feed production systems was more supportive of animal health.

Several other studies, mostly in rats, have reported some effect of the feed production system on immune system parameters [ 57 , 58 , 59 , 60 ]. However, the direct relevance of these findings for human health is uncertain.

Collectively, in vitro and animal studies have demonstrated that the crop production system does have an impact on certain aspects of cell life, the immune system, and overall growth and development. However, the direct relevance of these findings for human health is unclear. On the other hand, these studies may provide plausibility to potential effects of conventional and organic foods on human health. Still, most of the outcomes observed in animal studies have not been examined in humans so far.

Plant protection in organic and conventional agriculture

Plant protection in conventional agriculture is largely dependent on the use of synthetic pesticides. Conversely, organic farming generally relies on prevention and biological means for plant protection, such as crop rotation, intercropping, resistant varieties, biological control employing natural enemies, hygiene practices and other measures [ 61 , 62 , 63 , 64 ]. Yet, certain pesticides are approved for use in organic agriculture. In the EU, pesticides (in this context, more specifically chemical plant-protection products; micro- and macrobiological agents are excluded from this discussion due to their low relevance for human health) are approved after an extensive evaluation, including a range of toxicological tests in animal studies [ 65 ]. Acceptable residue concentrations in food are calculated from the same documentation and from the expected concentrations in accordance with approved uses of the pesticides. Currently, 385 substances are authorised as pesticides in the EU (Table  1 ). Of these , 26 are also approved for use in organic agriculture [ 6 , 66 ] as evaluated in accordance with the same legal framework.

Most of the pesticides approved for organic agriculture are of comparatively low toxicological concern for consumers because they are not associated with any identified toxicity (e.g. spearmint oil, quartz sand), because they are part of a normal diet or constitute human nutrients (e.g. iron, potassium bicarbonate, rapeseed oil) or because they are approved for use in insect traps only and therefore have a negligible risk of entering the food chain (i.e. the synthetic pyrethroids lambda-cyhalothrin and deltamethrin, and pheromones). Two notable exceptions are the pyrethrins and copper. Pyrethrins, a plant extract from Chrysanthemum cinerariaefolium, share the same mechanism of action as the synthetic pyrethroid insecticides, but are less stable. Copper is an essential nutrient for plants, animals and humans, although toxic at high intakes and of ecotoxicological concern due to toxicity to aquatic organisms.

Plant protection practices developed in and for organic agriculture may be of benefit to the entire agricultural system [ 67 , 68 , 69 , 70 ]. This is of specific value for the transition towards sustainable use of pesticides in the EU, which has a strong emphasis on non-chemical plant protection measures including prevention and biological agents [ 63 , 64 ]. Further, steam treatment of cereal seeds for the prevention of fungal diseases ( http://thermoseed.se/ ) has been developed driven by the needs of organic agriculture as an alternative to chemical seed treatments [ 71 , 72 ]. These methods are now also being marketed for conventional agriculture, specifically for integrated pest management (IPM) [ 73 ].

Pesticide use – Exposure of consumers and producers

One main advantage of organic food production is the restricted use of synthetic pesticides [ 5 , 6 ], which leads to low residue levels in foods and thus lower pesticide exposure for consumers. It also reduces the occupational exposure of farm workers to pesticides and drift exposures of rural populations. On average over the last three available years, EFSA reports pesticide residues below Maximum Residue Levels (MRL) in 43.7% of all and 13.8% of organic food samples. MRLs reflect the approved use of a pesticide rather than the toxicological relevance of the residue. There are no separate MRLs for organic products. A total of 2.8% of all and 0.9% of organic samples exceeded the MRL, which may be due to high residue levels or due to low levels but unapproved use of a particular pesticide on a particular crop [ 74 , 75 , 76 ]. Of higher toxicological relevance are risk assessments, i.e. expected exposure in relation to toxicological reference values. On average 1.5% of the samples were calculated to exceed the acute reference dose (ARfD) for any of the considered dietary scenarios, with the organophosphate chlorpyrifos accounting for approximately half of these cases and azole fungicides (imazalil, prochloraz, and thiabendazole) for approximately 15%. None (0%) of the organic samples exceeded the ARfD [ 74 ]. Residues of more than one pesticide were found in approximately 25% of the samples but calculations of cumulative risks were not included in the reports [ 74 , 75 , 76 ].

The only cumulative chronic risk assessment comparing organic and conventional products known to us has been performed in Sweden. Using the hazard index (HI) method [ 77 ], adults consuming 500 g of fruit, vegetables and berries per day in average proportions had a calculated HI of 0.15, 0.021 and 0.0003, under the assumption of imported conventional, domestic conventional, and organic products, respectively [ 78 ]. This indicates an at least 70 times lower exposure weighted by toxicity for a diet based on organic foods. There are several routes by which pesticides not approved for use in organic agriculture may contaminate organic products, including spray drift or volatilisation from neighbouring fields, fraudulent use, contamination during transport and storage in vessels or storages where previously conventional products have been contained, and mislabelling by intention or mistake. Overall, however, current systems for the certification and control of organic products ensure a low level of pesticide contamination as indicated by chronic and acute risks above, although they still can be improved [ 79 ].

The general population’s exposure to several pesticides can be measured by analysing blood and urine samples, as is routinely done in the US [ 80 ] although not yet in Europe. However, a few scattered European studies from France [ 81 , 82 , 83 ], Germany [ 84 ], the Netherlands [ 85 ], Spain [ 86 ], Belgium [ 87 ], Poland [ 88 ] and Denmark [ 89 ] have shown that EU citizens are commonly exposed to organophosphate and pyrethroid insecticides. A general observation has been higher urinary concentrations of pesticide metabolites in children compared to adults, most likely reflecting children’s higher food intake in relation to body weight and maybe also more exposure-prone behaviours. The urinary concentrations of generic metabolites of organophosphates (dialkyl phosphates, DAPs) and pyrethroids (3-phenoxybenzoic acid, 3-PBA) found in most of the European studies were similar to or higher than in the US studies. Although urinary metabolite concentration might overestimate the exposure to the parent compounds, due to ingestion of preformed metabolites in food items, several studies have reported associations between urinary metabolite concentrations and neurobehavioral deficits as described below. Besides, the metabolites are not always less toxic than the parent compounds [ 90 ].

For the general population, pesticide residues in food constitute the main source of exposure for the general population. This has been illustrated in intervention studies where the urinary excretion of pesticides was markedly reduced after 1 week of limiting consumption to organic food [ 91 , 92 , 93 ]. Similar conclusions emerged from studies investigating associations between urinary concentrations of pesticides and questionnaire information on food intake, frequency of different foodstuffs and organic food choices. Thus a high intake of fruit and vegetables is positively correlated with pesticide excretion [ 94 ], and frequent consumption of organic produce is associated with lower urinary pesticide concentration [ 95 ].

Pesticide exposure and health effects

The regulatory risk assessment of pesticides currently practised in the EU is comprehensive, as a large number of toxicological effects are addressed in animal and other experimental studies. Nonetheless, there are concerns that this risk assessment is inadequate at addressing mixed exposures, specifically for carcinogenic effects [ 96 ] as well as endocrine-disrupting effects [ 97 , 98 ] and neurotoxicity [ 99 ]. Furthermore, there are concerns that test protocols lag behind independent science [ 100 ], studies from independent science are not fully considered [ 101 ] and data gaps are accepted too readily [ 102 ]. These concerns primarily relate to effects of chronic exposure and to chronic effects of acute exposure, which are generally more difficult to discover than acute effects. Most studies rely on urinary excretion of pesticide metabolites and a common assumption is that the subjects were exposed to the parent chemicals, rather than the metabolites.

The overall health benefits of high fruit and vegetable consumption are well documented [ 31 , 35 ]. However, as recently indicated for effects on semen quality [ 103 ], these benefits might be compromised by the adverse effects of pesticide residues. When benefits are offset by a contaminant, a situation of inverse confounding occurs, which may be very difficult to adjust for [ 104 ]. The potential negative effects of dietary pesticide residues on consumer health should of course not be used as an argument for reducing fruit and vegetable consumption. Neither should nutrient contents be used to justify exposures to pesticides. Exposures related to the production of conventional crops (i.e. occupational or drift exposure from spraying) have been related to an increased risk of some diseases including Parkinson’s disease [ 105 , 106 , 107 ], type 2 diabetes [ 108 , 109 ] and certain types of cancers including non-Hodgkin lymphoma [ 110 ] and childhood leukaemia or lymphomas, e.g. after occupational exposure during pregnancy [ 105 , 111 ] or residential use of pesticides during pregnancy [ 105 , 112 ] or childhood [ 113 ]. To which extent these findings also relate to exposures from pesticide residues in food is unclear. However, foetal life and early childhood are especially vulnerable periods for exposure to neurotoxicants and endocrine disruptors. Even brief occupational exposure during the first weeks of pregnancy, before women know they are pregnant, have been related to adverse long-lasting effects on their children’s growth, brain functions and sexual development, in a Danish study on greenhouse worker’s children [ 114 , 115 , 116 , 117 , 118 ].

In order to assess the potential health risk for consumers associated with exposure to dietary pesticides, reliance on epidemiological studies of sensitive health outcomes and their links to exposure measures is needed. Such studies are complicated both by difficult exposure assessment and the necessary long-term follow-up. The main focus so far has been on cognitive deficits in children in relation to their mother’s exposure level to organophosphate insecticides during pregnancy. This line of research is highly appropriate given the known neurotoxicity of many pesticides in laboratory animal models [ 99 ] and the substantial vulnerability of the human brain during early development [ 119 ].

Most of the human studies have been carried out in the US and have focused on assessing brain functions in children in relation to prenatal organophosphate exposure. In a longitudinal birth cohort study among farmworkers in California (the CHAMACOS cohort), maternal urinary concentrations of organophosphate metabolites in pregnancy were associated with abnormal reflexes in neonates [ 120 ], adverse mental development at 2 years of age [ 121 ], attention problems at three and a half and 5 years [ 122 ], and poorer intellectual development at 7 years [ 123 ]. In accordance with this, a birth cohort study from New York reported impaired cognitive development at ages 12 and 24 months and 6 – 9 years related to maternal urine concentrations of organophosphates in pregnancy [ 124 ]. In another New York inner-city birth cohort, the concentration of the organophosphate chlorpyrifos in umbilical cord blood was associated with delayed psychomotor and mental development in children in the first 7 years of life [ 125 ], poorer working memory and full-scale IQ at 7 years of age [ 126 ], structural changes, including decreased cortical thickness, in the brain of the children at school age [ 127 ], and mild to moderate tremor in the arms at 11 years of age [ 128 ]. Based on these and similar studies, chlorpyrifos has recently been categorised as a human developmental neurotoxicant [ 129 ]. Recent reviews of neurodevelopmental effects of organophosphate insecticides in humans conclude that exposure during pregnancy – at levels commonly found in the general population – likely have negative effects on children’s neurodevelopment [ 130 , 131 , 132 ]. In agreement with this conclusion, organophosphate pesticides considered to cause endocrine disruption contribute the largest annual health cost within the EU due to human exposures to such compounds, and these costs are primarily due to neurodevelopmental toxicity, as discussed below.

Since growth and functional development of the human brain continues during childhood, the postnatal period is also assumed to be vulnerable to neurotoxic exposures [ 119 ]. Accordingly, five-year-old children from the CHAMACOS cohort had higher risk scores for development of attention deficit hyperactive disorder (ADHD) if their urine concentration of organophosphate metabolites was elevated [ 122 ]. Based on cross-sectional data from the NHANES data base, the risk of developing ADHD increases by 55% for a ten-fold increase in the urinary concentration of organophosphate metabolites in children aged 8 to 15 years [ 133 ]. Also based on the NHANES data, children with detectable concentrations of pyrethroids in their urine are twice as likely to have ADHD compared with those below the detection limit [ 134 ]. In addition, associations between urinary concentrations of pyrethroid metabolites in children and parent-reported learning disabilities, ADHD or other behavioural problems in the children have recently been reported in studies from the US and Canada [ 135 , 136 ].

So far only few prospective studies from the EU addressing associations between urinary levels of pesticides and neurodevelopment in children from the general population have been published. Three studies are based on the PELAGIE cohort in France and present results for organophosphates and pyrethroids respectively [ 81 , 82 , 137 ]. While no adverse effects on cognitive function in six-year-old children were related to maternal urine concentrations of organophosphates during pregnancy, the concentration of pyrethroid metabolites was associated with internalising difficulties in the children at 6 years of age. Also, the children’s own urinary concentrations of pyrethroid metabolites were related to decrements in verbal and memory functions and externalising difficulties and abnormal social behaviour. While this sole European study did not corroborate US birth cohort studies results showing that exposure during pregnancy to organophosphate insecticides at levels found in the general population may harm brain development in the foetus, the exposure levels measured in the PELAGIE cohort were considerably lower for both organophosphates and pyrethroids than those measured in other European studies as well as in studies from the US and Canada. For example, the median urine concentration of organophosphate metabolites in pregnant women in the PELAGIE cohort was 2 – 6 times lower than for pregnant women in other studies [ 85 , 122 , 138 ] and the concentration of the common pyrethroid metabolite 3-PBA was only detectable in urine samples from 30% of the women compared to 80–90% in other studies [ 88 , 139 ]. Thus, to supplement the French study and the previously mentioned Danish study of greenhouse worker’s children, additional studies that include more representative exposure levels for EU citizens are desirable.

Although exposure levels found in European countries are generally similar to or slightly higher than concentrations found in the US studies, the risk of adverse effects on neurodevelopment in European populations needs to be further characterised. The organophosphate insecticides contributing to the exposure might differ between the US and the EU, also in regard to oral and respiratory intakes. According to the European Food Safety Agency (EFSA), of all the organophosphate insecticides, chlorpyrifos most often exceeds the toxicological reference value (ARfD) [ 74 ]. A recent report utilised US data on adverse effects on children’s IQ levels at school age to calculate the approximate costs of organophosphate exposure in the EU. The total number of IQ points lost due to these pesticides was estimated to be 13 million per year, representing a value of about € 125 billion [ 140 ], i.e. about 1% of the EU’s gross domestic product. Although there is some uncertainty associated with this calculation, it most likely represents an underestimation, as it focused only on one group of pesticides.

Unfortunately, epidemiological evidence linking pesticide exposure and human health effects is rarely regarded as sufficiently reliable to take into account in the risk assessment conducted by regulatory agencies. For example, the conclusion from the epidemiological studies on chlorpyrifos is that an association of prenatal chlorpyrifos exposure and adverse neurodevelopmental outcomes is likely, but that other neurotoxic agents cannot be ruled out, and that animal studies show adverse effects only at 1000-fold higher exposures [ 141 ]. A recent decrease of the maximum residue limit for chlorpyrifos in several crops [ 142 , 143 ] was based on animal studies only [ 144 ], but the limits for the sister compound, chlorpyrifos-methyl were unchanged. This case highlights a major limitation to current approaches to protecting the general population against a broad variety of pesticides.

Production system and composition of plant foods

Fertilisation in organic agriculture is based on organic fertilisers such as farmyard manure, compost and green fertilisers, while some inorganic mineral fertilisers are used as supplements. Nitrogen (N) input is limited to 170 kg/ha * year [ 5 , 145 ]. In conventional agriculture, fertilisation is dominated by mineral fertiliser, although farmyard manure is also common in some countries. There is no general limit on N input. Typically, crop yield is limited by plant N availability in organic but not in conventional systems [ 146 ] Phosphorus (P) input is on average similar or slightly lower in organic systems [ 147 ].

In the absence of particular nutrient deficiency, focusing on single nutrients may be of limited value for evaluating the impact of a food or diet on human health [ 49 ]; studies of actual health effects, as discussed above, are generally more informative than studies of single nutrients.

Overall crop composition

Metabolomics [ 148 , 149 , 150 , 151 , 152 ], proteomics [ 153 , 154 ] and transcriptomics [ 155 , 156 ] studies in controlled field trials provide evidence that the production system has an overall influence on crop development, although there is no direct relevance of these studies for human health. Furthermore, the generally lower crop yield in organic systems [ 146 ] as such indicates an effect of management strategy on plant development.

Several systematic reviews and meta-analyses [ 25 , 157 , 158 , 159 ] with different scopes, inclusion criteria and statistical methods have summarised several hundred original studies reporting some aspect of plant chemical composition in relation to conventional and organic production, in search of overall trends across crops, varieties, soils, climates, production years etc. While the overall conclusions of these systematic reviews look contradictory at first sight, there is agreement between them in most of the detailed findings:

Nitrogen and phosphorus

Existing systematic reviews have consistently found lower total nitrogen (7% [ 157 ], 10% [ 159 ]) and higher phosphorus (standardised mean difference (SMD) 0.82 [ 25 ], 8% [ 157 ]) in organic compared to conventional crops. These findings lack direct relevance for human health. However, considering the differences in fertilisation strategies discussed above, and the fundamental importance of N, P [ 160 , 161 , 162 ], and the N:P ratio [ 163 ] for plant development, this may lend some plausibility to other observed effects of the production system on crop composition.

Systematic reviews generally agree that the concentration of macronutrients, vitamins, and minerals in crops is either not at all or only slightly affected by the production system. For example, ascorbic acid (vitamin C) has received most attention in this context. Meta-analyses report only small effect sizes of the organic production system on vitamin C content [ 25 , 158 , 159 ].

Polyphenols

(Poly)phenolic compounds are not essential nutrients for humans but may play a role in preventing several non-communicable diseases, including cardiovascular disease, neurodegeneration and cancer [ 164 ]. The detailed mechanisms are complex and not fully understood [ 164 ]. Several environmental and agronomic practices affect the phenolic composition of the crop, including light, temperature, availability of plant nutrients and water management [ 165 ]. Under conditions of high nitrogen availability, many plant tissues show a decreased content of phenolic compounds, although there are examples of an opposite relationship [ 165 ].

Meta-analyses report modest effect sizes of the production system on total phenolics content, e.g. an increase of 14 – 26% [ 25 , 158 , 159 ]. For some narrower groups of phenolic compounds, larger relative concentration differences (in percent) between organic and conventional crops have been reported [ 159 ]. However, such findings represent unweighted averages typically from small and few studies, and are therefore less reliable.

Collectively the published meta-analyses indicate a modestly higher content of phenolic compounds in organic food, but the evidence available does not constitute a sufficient basis for drawing conclusions on positive effects of organic compared to conventional plant products in regard to human health.

Cadmium and other toxic metals

Cadmium (Cd) is toxic to the kidneys, can demineralise bones and is carcinogenic [ 166 ]. Cd is present naturally in soils, and is also added to soils by P fertilisers and atmospheric deposition. Several factors, including soil structure and soil chemistry, humus content and pH, affect the plant availability of Cd [ 167 ]. The application of Cd-containing fertilisers increases Cd concentrations in the crops [ 167 , 168 ]. Low soil organic matter generally increases the availability of Cd for crops [ 169 ], and organically managed farms tend to have higher soil organic matter than conventionally managed farms [ 11 ].

The source of Cd in mineral fertilisers is the raw material phosphate rock. The European average Cd content in mineral fertilisers is reported as 68 mg Cd/kg P [ 170 ] or 83 mg Cd/kg P [ 171 ]. The content of Cd in farmyard manure is variable but apparently in many cases lower: Various types of animal manure in a German collection averaged between 14 and 37 mg Cd/kg P [ 172 ].

Smith-Spangler et al. [ 25 ] found no significant difference in the Cd content of organic and conventional crops (SMD = −0.14, 95% CI -0.74 – 0.46) in their meta-analysis, while Barański et al. [ 159 ] report significantly 48% higher Cd concentration in conventional compared to organic crops (SMD = -1.45, 95% CI -2.52 to −0.39) in another meta-analysis largely based on the same underlying original studies, albeit with different inclusion criteria. We contacted the authors of these meta-analyses in order to understand this discrepancy. An updated version of the Barański meta-analysis, in which some inconsistencies have been addressed and which has been provided by the original authors [ 173 ], shows a significant 30% (SMD = −0.56, 95% CI -1.08 to −0.04) elevations of Cd contents in conventional compared to organic crops; in subgroup analysis, this difference is restricted to cereal crops. No updated meta-analysis was available for Smith-Spangler’s analysis [ 25 ]; apparently, two large well-designed studies with tendencies towards a lower Cd content in organic crops were not considered [ 174 , 175 ] although they appear to fulfil the inclusion criteria. Also, a correction for multiple testing has been imposed, which may be overly conservative, given the prior knowledge that mineral fertilisers constitute an important source of Cd to soils and crops. It is unclear how these points would affect the results of Smith-Spangler’s meta-analysis.

There are short-term and long-term effects of Cd influx from fertilisers on the Cd content of crops [ 167 ] but no long-term study comparing Cd content in organic and conventional crops is available. In absence of such direct evidence, two long-term experiments indicate a higher slope in Cd concentration over time for minerally fertilised compared to organically fertilised cereal crops [ 176 , 177 ], after over 100 years of growing.

A lower Cd content of organic crops is therefore plausible due to a lower Cd content in the fertilisers used in organic farming, and potentially due to higher soil organic matter in organic farmland. The general population’s Cd exposure is close to, and in some cases above, the tolerable intake and therefore their exposure to Cd should be reduced. For non-smokers, food is the primary source of exposure, with cereals and vegetables being the most important contributors [ 168 ].

For other toxic metals including lead, mercury and arsenic, no differences in concentration in organic and conventional crops have been reported [ 25 , 159 ]. Uranium (U) is also present as a contaminant of concern in mineral P fertilisers [ 178 ], but less so in organic fertilisers [ 179 ], and consequently manure-based cropping systems have a lower U load than mineral-fertilised systems at equal P load [ 179 ]. Uranium appears to accumulate in mineral-fertilised soils [ 180 ], and agricultural activity may increase the U content of surface and groundwater [ 181 , 182 ]. However, no evidence was found comparing uranium contents of organic and conventional products.

Fungal toxins

Regarding fungal toxins in crops, one meta-analysis has reported a lower contamination of organic compared to conventional cereal crops with deoxynivalenol (DON), produced by certain fusarium species [ 25 ]. Although not fully understood, fungicide applications may alter fungal communities on cereal leaves, potentially weakening disease-suppressive species [ 183 , 184 ]. Also, crop rotations including non-cereal crops may contribute to lower infestation with fusarium [ 185 ], while N availability is positively associated with cereal DON content [ 186 ]. These factors give plausibility to the observed lower DON contamination in organic cereals. In the EU, the mean chronic exposure of toddlers, infants and children to DON is above the tolerable daily intake (TDI), with grains and grain-based products being the main contributors to total exposure. The TDI is based on decreased body weight gain observed in mice [ 187 ]. The production system does not have any observed effect on the concentration of ochratoxin A (OTA), another fungal toxin of importance in cereal production [ 25 ].

Animal-based foods

By regulation, herbivores in organic production receive at least 60% of their feed intake as roughage on a dry matter basis. Depending on the seasonal availability of pastures, roughage can be fresh, dried, or silage. Also omnivores in organic production receive roughage as part of their daily feed, and poultry has access to pasture [ 6 ]. Corresponding regulations are for the most part missing in conventional animal production. In consequence, feeding strategies in organic animal production include a higher fraction of roughage compared to conventional systems, e.g. for dairy cows [ 188 , 189 ].

Fatty acids

Much of the focus of existing research on compositional differences of organic and conventional animal-based foods is on the fatty acid composition, with a major interest in omega-3 FAs due to their importance for human health. Some studies also address the content of minerals and vitamins.

The FA composition of the feed is a strong determinant of the fatty acid composition of the milk, egg or meat [ 190 , 191 ]. Grass and red clover, typical roughage feeds, contain between 30% and 50% omega-3 FA of total FA, while the concentrate feeds cereals, soy, corn, and palm kernel cake all contain below 10% omega-3 FA of total FA [ 190 ]. Like humans, farm animals turn a small part of dietary alpha-linolenic acid into long-chain omega-3 fatty acids with the help of elongase and desaturase enzymes.

For cow’s milk, a recent meta-analysis reports conclusively an approximately 50% higher content of total omega-3 fatty acids (as percent of total fatty acids) in organic compared to conventional milk [ 192 ], generally confirming earlier reviews [ 25 , 189 ]. Also, the content of ruminant FAs (a group of natural trans FAs produced in the cow’s rumen) is higher in organic milk. The content of saturated fatty acids, mono-unsaturated fatty acids and omega-6 PUFA was similar in organic and conventional milk [ 192 ].

A considerable statistical heterogeneity in these findings is reported. Individual differences described above are based on results from between 11 and 19 included studies. The observed differences are plausible, because they are directly linked to differences in feeding regimens. It should also be noted that several other factors influence the fatty acid composition in milk [ 193 ]. Specifically, the season (indoor vs. outdoor) has an impact on the feeding regime [ 188 ] and therefore on the omega-3 content of milk. However, the content of omega-3 fatty acids is higher in organic milk during both the outdoor and indoor seasons [ 189 ].

For eggs, it is likewise well described that the FA composition of the feed [ 190 ] and consequently the access to pasture [ 194 , 195 ] such as in organic systems, is a strong determinant of the fatty acid composition of the egg. However, only few studies have compared the FA composition in organic and conventional eggs [ 196 ] and a systematic review is not available. A higher omega-3 content of organic eggs is plausible but has not been documented.

A total of 67 original studies report compositional aspects of meat (mainly beef, chicken, lamb, and pork) from organic and conventional husbandry and were recently summarised in a meta-analysis [ 197 ]. Based on 23 and 21 studies respectively, the content of total PUFA and omega-3 PUFA was found to be significantly higher (23 and 47%, respectively) in organic compared to conventional meats. Weighted by average consumption in Europe, choosing organic instead of conventional meat, while maintaining a constant consumption, increased the intake of PUFA and omega-3 FA from meat by 17 and 22%, respectively [ 198 ]. These findings are plausible, especially in the case of omega-3 PUFA, considering the known differences in feeding regimens in organic and conventional production. However, few studies were available for each analysis, leaving many analyses with high uncertainty and poor statistical power. Furthermore, fatty acid metabolism differs between ruminants and monogastric animals [ 190 ]. Also, the actual differences in feeding regimens between conventionally and organically raised animals may differ by species, and by country. The variation between studies and between species was large, and the overall reliability of these results is therefore lower compared to milk above. This meta-analysis therefore indicates a plausible increase in omega-3 contents in organic meats, but more well-designed studies are needed to confirm this effect [ 197 ].

Dairy products account for 4–5% of the total PUFA intake in most European populations, while meat and meat products contribute another 7–23% [ 199 ]. The contribution of milk fat to omega-3 PUFA intake (approximated as intake of α-linolenic acid) has been estimated at 5–16% [ 200 , 201 ], while meat contributes with 12–17% [ 201 , 202 ]. The effect of exchanging organic for conventional dairy products on omega-3 PUFA intake while maintaining a constant consumption has not been examined rigorously. From the intake and composition data presented here, it can be estimated that choosing organic products would increase the average dietary omega-3 PUFA intake by 2.5–8% (dairy) and by a less certain 2.5–4% (meat). A recent preliminary estimate based on FAO food supply data resulted in similar numbers [ 198 ]. For certain population groups and fatty acids, these numbers could be higher, and an increased omega-3 PUFA consumption is generally desirable, as some subpopulations have a lower-than-recommended intake of omega-3 PUFA [ 203 ]. However, overall, the effect of the animal production system on omega-3 PUFA intake is minor, and no specific health benefits can be derived. Furthermore, other dietary omega-3 PUFA sources, specifically certain plant oils and fish, are available that carry additional benefits [ 204 , 205 , 206 ]. The existence of specific health benefits of ruminant trans fatty acids (as opposed to industrial trans fatty acids) is indicated by some studies [ 207 ] but not strongly supported [ 208 ]. Taking into account the actually consumed amounts of ruminant trans fatty acids, this is likely lacking public health relevance [ 208 ].

Trace elements and vitamins

A recent meta-analysis points to a significantly higher content of iodine (74%) and selenium (21%) in conventional milk and of iron (20%) and tocopherol (13%) in organic milk based on six, four, eight and nine studies respectively [ 192 ]. Iodine deficiency during pregnancy and infancy leads to impairment of brain development in the offspring, while excess iodine intake is associated with similar effects, and the window of optimal iodine intake is relatively narrow [ 209 ]. Overall, iodine intake in Europe is low and mild deficiency is prevalent [ 210 ]. The preferred way of correcting deficiency is salt iodisation [ 210 , 211 ], because salt is consumed almost universally and with little seasonal variation [ 212 ].

Feed iodine supplementation is not linked by regulation to the production system in the EU, as iodine is listed as approved feed additive, and the maximum amount of supplementation is the same for all milk production. Optimum dairy cow supplementation should be seen in relation to other national strategies for human iodine intake. This should also take into account human subpopulations with low or no intake of dairy products.

For tocopherol, selenium and iron, a higher content is generally desirable, and in the case of selenium milk is an important source. However, the concentration differences between organic and conventional milk are modest and based on a few studies only.

Antibiotic resistant bacteria

Overly prevalent prophylactic use of antibiotics in animal production is an important factor contributing to increasing human health problems due to resistant bacteria. Antibiotic use is strongly restricted in organic husbandry, which instead aims to provide good animal welfare and enough space in order to promote good animal health.

Antibiotics constitute an integral part of intensive animal production today, and farm animals may act as important reservoirs of resistant genes in bacteria [ 213 , 214 ]. It is reported that a substantial proportion (50 – 80%) of antibiotics are used for livestock production worldwide [ 215 ]. On a “per kg biomass” basis, in 2014, the amount of antimicrobial drugs consumed by farm animals was slightly higher than the antimicrobial drugs used for humans in the 28 EU/EEA countries surveyed, with substantial differences between countries regarding volumes and types of substances [ 216 ].

In recent decades, there have been increasing concerns that the use of antibiotics in livestock would contribute to impairing the efficiency of antibiotic treatment in human medical care [ 217 ]. Despite the lack of detailed information on transmission routes for the vast flora of antibiotic-resistant bacteria and resistance genes, there is a global need for action to reduce the emerging challenges associated with the reduced efficiency of antibiotics and its consequences for public health, as well as for the environment more generally [ 218 , 219 ].

The use of antibiotics may increase the economic outcome of animal production [ 220 , 221 ], but the spreading of multi-resistant genes is not just a problem for the animal production sector alone. Negative effects are affecting parts of society not directly associated with livestock production. This means that the costs of side effects are borne by society in general and not primarily by the agricultural sector. However, the generalisation cannot be made that all antibiotic treatment in farm animals represents a hazard to public health [ 222 , 223 ].

The use of antibiotics in intensive livestock production is closely linked to the housing and rearing conditions of farm animals. Specific conditions for conventional livestock farming in different countries, as well as farmers’ attitudes, may differ between countries, e.g. conventional pig production at above EU animal welfare standards and farmers’ attitudes in Sweden [ 224 , 225 ]. Conventional production is typically aiming for high production levels with restricted input resources such as space, feed etc., and these conditions may cause stress in the individual animal as it is unable to cope with the situation, e.g. in pig production [ 226 , 227 ]. This means that higher stocking density, restricted space and barren environment are factors increasing the risk of the development of diseases, and therefore it is more likely that animals under these conditions need antibiotic treatments.

Organic production aims for less intensive animal production, which generally means that the animals have access to a more spacious and enriched environment, access to an outdoor range and restricted group sizes, and other preconditions [ 70 ]. This would ultimately decrease the need for preventive medication of the animals as they can perform more natural behaviours and have more opportunity to maintain a good health. However, in practice, the health status of organic livestock is complex and disease prevention needs to be adapted to the individual farm [ 228 ]. A report on the consequences of organic production in Denmark demonstrates that meeting the requirements of organic production has several positive consequences in relation to animal welfare and health [ 70 ].

According to EU regulations, routine prophylactic medication of animals in organic production is not allowed. However, diseases should be treated immediately to avoid suffering, and the therapeutic use of antibiotics is allowed, but with longer withdrawal periods than in conventional production [ 5 ]. Furthermore, products from animals treated more than three times during 12 months, or, if their productive lifecycle is less than 1 year, more than once, cannot be sold as organic [ 6 ]. This means that therapeutically the same antibiotics used in conventional farming may be used in organic farming, but under different conditions. For example, antibiotics mainly used for sub-therapeutic treatment as prophylaxis are never considered in organic production.

While the organic regulations aim for a low use of antibiotics in livestock production, the actual use of antibiotic drugs in European organic compared to conventional animal husbandry is not comprehensively documented. Scattered studies indicate that the antibiotic use generally is substantially higher in conventional compared to organic systems, especially for pigs (approximately 5 – 15-fold higher) [ 229 , 230 ]. In studies from Denmark [ 231 ] and the Netherlands [ 232 ], the antibiotic use in dairy cows was 50% and 300% higher in conventional compared to organic systems, although a Swedish study found no differences in disease treatment strategies between organic and conventional dairy farms, e.g. for mastitis [ 233 ]. While only sparingly documented (e.g. [ 234 , 235 ]), there is only little use of antibiotics in EU organic broiler production. This is a consequence of regulations prohibiting prophylactic use and prescribing long withdrawal periods before slaughter [ 6 , 236 ], in conjunction with the fact that it is not feasible to treat single animals in broiler flocks. In conventional broiler production, antibiotic use is common (e.g. [ 237 , 238 , 239 ]).

Recently, gene sequencing has revealed that the routes of transmission of resistance genes between human and farm animal reservoirs seem to be complex [ 213 , 222 , 240 ]. Nevertheless, a recent EFSA report found that “in both humans and animals, positive associations between consumption of antimicrobials and the corresponding resistance in bacteria were observed for most of the combinations investigated” [ 241 ], which has subsequently been strengthened [ 216 ]. In addition to direct transmission between animals and humans via contact or via food, resistant strains and resistance genes may also spread into the environment [ 242 ].

Previously, it has been postulated that a reduced need and use of antibiotics in organic livestock production will diminish the risk of development of antibiotic resistance [ 243 ], and this has also been demonstrated with regard to resistant E. coli in organic pigs compared to conventional pigs [ 244 ]. It has also been shown that the withdrawal of prophylactic use of antibiotics when poultry farms are converted from conventional to organic production standards leads to a decrease in the prevalence of antibiotic-resistant Salmonella [ 245 ].

Resistant bacteria may be transferred within the production chain from farm to fork [ 246 ]. It has been found that organic livestock products are less likely to harbour resistant bacteria in pork and chicken meat [ 25 ].

In pig production, particular attention has been paid to methicillin-resistant Staphylococcus aureus (MRSA), and in Dutch and German studies, for example, MRSA has been isolated in 30 and 55% respectively of all pigs tested [ 247 , 248 ]. Furthermore, it has been found that healthy French pig farmers are more likely to carry MRSA than control persons [ 249 ] and that they carry similar strains of MRSA to those found on their pig farms [ 250 ]. However, the prevalence of MRSA in pig production may differ between conventional and organic farms, and in a meta-study in 400 German fattening pig herds, the odds ratio (OR) for MRSA prevalence was 0.15 (95% CI 0.04, 0.55) in organic ( n  = 23) compared to conventional ( n  = 373) pig farms [ 248 ]. Multivariate adjustment for potential risk factors rendered this association non-significant, suggesting that it was carried by other factors, including factors that are regulated in or associated with organic production, such as non-slatted floors, no use of antibiotics, and farrow-to-finish herd types. Furthermore, even if there are considerable differences in antibiotic use between countries, it has been found that antibiotic resistance is less common in organic pigs compared to conventional pigs in France, Italy, Denmark, and Sweden [ 251 , 252 ].

Although it is rare for conventional farms to adopt knowledge about management and housing from organic production except when converting farms in line with organic standards, there may be options to improve animal health and welfare by knowledge transfer to conventional farms in order to reduce the use of antibiotics [ 253 ].

Within organic production, labelling requires full traceability in all steps in order to guarantee the origin of the organic products being marketed [ 5 ]. Application of the general principle of organic regulations about transparency throughout the food chain can be used to mitigate emerging problems of transmission of antimicrobial resistance. However, transition to organic production for the whole livestock sector would, on its own, be only part of a solution to the antibiotics resistance issue, because factors outside animal production, such as their use in humans, will be unaffected.

An assessment of the human health effects associated with diets based on organic food production must rely on two sets of evidence. The first set of evidence is the epidemiological studies comparing population groups with dietary habits that differ substantially in regard to choices of organic v. conventional products. These studies are to some extent complemented by experimental studies using animal models and in vitro models. The second set of data relies on indirect evidence such as chemical analyses of food products and their contents of nutrients and contaminants or antibiotic use and resistance patterns, in onsequence of agricultural production methods. Both sets of results are associated with certain strengths and weaknesses.

The few human studies that have directly investigated the effects of organic food on human health have so far yielded some observations, including indications of a lower risk of childhood allergies, adult overweight/obesity [ 18 , 46 ] and non-Hodgkin lymphoma (but not for total cancer) [ 37 ] in consumers of organic food. Owing to the scarcity or lack of prospective studies and the lack of mechanistic evidence, it is presently not possible to determine whether organic food plays a causal role in these observations. However, it has also been observed that consumers who prefer organic food have healthier dietary patterns overall, including a higher consumption of fruit, vegetables, whole grains, and legumes and a lower consumption of meat [ 18 , 29 , 37 ]. This leads to some methodological difficulties in separating the potential effect of organic food preference from the potential effect of other associated lifestyle factors, due to residual confounding or unmeasured confounders. These dietary patterns have in other contexts been associated with a decreased risk of several chronic diseases, including diabetes and cardiovascular disease [ 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. It is therefore expected that consumers who regularly eat organic food have a decreased risk of these diseases compared to people consuming conventionally-produced food, as a consequence of dietary patterns. These dietary patterns appear also to be more environmentally sustainable than average diets [ 254 ].

Food analyses tend to support the notion that organic foods may have some health benefits. Consumers of organic food have a comparatively low dietary exposure to pesticides. Although chemical pesticides undergo a comprehensive risk assessment before market release in the EU, there are important gaps in this risk assessment. In some cases, specifically for cognitive development during childhood as an effect of organophosphate insecticide exposure during pregnancy, epidemiological studies provide evidence of adverse effects [ 140 , 255 ]. Organic agriculture allows for lower pesticide residues in food and may be instrumental in conventional agriculture’s transition towards integrated pest management by providing a large-scale laboratory for non-chemical plant protection.

This review emphasizes that pesticide exposure from conventional food production constitutes a main health concern. A key issue that has only recently been explored in biomedical research is that early-life exposure is of major concern, especially prenatal exposure that may harm brain development. Most insecticides are designed to be toxic to the insect nervous system, but many higher species depend on similar neurochemical processes and may therefore all be vulnerable to these substances [ 129 ]. Besides insecticides, experimental studies suggest a potential for adverse effects on the nervous system for many herbicides and fungicides as well [ 99 ]. However, no systematic testing is available since testing for neurotoxicity – especially developmental neurotoxicity – has not consistently been required as part of the registration process, and allowable exposures may therefore not protect against such effects. At least 100 different pesticides are known to cause adverse neurological effects in adults [ 129 ], and all of these substances must therefore be suspected of being capable of damaging also developing brains. The need for prevention of these adverse outcomes is illustrated by the recent cost calculations [ 140 ] and the additional risk that pesticide exposures may lead to important diseases, such as Parkinson’s disease, diabetes and certain types of cancer.

The outcomes in children and adults and the dose-dependences are still incompletely documented, but an additional limitation is the lack of exposure assessments in different populations and also their association with dietary habits. The costs from pesticide use in regard to human health and associated costs to society are likely to be greatly underestimated due to hidden and external costs, as recently reviewed [ 256 ]. Also, gaps in the regulatory approval process of pesticides may lead to important effects being disregarded and remaining undetected.

In regard to nutrients, organic dairy products, and probably also meat, have an approximately 50% higher content of omega-3 fatty acids compared to conventional products. However, as these products only are a minor source of omega-3 fatty acids in the average diet, the nutritional significance of this effect is probably low (although this has not been proven). The nutritional content of crops is largely unaffected by the production system, according to current knowledge. Vitamins and minerals are found in similar concentrations in crops from both systems. One exception is the increased content of phenolic compounds found in organic crops, although this is still subject to uncertainty despite a large number of studies that have addressed this issue. Accordingly, although in general being favourable for organic products, the established nutritional differences between organic and conventional foods are small, and strong conclusions for human health cannot currently be drawn from these differences. There are indications that organic crops contain less cadmium compared to conventional crops. This is plausible, primarily because mineral fertiliser is an important source of cadmium in soils. However, notably, long-term farm pairing studies or field trials that are required for definitely establishing or disproving this relationship are lacking. Owing to the high relevance of cadmium in food for human health, this lack of research constitutes an important knowledge gap.

With respect to the development of antibiotic resistance in bacteria, organic animal production may offer a way of restricting the risks posed by intensive production, and even decreasing the prevalence of antibiotic resistance. Organic farm animals are less likely to develop certain diseases related to intensive production compared to animals on conventional farms. As a consequence, less antibiotics for treating clinical diseases are required under organic management, where their prophylactic use also is strongly restricted. This decreases the risk for development of antibiotic resistance in bacteria. Furthermore, the transparency in organic production may be useful for acquiring knowledge and methods to combat the rising issues around transmission of antimicrobial resistance within food production.

It appears essential that use of antibiotics in animal production decreases strongly or completely ceases in order to decrease the risk of entering a post-antibiotic era. The development and upscaling of rearing systems free or low in antibiotic use, such as organic broiler production, may be an important contribution of organic agriculture to a future sustainable food system.

Most of the studies considered in this review have investigated the effects of agricultural production on product composition or health. Far less attention has been paid to the potential effects of food processing. Processing may affect the composition of foods and the bioavailability of food constituents. It is regulated [ 5 ] and recognised [ 257 ] that food additives are restricted for organic products compared to conventional products. It is also recognised that the degree of food processing may be of relevance to human health [ 258 , 259 ]. In organic food processing, the processing should be done “with care, preferably with the use of biological, mechanical and physical methods” [ 5 ] but there are no specific restrictions or guidelines. With the exception of chemical additives, it is unknown whether certain food processing methods (e.g. fermentation of vegetables, pasteurisation of vegetables) are more prevalent in organic or conventional products or consumption patterns, or whether such differences are of relevance to human health.

The scopes of two recent reports, from Norway [ 260 ] and Denmark [ 70 ], in part overlap with the present work. Broadly, the reviewed results and conclusions presented in those reports are in line with this article. For several topics, important new evidence has been published in recent years. Consequently, in some cases stronger conclusions can be drawn today. Furthermore, the present review includes epidemiological studies of pesticide effects in the evidence base reviewed.

Over all, the evidence available suggested some clear and some potential advantages associated with organic foods. The advantages in general do not necessarily require organic food production as strictly defined in current legislation. Certain production methods, such as changes in the use of pesticides and antibiotics, can be implemented in conventional production, e.g. supporting a development towards a sustainable use of pesticides [ 261 ]. Thereby, practices and developments in organic agriculture can have substantial public health benefits also outside the organic sector.

Diet choices and the associated food production methods also have important impacts on environmental sustainability [ 254 ]. Consumption patterns of consumers preferring organic food [ 16 , 18 , 19 , 37 , 47 ] seem to align well with sustainable diets [ 2 ]. These consumption patterns also show some similarities with the Mediterranean Diet [ 262 , 263 , 264 , 265 ] and with the New Nordic Diet [ 266 , 267 , 268 , 269 ], with lower dietary footprints in regard to land use, energy and water consumption, and greenhouse gas emissions compared to concurrent average diets. Further evaluation is needed to assess the extent to which organic food systems can serve as example of a sustainable food systems [ 270 ].

For the development of healthy and environmentally-sustainable food systems in the future, production and consumption need to be considered in an integrated manner [ 2 , 271 ]. While an evaluation of overall impacts of different food systems on environmental sustainability would be highly desirable [ 270 ], the present review has attempted to assess the human health issues in regard to organic production methods and consumer preferences for organic food, both important aspects of sustainability.

Conclusions

Suggestive evidence indicates that organic food consumption may reduce the risk of allergic disease and of overweight and obesity, but residual confounding is likely, as consumers of organic food tend to have healthier lifestyles overall. Animal experiments suggest that growth and development is affected by the feed type when comparing identically composed feed from organic or conventional production. In organic agriculture, the use of pesticides is restricted, and residues in conventional fruits and vegetables constitute the main source of human exposures. Epidemiological studies have reported adverse effects of certain pesticides on children’s cognitive development at current levels of exposure, but these data have so far not been applied in the formal risk assessments of individual pesticides. The nutrient composition differs only minimally between organic and conventional crops, with modestly higher contents of phenolic compounds in organic fruit and vegetables. There is likely also a lower cadmium content in organic cereal crops. Organic dairy products, and perhaps also meats, have a higher content of omega-3 fatty acids compared to conventional products, although this difference is of likely of marginal nutritional significance. Of greater concern is the prevalent use of antibiotics in conventional animal production as a key driver of antibiotic resistance in society; antibiotic use is less intensive in organic production. Thus, organic food production has several documented and potential benefits for human health, and wider application of these production methods also in conventional agriculture, e.g., in integrated pest management, would therefore most likely benefit human health.

Abbreviations

3-phenoxybenzoic acid

Attention deficit hyperactivity disorder

Acceptable daily intake

Acceptable operator exposure level

Acute reference dose

Body mass index

Bovine spongiform encephalopathy

Center for the health assessment of mothers and children of Salinas

Confidence interval

Dialkyl phosphate

Dichlorodiphenyltrichloroethane

Deoxynivalenol

Escherichia coli

European Economic Area

European Food Safety Authority

European Union

Food and Agriculture Organization of the United Nations

Hazard index

Immunoglobulin G

Integrated pest management

Intelligence quotient

Maximum residue level

Methicillin-resistant Staphylococcus aureus

National health and nutrition examination survey

Ochratoxin A

Persistent, bioaccumulative, toxic

Perturbateurs endocriniens: étude longitudinale sur les anomalies de la grossesse, l’infertilité et l’enfance (endocrine disruptors: longitudinal study on disorders of pregnancy, infertility and children)

Polyunsaturated fatty acid

Relative risk

Standardized mean difference

Tolerable daily intake

United Kingdom

United States

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Acknowledgements

The present review was initiated after a workshop entitled “The impact of organic food on human health” organized by the European Parliament in Brussels, Belgium on 18 November 2015, in which several of the authors participated, and which resulted in a formal report to the European Parliament [ 199 ]. The present review is an updated and abbreviated version aimed for the scientific community. The authors would like to thank the following colleagues for critically reading and reviewing sections of the review: Julia Baudry, Nils Fall, Birgitta Johansson, Håkan Jönsson, Denis Lairon, Kristian Holst Laursen, Jessica Perry, Paula Persson, Helga Willer and Maria Wivstad. The authors would also like to thank Marcin Barański and Gavin Stewart for providing additional meta-analyses of cadmium contents in organic and conventional crops. The STOA staff is acknowledged for organising the seminar in Brussels.

The Science and Technology Options Assessment Panel of the European Parliament provided funding for writing this paper, travel support to the authors and coverage of incidental expenses.

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Helle Raun Andersen & Philippe Grandjean

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AM, PG and GQ drafted the introduction. EKG drafted the human studies section. JK drafted the food consumption pattern aspects in the human studies section and in the discussion. AM and ER drafted the in vitro and animal studies section. HRA and PG drafted the pesticides section. AM and ER drafted the plant foods section. AM drafted the animal foods section. SG drafted the antibiotic resistance section. AM and PG drafted the discussion and conclusions. All authors commented on the entire draft and approved the final version.

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The authors have no conflict of interest to report. AM has participated as an expert witness in a court case in Sweden related to pesticide exposure from organic and conventional foods (Patent and Market Courts, case no. PMT11299–16), but did not benefit financially from this effort. PG is an editor of this journal but recused himself from participating in the handling of this manuscript.

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Mie, A., Andersen, H.R., Gunnarsson, S. et al. Human health implications of organic food and organic agriculture: a comprehensive review. Environ Health 16 , 111 (2017). https://doi.org/10.1186/s12940-017-0315-4

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Americans are divided over whether eating organic foods makes for better health

Americans are closely divided over the health benefits of organic produce. Some 45% of U.S. adults say organic fruits and vegetables are better for you than conventionally grown produce, compared with 51% who say that organic produce is neither better nor worse, according to a Pew Research Center survey conducted earlier this year. The share of U.S. adults who say that organic produce is better for one’s health declined by 10 percentage points since a 2016 survey .

However, younger people remain more likely than their older counterparts to say organics are healthier than conventionally grown food. Some 54% of those ages 18 to 29 and 47% of those ages 30 to 49 believe organic fruits and vegetables are generally better for one’s health, compared with 39% of those 65 and older who say the same. As in the 2016 survey, there are no differences among men and women on views of the healthfulness of organic foods.

These latest findings come as consumers sort through ongoing public debates over how the foods we eat can affect our health. Today, the perception of what constitutes a “healthy” diet can be in the eye of the beholder, as even the U.S. Food and Drug Administration wrestles with new guidelines for which food products can legally have “healthy” printed on their labels.

About four-in-ten U.S. adults (39%) estimate that most (7%) or some (32%) of the food they eat is organic. A majority of this group (68%) believes that organic fruits and vegetables are better for health than conventionally grown options. By comparison, 32% of those who report eating no organic foods or not too much believe that organic produce is better for one’s health.

Organic farming strives to eliminate the use of conventional pesticides and fertilizers so that fruits, vegetables and grains have substantially lower levels of those chemicals. Farmers also pledge that organic crops are not genetically modified (GM).

The retail value of organic produce has prompted some importers to attach fake organic labels to produce. Some farmers worry that such scams, along with new efforts at government deregulation , could chip away at public confidence that foods labeled “organic” are truly what they say they are.

Americans who estimate that most or some of their diet is organic tend to have different beliefs about food than those who don’t eat very much organics. Six-in-ten U.S. adults who estimate that most or some of their diet is organic believe GM foods are worse for your health than foods with non-GM ingredients. This compares with 43% among those who report eating no organic foods or not too much.

Also, a majority of people (65%) who estimate that most or some of their diet is organic believe that food additives pose a serious risk to health over a person’s lifetime, versus 41% among those who report eating no organic foods or not too much.

More specifically, 42% of U.S. adults who say most or some of the food they eat is organic believe that eating fruits and vegetables grown with pesticides has a great deal of health risk for the average person over their lifetime. In comparison, just 25% of those who eat not too much or no organic food share that view.

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Little evidence of health benefits from organic foods, study finds

September 3, 2012 - By Michelle Brandt

Crystal Smith-Spangler and her colleagues reviewed many of the studies comparing organic and conventionally grown food, and found little evidence that organic foods are more nutritious.

You’re in the supermarket eyeing a basket of sweet, juicy plums. You reach for the conventionally grown stone fruit, then decide to spring the extra $1/pound for its organic cousin. You figure you’ve just made the healthier decision by choosing the organic product — but new findings from Stanford University cast some doubt on your thinking.

“There isn’t much difference between organic and conventional foods, if you’re an adult and making a decision based solely on your health,” said Dena Bravata , MD, MS, the senior author of a paper comparing the nutrition of organic and non-organic foods, published in the Sept. 4 issue of Annals of Internal Medicine .

A team led by Bravata, a senior affiliate with Stanford’s Center for Health Policy , and Crystal Smith-Spangler , MD, MS, an instructor in the school’s Division of General Medical Disciplines and a physician-investigator at VA Palo Alto Health Care System , did the most comprehensive meta-analysis to date of existing studies comparing organic and conventional foods. They did not find strong evidence that organic foods are more nutritious or carry fewer health risks than conventional alternatives, though consumption of organic foods can reduce the risk of pesticide exposure.

The popularity of organic products, which are generally grown without synthetic pesticides or fertilizers or routine use of antibiotics or growth hormones, is skyrocketing in the United States. Between 1997 and 2011, U.S. sales of organic foods increased from $3.6 billion to $24.4 billion, and many consumers are willing to pay a premium for these products. Organic foods are often twice as expensive as their conventionally grown counterparts.

Although there is a common perception — perhaps based on price alone — that organic foods are better for you than non-organic ones, it remains an open question as to the health benefits. In fact, the Stanford study stemmed from Bravata’s patients asking her again and again about the benefits of organic products. She didn’t know how to advise them.

So Bravata, who is also chief medical officer at the health-care transparency company Castlight Health, did a literature search, uncovering what she called a “confusing body of studies, including some that were not very rigorous, appearing in trade publications.” There wasn’t a comprehensive synthesis of the evidence that included both benefits and harms, she said.

“This was a ripe area in which to do a systematic review,” said first author Smith-Spangler, who jumped on board to conduct the meta-analysis with Bravata and other Stanford colleagues.

For their study, the researchers sifted through thousands of papers and identified 237 of the most relevant to analyze. Those included 17 studies (six of which were randomized clinical trials) of populations consuming organic and conventional diets, and 223 studies that compared either the nutrient levels or the bacterial, fungal or pesticide contamination of various products (fruits, vegetables, grains, meats, milk, poultry, and eggs) grown organically and conventionally. There were no long-term studies of health outcomes of people consuming organic versus conventionally produced food; the duration of the studies involving human subjects ranged from two days to two years.

After analyzing the data, the researchers found little significant difference in health benefits between organic and conventional foods. No consistent differences were seen in the vitamin content of organic products, and only one nutrient — phosphorus — was significantly higher in organic versus conventionally grown produce (and the researchers note that because few people have phosphorous deficiency, this has little clinical significance). There was also no difference in protein or fat content between organic and conventional milk, though evidence from a limited number of studies suggested that organic milk may contain significantly higher levels of omega-3 fatty acids.

The researchers were also unable to identify specific fruits and vegetables for which organic appeared the consistently healthier choice, despite running what Bravata called “tons of analyses.”

“Some believe that organic food is always healthier and more nutritious,” said Smith-Spangler, who is also an instructor of medicine at the School of Medicine. “We were a little surprised that we didn’t find that.”

The review yielded scant evidence that conventional foods posed greater health risks than organic products. While researchers found that organic produce had a 30 percent lower risk of pesticide contamination than conventional fruits and vegetables, organic foods are not necessarily 100 percent free of pesticides. What’s more, as the researchers noted, the pesticide levels of all foods generally fell within the allowable safety limits. Two studies of children consuming organic and conventional diets did find lower levels of pesticide residues in the urine of children on organic diets, though the significance of these findings on child health is unclear. Additionally, organic chicken and pork appeared to reduce exposure to antibiotic-resistant bacteria, but the clinical significance of this is also unclear.

As for what the findings mean for consumers, the researchers said their aim is to educate people, not to discourage them from making organic purchases. “If you look beyond health effects, there are plenty of other reasons to buy organic instead of conventional,” noted Bravata. She listed taste preferences and concerns about the effects of conventional farming practices on the environment and animal welfare as some of the reasons people choose organic products.

“Our goal was to shed light on what the evidence is,” said Smith-Spangler. “This is information that people can use to make their own decisions based on their level of concern about pesticides, their budget and other considerations.”

She also said that people should aim for healthier diets overall. She emphasized the importance of eating of fruits and vegetables, “however they are grown,” noting that most Americans don’t consume the recommended amount.

In discussing limitations of their work, the researchers noted the heterogeneity of the studies they reviewed due to differences in testing methods; physical factors affecting the food, such as weather and soil type; and great variation among organic farming methods. With regard to the latter, there may be specific organic practices (for example, the way that manure fertilizer, a risk for bacterial contamination, is used and handled) that could yield a safer product of higher nutritional quality.

“What I learned is there’s a lot of variation between farming practices,” said Smith-Spangler. “It appears there are a lot of different factors that are important in predicting nutritional quality and harms.”

Other Stanford co-authors are Margaret Brandeau , PhD, the Coleman F. Fung Professor in the School of Engineering; medical students Grace Hunter, J. Clay Bavinger and Maren Pearson; research assistant Paul Eschbach; Vandana Sundaram, MPH, assistant director for research at CHP/PCOR; Hau Liu, MD, MBA, clinical assistant professor of medicine at Stanford and senior director at Castlight Health; Patricia Schirmer, MD, infectious disease physician with the Veterans Affairs Palo Alto Health Care System; medical librarian Christopher Stave, MLS; and Ingram Olkin, PhD, professor emeritus of statistics and of education. The authors received no external funding for this study.

Information about Stanford’s Department of Medicine, which supported the work, is available at http://medicine.stanford.edu . The Center for Health Policy is a unit of the Freeman Spogli Institute for International Studies at Stanford .

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Consensus on commitment and action to monitor healthy diets

• Lynnette M. Neufeld   ORCID: orcid.org/0000-0003-2652-9108 1 ,
• Edward A. Frongillo   ORCID: orcid.org/0000-0002-8265-9815 2 ,
• Jennifer C. Coates   ORCID: orcid.org/0000-0001-6510-3199 3 ,
• Victor M. Aguayo   ORCID: orcid.org/0000-0003-1825-4108 4 &
• Francesco Branca 5  

Nature Food volume  5 ,  pages 533–534 ( 2024 ) Cite this article

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Diets are not monitored towards global nutrition-related targets either, despite clear commitments to “ensure access by all people to safe, nutritious and sufficient food” explicit in Sustainable Development Goal (SDG) 2. Current SDG 2 indicators, which capture undernourishment (that is, insufficient dietary energy supply at a national level), food insecurity, and nutritional status of children and women, do little to provide insights into the population-level consumption of healthy diets.

For example, in 2017 and 2018, the prevalence of undernourishment estimates for Tajikistan and Nigeria were relatively similar (11.6% and 10.4%, respectively) (Table 1 ). However, minimum diet diversity for women (MDD-W), collected in the same years through the Demographic and Health Surveys, revealed that although 80% of women of reproductive age were reaching MDD-W in Tajikistan, only 56% of women achieved MDD-W in Nigeria. The corresponding prevalence of minimum dietary diversity for children (MDD-C) was 22.5% in Tajikistan in the same year and 31.1% in Nigeria (2021). That is, with the same national availability of dietary energy, women in Tajikistan were achieving far better dietary diversity than women in Nigeria. At the same time, less than a third of children in both countries were achieving MDD-C, but the prevalence was higher in Nigeria than in Tajikistan 4 .

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Acknowledgements

The HDMI core group acknowledges contributions to the initiative from S. Farley (the Rockefeller Foundation) and S. Sundberg (Bill & Melinda Gates Foundation). Funding for HDMI is gratefully acknowledged from the Rockefeller Foundation (organization, hosting and funding for the first group convening) and from the Bill & Melinda Gates Foundation (grant no. INV-063321) for ongoing efforts. The findings and conclusions contained within are those of the authors/contributors and do not necessarily reflect positions or policies of author’s or acknowledged individual’s affiliate organizations or funders.

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Neufeld, L.M., Frongillo, E.A., Coates, J.C. et al. Consensus on commitment and action to monitor healthy diets. Nat Food 5 , 533–534 (2024). https://doi.org/10.1038/s43016-024-01016-8

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A Comprehensive Analysis of Organic Food: Evaluating Nutritional Value and Impact on Human Health

Azizur rahman.

1 Centre for Climate Change Research, University of Toronto, ONRamp at UTE, Toronto, ON M5G 1L5, Canada; [email protected] (P.B.); [email protected] (E.H.Y.K.); moc.liamtoh@uvripaleirbag (D.G.P.); [email protected] (R.R.); [email protected] (M.A.); ac.hcraeseregnahcetamilc@normis (S.P.)

2 A.R. Environmental Solutions, ICUBE-University of Toronto, Mississauga, ON L5L 1C6, Canada

Parnian Baharlouei

3 Physiology and Human Biology, University of Toronto, Toronto, ON M5S 1A8, Canada

Eleanor Hui Yan Koh

Diana gabby pirvu, rameesha rehmani, mateo arcos, simron puri.

In recent years, organic agriculture has gained more popularity, yet its approach to food production and its potential impact on consumers’ health and various environmental aspects remain to be fully discovered. The goal of organic farming practices is to maintain soil health, sustain ecological systems, maintain fairness in its relationship with the environment and protect the environment in its entirety. Various health benefits have been associated with higher consumption of organic foods. This review identified some of these health benefits, including a reduction in obesity and body mass index (BMI), improvements in blood nutrient composition as well as reductions in maternal obesity and pregnancy-associated preeclampsia risks. Furthermore, organic food consumption can reduce the development of non-Hodgkin lymphoma (NHL) and colorectal cancers. Upon reviewing the existing literature regarding the nutritional value of organic foods, it was found that organic food contained higher levels of iron, magnesium and vitamin C. However, the evidence available to draw definitive causations remains limited due to study biases, short study durations and confounding variables; thus, it cannot be concluded that the organic diet provides any related health benefits. In this review, we provided essential insights and statistical analysis from the evidence available and consider study limitations to evaluate the potential of organic food consumption in positively impacting human health.

1. Introduction

Organic farming is designed to mitigate environmental pollution and prioritize animal welfare through protective management strategies that prevent exposure to harmful pesticides, industrial solvents and synthetic chemicals [ 1 , 2 ]. However, this system of management goes beyond avoiding the use of synthetic inputs by basing its practices on four principles: health, ecology, fairness and care [ 3 , 4 ]. The principle of health ensures that organic agriculture should sustain and strengthen the health of the soil, plants, animals, humans and the earth as a whole [ 3 ]. The principle of ecology focuses on living ecological systems and how organic agriculture should work with, sustain and emulate these systems [ 3 , 5 ]. The principle of fairness underscores the importance of relationships ensuring fairness in the common environment and life opportunities [ 3 ]. Finally, the principle of care advocates for safe and responsible agricultural management to protect current and future generations and the environment [ 3 ]. To adhere to these principles, organic farming employs practices such as crop rotation, intercropping, polyculture, covering crops, seeding timing and mulching [ 3 ]. Notably, the increasing awareness and demand for organic food in recent years are attributed to its perceived health benefits and positive impact on environmental biodiversity [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].

The primary motivation for purchasing organic food is its perceived health benefits, followed by considerations for ecosystems and the environment [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Consequently, the global organic food market has experienced rapid growth, with an estimated 10% increase since 2000 [ 18 ]. Since then, the organic food production market was valued at CAD 7 billion in 2020 and organic packaged food sales are projected to reach USD 1.6 billion by 2025 [ 19 ]. Considering the rapidly growing demand for healthy, environmentally conscious foods, it is important to explain how public perception of the organic diet has influenced its surge in popularity.

Generally, several reports have uncovered that consumers who strictly follow an organic diet do so for one of several reasons: perceived health benefits, concern for the environment and the inherent value of buying local [ 11 , 15 , 16 , 17 , 19 , 20 ]. Health-conscious consumers are more likely to avoid mainstream products containing pesticides, hormones, and other additives, instead opting for organic alternatives that are marketed as natural and chemical-free [ 15 , 16 ]. Correspondingly, Rana and Paul discovered that Canadians placed a lot of value on the certification and labeling of the organic packaged goods they were buying [ 21 ]. Comparatively, concerns about accessibility, safety, and price were predominant in Slovenia, Portugal and China [ 21 ]. Some Canadian organic consumers even had preferences for particular organic certificates and commonly sought information about the product’s origins and the production methods used [ 21 ]. Thus, consumer trust in the product they are purchasing heavily influences their decision to buy organic [ 11 , 12 , 13 , 15 , 19 , 20 , 21 ].

Conversely, the higher cost, lack of widespread availability and lack of perceived value were all reported to be factors that deterred consumers from purchasing organic foods [ 15 , 19 , 20 , 21 ]. Previous studies have discovered that organic foods are on average 10% to 40% more expensive than conventionally produced foods [ 22 ]. Further on, a 2021 online survey of up to 187,000 Canadians demonstrated that 18% of respondents believed organic foods were no different from mainstream products [ 19 ], possibly because the evidence surrounding their health benefits remains ambiguous.

Considering affordability and perceived value majorly influence purchasing decisions, higher income levels often correlate with an increased likelihood of purchasing organic foods [ 13 , 21 , 22 ]. In addition, higher levels of education are associated with greater awareness of health and environmental concerns related to food choices [ 13 ]. Educated consumers may be more informed about the benefits of organic farming practices and choose organic products accordingly. A recent study investigating the organic purchasing intentions of Bangladeshi consumers uncovered a significant positive correlation between the level of education and the intention to purchase sustainable organic food. Specifically, the study found a 3.27-fold increase in organic food purchasing among consumers with higher levels of education [ 13 ]. Other socio-economic factors that may influence organic purchasing decisions include age and gender, cultural dietary habits and health and wellness trends in the market [ 11 , 12 , 13 , 14 , 15 , 16 , 20 , 21 ]. For example, the same study demonstrated that Hungarians and Swiss people over the age of fifty are more price sensitive [ 13 ]. In addition, some cultural or ethnic groups may have traditions or preferences for specific types of organic produce or traditional farming methods, such that individuals with specific health concerns or dietary preferences may opt for organic options. Finally, growing health consciousness and a focus on wellness can drive the demand for organic foods perceived as healthier and free from synthetic chemicals [ 13 , 14 , 15 ]. Figure 1 , taken from Statista 2021 [ 19 ], further breaks down the surveyed consumers’ attitudes toward organic products and provides further insights into how organic food is perceived in Canada.

Breakdown of opinions on organic food in Canada. Data collected from a 2021 online survey of up to 187,000 Canadians over 18 years of age [ 19 ].

This review article aims to elucidate key impacts of organic agriculture on human health and provide insights into current market trends. Given that food safety is a pivotal determinant influencing consumer choices [ 23 ], our investigation focuses on exploring the ramifications of embracing organic farming practices to ascertain whether such practices can indeed yield favorable health outcomes for organic consumers. Our analysis encompasses an examination of findings from various studies conducted over the past 25 years, combining original research and cohort studies sourced from public literature to present a comprehensive overview of the potential impact of organic food consumption on human health.

2. Organic versus Conventional Food

The production of organic food requires special considerations ( Figure 2 ). Generally, organic farming is solely grounded in biological and ecological processes that mitigate the environmental impact of agricultural practices while preserving the natural qualities of food [ 10 , 24 ]. In this holistic approach, pest and disease control are achieved naturally, eliminating the need for synthetic chemicals utilized in conventional farming [ 24 , 25 ]. Additionally, organic food must not be sourced from genetically modified organisms (GMOs) [ 24 , 26 ]. Organic farming also relies on mechanical weeding as an alternative to traditional herbicide input, potentially leading to increased weed cover that benefits various organisms by promoting biodiversity [ 26 ]. Core principles of organic agriculture, such as the use of green manure, crop diversification, and small fields, further contribute to the production system’s sustainability [ 26 ]. Following these principles, organic farming is believed to enhance soil fertility and foster biodiversity. Studies indicate that local species richness and abundance can increase by approximately 34% and 50%, respectively, across various crops worldwide compared to conventional farming practices [ 26 ]. Thus, there has been a recent upsurge in both the production and purchasing of organic goods, driven by a heightened demand for natural products that undergo minimal processing and abstain from synthetic and artificial fertilizers or pesticides in their production processes [ 27 , 28 ].

Organic crop farming at a glance [ 29 , 30 , 31 , 32 , 33 ].

Unlike conventional farming, organic farming does not use genetic engineering or synthetic pesticides in the food production process, allowing for an assessment of their health effects. The use of genetic engineering and GMOs can pose various health risks, such as allergic reactions and unexpected interlinks between genes due to gene additions and modifications [ 31 ]. Moreover, pesticides utilized in agriculture can accumulate in soil and water, quickly entering the food chain and impacting human health [ 32 ]. These health effects span from allergic reactions to lung damage, causing breathing difficulties, nervous system problems, birth defects, and the risk of chronic diseases such as cancer [ 32 ]. For instance, the organochlorine insecticide (OCI) dichlorodiphenyltrichloroethane (DDT) functions by opening sodium channels in the human nervous system, leading to increased firing of action potentials that can result in spasms and, in severe cases, death [ 34 , 35 ]. Conversely, carbamate insecticides inhibit the acetylcholinesterase enzyme, interfering with cell replication and differentiation, proper synapse signaling, and other neurotoxic effects [ 34 , 36 ]. Furthermore, the growth regulator herbicide 2,4-D, used to eliminate weeds, has been linked to severe eye irritations and fertility problems in men [ 34 ]. Studies have also associated anilide/aniline herbicides with risks of colon and rectal cancer [ 34 ]. Glyphosate, a common ingredient in pesticides found in GM crops, has also been linked to cancer risks, especially non-Hodgkin lymphoma (NHL) [ 31 ]. Glyphosate was first used as a broad-spectrum pesticide in 1974 [ 37 ]. As genetically engineered glyphosate-tolerant crops were introduced, glyphosate quickly spread worldwide and has now become the most widely used pesticide in agricultural and residential sectors [ 37 ]. However, glyphosate is an organophosphorus compound which interferes with aromatic amino acid synthesis through a mechanism unique to plants [ 37 ]. Thus, concerns have arisen about glyphosate’s potential genotoxicity through the induction of oxidative stress for human cells in vitro and in animal experiments [ 37 ]. A 2021 review on the health effects of glyphosate stated a clear association between glyphosate exposure and a wide range of human diseases, including gut microbiota dysbiosis, kidney and liver damage and neurological conditions such as Alzheimer’s [ 38 ].

It is important to note that a majority of these experiments tested much higher doses than those permitted for agricultural use. Notably, esteemed institutions such as the Food and Agriculture Organization (FAO), the European Chemicals Agency (ECHA) and the European Food Safety Authority (EFSA) have affirmed glyphosate’s status as non-toxic and non-carcinogenic to human target organs as of 2022 [ 38 ]. In rabbit studies conducted by the EFSA, an acceptable daily intake (ADI) of 0.5 mg/kg of body weight per day was defined, while the FAO and WHO established an acute toxicity measure (LD50) of 5600 mg/kg of body weight for the oral pathway and over 2000 mg/kg of body weight for the dermal pathway [ 38 ]. Consequently, the commercialization of glyphosate-based herbicides (GBHs) is subject to stringent regulations, including the establishment of maximum residue limits (MRLs) for glyphosate residues in various food items. Despite these regulations, an EFSA multinational study identified glyphosate in 24 out of 186 honey samples, with 8 surpassing legal limits ( Table 1 ) [ 38 ]. Approximately 30% of honey samples in the USA contained glyphosate residues, with over half exceeding MRLs—including one sample that was seven times higher than the allowed limit ( Table 1 ) [ 38 ]. Further on, studies in Canada and Switzerland found detectable levels of glyphosate in nearly all samples, although concentrations remained below the MRL of 50 μg/kg [ 38 ].

The frequency of glyphosate detection in honey samples from different countries; nd = no data [ 38 ].

Considering the MRL for pesticides is typically determined through testing individual pesticides on rats for a relatively brief duration, there is a substantial lack of knowledge regarding the consequences of consuming potentially hundreds of different pesticides over one’s lifetime. The intricate interplay of these various pesticides remains largely unknown. Thus, further research is needed to uncover the cumulative long-term health effects of glyphosate and other pesticide residues, as many studies reveal a variety of toxic effects [ 38 ]. As a result, pesticide use may adversely affect human cells through mechanisms still unclear, and it may be possible to minimize these health risks by re-orienting agricultural practices toward more organic approaches.

2.1. Nutritional Benefits

The nutrient and mineral content of crops is affected by various agronomic factors including fertilization type, crop rotation designs and crop protection protocols [ 24 , 39 ]. For example, the addition of organic matter to soil helps provide food for beneficial plant microorganisms, and in return, these stimulated microorganisms produce valuable compounds (including citrate and lactate) that make soil minerals more available to organic plant roots [ 39 ]. In addition, organic farming allows for the slow release of soil minerals over time, causing essential nutrients to become available when needed, whereas chemical fertilizers quickly dissolve in irrigation water and deliver excess quantities of nutrients to crops, often past what is needed [ 39 ]. Thus, agronomic differences in organic versus conventional farming systems may impact the quantity and quality of beneficial compounds that can be obtained from each crop type [ 24 , 39 ]. However, studies comparing the nutrient content between organic and conventional crops have revealed inconsistent results [ 24 ]. Further on, many of these studies lack the necessary control factors to validate the results, such as failing to consider the different environmental and growing conditions that affect crop quality [ 24 ]. In 2012, Smith-Spangler et al. [ 29 ] reviewed the results of 223 studies examining the nutrient content of organic foods, including ascorbic acid, phosphorus, calcium, magnesium, iron and various vitamins. The findings showed that organic fruits, vegetables, and grains do not exhibit significantly higher nutrient levels compared with their non-organic counterparts. However, organic produce did show higher levels of phosphorus when compared with non-organic produce [ 29 ]. All in all, the evidence was not strong enough to suggest that organic foods are more nutritious than non-organic foods. However, further recent experiments [ 40 , 41 , 42 , 43 ] have demonstrated that some organic foods, such as corn grain, wheat flour, broccoli, tomato, black sesame and leafy vegetables, contain more minerals and vitamins, which are discussed below.

2.2. Mineral Content

The most essential minerals are calcium, magnesium, potassium, iron, zinc, copper, manganese, selenium and iodine [ 40 ]. Studies have shown that the content of these minerals in fruits, especially apples, does not differ significantly between organically grown and conventional methods [ 40 , 41 ]. Studies on organic vegetables, however, revealed higher levels of iron and magnesium compared to conventionally grown vegetables. Overall, Worthington revealed that the iron and magnesium content in organic crops was higher by 21% and 29%, respectively [ 39 ]. Moreover, a study by Yu et al. [ 42 ] demonstrated 20% higher magnesium content and 30% higher phosphorus and potassium contents in organic compared to conventionally grown summer corn. However, the study did not provide details on methodologies or sample sizes, thereby limiting the credibility of the reported data. They also found higher levels of zinc and iron in organic corn, but this increase was not significant [ 42 ]. These findings were further compounded by Rembialkowska [ 43 ], where the results of many experiments demonstrated a higher level of iron, phosphorous and magnesium content in organically grown compared to non-organically grown products. These results may be attributed to the effects of traditional potassium fertilizers used in conventional agriculture, which can decrease the amount of magnesium—and consequently, phosphorus—absorbed from soils [ 39 ]. Further on, organic fertilizers tend to increase the number of soil microorganisms that affect various components of plant nutrient acquisition and metabolism, which may play an essential role in making iron more bioavailable to plant roots [ 39 ]. Confounding factors, including variations in soil fertility, pH levels and the presence of specific minerals across different plots and geographical regions, can significantly influence the absorption and availability of nutrients for plants [ 39 ]. Consequently, any observed differences in the nutritional content of organic and conventional produce may be attributed to variations in soil conditions and cultivation practices rather than the farming methods alone. To mitigate these potential confounding variables, researchers must meticulously control and monitor soil conditions, cultivation practices and climatic variations in their study to ensure that the comparison between organic and conventional crops is not influenced by any disparities in these factors.

2.3. Vitamin Content

Experiments on the various vitamin contents of different organic versus non-organic fruits and vegetables are limited. A 2010 review on the nutritional quality of organic food revealed higher vitamin C contents in organic potatoes, tomatoes, kale and celeriac as well as higher vitamin E content in organic olive oil [ 40 ]. Similarly, Worthington’s experiment revealed 27% higher vitamin C levels in organically grown lettuce, spinach, potatoes and cabbage [ 39 ]. On the other hand, some studies on beta-carotene (vitamin A precursor) have shown that the beta-carotene content of organic foods greatly depends on the type of fertilizer used, as nitrogen fertilizers have been shown to yield higher beta-carotene levels in carrots [ 40 , 41 ]. Other experiments have shown similar outcomes in conventional agriculture, such that increased fertilization changes the content of secondary plant metabolites [ 44 ]. For example, Mozafar [ 45 ] revealed that nitrogen fertilizer used in conventional fruits and vegetables could increase the amount of beta-carotene and reduce vitamin C levels. This phenomenon can be attributed to alterations in plant metabolism observed in response to the differences between organic and conventional fertilizers. For example, when exposed to a high influx of nitrogen, plants tend to increase protein production while diminishing carbohydrate production, ultimately leading to a reduction in vitamin C synthesis [ 39 ]. Consequently, the vitamin content in crops is significantly influenced by the specific agronomic factors associated with each farming system.

2.4. Other Compounds

Oxidation of phenolic compounds by the polyphenol oxidase (PPO) enzyme is part of the plant antioxidant defense mechanism (to repair injuries on their surface). Phenolic compounds act as a chemical barrier against invading pathogens. Intact antioxidant defense in plants has been shown to have important implications for human health, including playing an anticarcinogenic role [ 42 ]. Organic cultivation operations have been revealed to increase the polyphenol content of peaches and pears as compared with their conventional counterparts [ 9 ]. Moreover, increased activity of the PPO enzyme towards chlorogenic and caffeic acids (antioxidant agents) was observed to be notably higher in the organic samples of peaches and pears [ 9 ]. Overall, various studies on organic crops have observed between 18% and 69% increased antioxidant activity in these products [ 46 ]. Intake of antioxidants and phenolic compounds from food consumption is important because these compounds have been shown to effectively reduce the risk of chronic diseases, including some neurodegenerative and cardiovascular diseases and cancer [ 46 ].

Another organic compound that has increased in quantities within organic foods is salicylic acid. Salicylic acid is a metabolic component of aspirin and has a high anti-inflammation capacity [ 47 ], and its intake from dietary sources has beneficial health effects. Aspirin and its metabolites, including salicylic acid, can reduce the risk of cardiovascular diseases and reduce up to 40% of the risk of colorectal cancers [ 48 ]. Relevantly, organic practices have been shown to increase the salicylic acid content of vegetable soups in comparison to their conventional counterparts [ 47 ], as displayed in Table 2 [ 42 , 47 ].

Comparative analysis of nutrient and salicylic acid content in organic and conventional food products [ 42 , 47 ].

Importantly, organic foods also demonstrated lower levels of toxic metabolites, such as cadmium and pesticide residues [ 49 ]. Cadmium is a heavy metal that is known to accumulate in the body and exert toxic effects on the kidneys and liver [ 49 ]. Importantly, eight meta-analyses conducted by Barański et al. revealed that organic crops contained on average 48% lower cadmium concentrations than conventional crops [ 49 ]. Further on, the frequency of detectable pesticide residues was four times lower in organic crops, whereas the frequency of phenolic (antioxidant) compounds was on average 20–40% and, in some cases, over 60% higher in organic crops [ 49 ]. The study analyzed a comprehensive dataset comprising 343 peer-reviewed publications, where notable discrepancies emerged across different crop types, crop species, and studies conducted in countries with different climates, soil types and agronomic backgrounds. Thus, potential limitations of these meta-analyses include variations in study methodologies and geographical locations that confound the observed results. However, by employing the GRADE (Grading of Recommendations, Assessments, Development, and Evaluation) assessment to gauge the strength of evidence for a standard weighted meta-analysis, the overall strength of evidence was deemed moderate or high for the majority of parameters where significant differences were identified (i.e., many phenolic compounds, cadmium and pesticide residues) [ 49 ].

Accordingly, a French BioNutriNet case-control study investigated the difference in urinary pesticide metabolite concentrations between 150 high-organic-food consumers and 150 low-organic-food consumers, matched for dietary patterns and other relevant traits [ 50 ]. Notably, the authors saw significant reductions of organophosphrous pesticides (OPs), diethyl-thiophosphates, dimethylthiophosphase, dialkylphosphates (DAPs) and free 3-phenoxybenzoic acid in the high-organic-consumer group, ranging from –17% to –55% reductions compared to the low-consumption group [ 50 ]. These differences were attributed to fertilization techniques, crop protection regimens, and other agronomic factors between growing practices. For example, organic farming systems avoid the use of fertilizers produced from industrial waste, which are often the most contaminated by toxic heavy metals [ 39 ].

Together, these results indicate that it may be possible to minimize dietary cadmium and pesticide intake levels by switching to an organic diet. However, there is no evidence to suggest that non-organic foods contain significant concentrations of pesticides or toxic metals that pose a risk to human health or that reduced exposure through high organic consumption is preventative for any specific health concern. Thus, several studies have demonstrated that the nutritional contents of select organic foods significantly differ compared to conventionally grown foods ( Table 2 [ 42 , 47 ] and Table 3 [ 39 ]), although the associated health benefits of these differences are not well-established.

Comparative analysis of vitamin content in organic and conventional food products [ 39 ].

3. Impact on Human Health

The findings from clinical experiments assessing the health impact of organic food on humans are relatively limited compared to other nutritional epidemiological studies. Many of these experiments are short term and may be confounded by variations in dietary patterns and lifestyles that profoundly affect human health [ 51 ]. Notably, observational studies often lack a comprehensive examination of the various health factors that may differ between organic and non-organic food consumers, such as lifestyle choices, physical activity levels and overall dietary patterns [ 50 , 51 ]. These factors may be a source of confounding that significantly influence the health outcomes observed, precipitating the need for further longitudinal intervention studies. Nevertheless, the compounds found in organic fruits and vegetables are generally believed to promote human health and longevity [ 51 ]. Consequently, individuals who consistently consume organic food often opt for more fruits and vegetables and less meat, potentially reducing the risk of mortality and chronic diseases [ 52 , 53 , 54 , 55 , 56 , 57 ]. Additionally, research indicates that those who regularly choose organic food are more likely to be female, have higher education and income levels and maintain a healthier lifestyle by smoking less and engaging in more physical activity [ 50 , 51 , 58 , 59 ]. As a result, the dietary compositions of organic and non-organic consumers may significantly differ. This section aims to present evidence from studies that have assessed the impact of organic food on human health outcomes, with consideration for the potential biases and limitations that can affect results.

4. Epidemiological Findings Related to Human Health

4.1. bmi and obesity.

Body mass index (BMI) is a weight-to-height index that divides an individual’s weight (kg) by their height (m 2 ), providing a valuable indicator for determining obesity and overweight in adults [ 60 ]. The WHO defines obesity as a BMI equal to or greater than 30 in adults, while overweight is classified as a BMI equal to or greater than 25 in adults [ 61 ]. In a prospective cohort study conducted in 2017, the Nutri-Net Santé Cohort analyzed self-reported dietary and anthropometric data from 62,224 French participants to determine how organic food consumption affects obesity risk [ 62 ]. Participants were assigned an organic score based on their organic consumption frequency, and these scores were divided into four quartiles, with the first quartile (Q1) serving as a baseline for modelling BMI changes. Models were adjusted for several characteristics, including sex, income, energy intake and expenditure, history of disease and baseline use of dietary supplements. Upon assessing the association of the organic score with BMI change through ANCOVA, the researchers discovered a significantly positive association between high organic food consumption and a reduced risk of being overweight (OR = 0.77, 95% CI 0.68, 0.86, p < 0.0001) [ 62 ]. This association remained highly significant in a 3.1-year follow-up study that demonstrated a 37% reduced risk of obesity in the high organic consumption group [ 62 ]. Specifically, males who regularly consumed organic foods exhibited a 36% and 62% lower probability of being overweight and obese, respectively, while females who regularly consumed organic foods showed a 42% and 48% lower probability compared to non-consumers [ 62 ]. Overall, their results demonstrated a strong reduction in the risk of being overweight and obese among high-frequency organic food consumers, as depicted in Figure 3 [ 62 ]. In particular, this association was stronger in participants who reported consuming more nutritious diets, as assessed by the Programme National Nutrition Santé-guidelines score (PNNS-GS) ( Figure 3 ). Observed associations remained significant even after accounting for selection bias by inverse probability weighting. However, it is essential to acknowledge the inherent challenges in designing and conducting observational studies. The reliance on self-reported dietary and anthropometric data introduces potential recall biases, raising concerns about the accuracy and reliability of the information. These challenges should be recognized and considered when interpreting the findings from such studies.

The prospective association between the organic score in quartiles (Q) and the risk of obesity, represented as % BMI change from the first quartile (Q1, baseline = 1.0). Organic scores are stratified according to diet nutritional quality and based on a low, middle, or high Programme National Nutrition Santé guidelines score (PNNS-GS). Values are OR and 95% CI, adjusted for age, sex, month and year of inclusion, delay in follow-up, occupation, marital status, education, monthly income per unit, dietary supplement use, modified Programme National Nutrition Santé guidelines score (mPNNS-GS), principal-component-analysis-extracted dietary patterns scores, energy intake, physical activity, tobacco status and history of chronic diseases. Ref. = referent values. Taken from Kesse-Guyot et al. (2017) [ 62 ].

Another cross-sectional study by Perez-Cueto et al. was conducted to compare food-related lifestyles (FRLs) between 2437 obese and non-obese respondents in five European countries (Belgium, Denmark, Germany, Greece and Poland) [ 63 ]. According to their experiment, obese participants scored lower on most dimensions of FRL related to food quality, particularly organic products, suggesting that eating more organic products reduces obesity risk.

Furthermore, a cross-sectional BioNutriNet project [ 64 ] in France comprised of 5855 participants, including children, adolescents, and adults, assessed the relationship between organic food consumption and obesity over a one-year period. Employing a three-stage stratified random sampling approach, data on food supplement usage, dietary patterns, physical activity, sedentary behaviors, health conditions, sociodemographic traits and height and body weight measurements were collected through structured face-to-face questionnaires. The results showed that in all age groups, higher consumption frequency of organic food was associated with lower BMI and obesity—however, the strength of this relationship was reported to be small [ 64 ]. An additional study examined the association between organic food consumption and obesity risk among 37,706 Sister study participants between 2003 and 2009 [ 65 ]. The participants in the age range of 35–74 reported eating organic food (including meat, dairy and produce) never, less than half of the time, about half of the time or more than half of the time in the past 12 months. The organic diet score (ODS) was calculated based on the frequency of organic food consumption, with a higher score indicating more frequent consumption. The researchers compared BMI at the time of enrollment and over a mean 8.3-year follow-up and found not only that women who ate organic foods had lower baseline BMI but also that eating less organic food was inversely related to weight gain [ 65 ].

Overall, these studies have demonstrated the association between organic food consumption and reduced risk of obesity. However, issues regarding the validity and accuracy of self-reported data come into question. Further on, these associations cannot prove causation, as BMI is heavily influenced by overall dietary quality and other healthy lifestyle habits that frequent organic consumers are typically more conscious of. The French BioNutriNet study, among others, made efforts to address various confounding variables, including socio-economic status, energy intake and expenditure, lifestyle factors, and inherent biases in observational research. To mitigate information bias, the study assessed the convergent validity of the organic food index and objectively measured height and weight. Additionally, a comprehensive survey design was employed to ensure the representativeness of the sample and minimize selection bias. However, future work is required to investigate the influence of residual confounding factors on the observed relationship between organic food consumption and BMI, given the well-established correlation between obesity and mental health issues such as depression or drug addiction [ 64 ]. Moreover, given that the questionnaire only covered a span of a year, it is essential to acknowledge that BMI and obesity status are influenced by a nutritional history extending beyond the previous year. Therefore, further longer-term longitudinal studies are imperative to yield crucial insights into our understanding of obesity risk and organic food consumption.

4.2. Blood Composition

Clinical studies have demonstrated that individuals who consume a high amount of organic food exhibit more favorable blood compositions compared to infrequent consumers.

Notably, the Nutri-Net Santé nested case-control study also revealed higher nutritional content in the fasting blood plasma samples of frequent organic food consumers [ 50 ]. Plasma levels of magnesium, fat-soluble micronutrients (a-carotene, b-carotene, lutein and zeaxanthin), fatty acids (linoleic, palmitoleic, g-linoleic and docosapentaenoic acids) and some fatty acid desaturase indexes were found in greater concentrations in frequent organic food consumers [ 50 ]. In contrast, no measurable differences were detected for other carotenoids such as lycopene and β-cryptoxanthin, minerals iron and copper or vitamins A and E [ 50 ].

Another study investigated the effects of organic versus conventional crop fertilization and crop protection schemes on the feed and body composition, hormone balance, and immune activation of rats [ 66 ]. Significantly, organic fertilization resulted in a 16% higher white blood cell count, 2.3% higher body protein, and 33% higher plasma glucose compared to mineral fertilization [ 66 ]. Further on, feeds produced by organic fertilization increased plasma concentrations of leptin (a hormone involved in regulating energy balance) and insulin-like growth factor (IGF-1, a hormone involved in regulating cell growth and development) by 29% and 46%, respectively, but only when crops were grown under organic crop protection regimes [ 66 ]. In contrast, testosterone (Ts) concentrations (a male reproductive hormone) dropped by 45% [ 66 ]. Finally, immune reactivity tests demonstrated that spontaneous lymphocyte proliferation increased by 121% for organically fed rats (considering both organic fertilization and crop protection), whereas mitogen-induced lymphocyte proliferation decreased by 47% using organic fertilization; however, this decrease was only observed if crops were grown under conventional crop protection regimes [ 66 ]. These results—represented in Figure 4 [ 46 , 66 ]—demonstrate that agronomic practices can significantly influence hormonal and immune parameters in rats, which may in return have profound impacts on the reproductive, metabolic and immune systems of the body. However, it is important to note that the effects of potential confounding factors, such as differences in metabolite bioavailability, were not considered in this study [ 66 ]. Overall, these results indicate that high consumption of organic foods may modulate blood nutritional status, perhaps through the increased levels of carotenoids, polyphenols, antioxidants, beneficial fatty acids and other compounds in organic crops that can help regulate important metabolic and immune processes for better human health. Further dietary intervention and prospective cohort studies must be conducted to conclude that these differences in blood nutrient composition have a measurable health benefit to the organic consumer.

The effects of organic and conventional crop production on four physiological parameters in rats. Plasma concentrations of insulin-like growth factor 1 (IGF-1), testosterone (Ts), leptin and spontaneous lymphocyte proliferation (sp-LP) were measured in 24 Wistar rats after 12 weeks ( n = 24). Feeds were composed of crops produced from different organic and conventional regimes (OF = organic fertilization, CF = conventional fertilization, OP = organic crop protection, CP = conventional crop protection). Different letters above bar indicate significant difference ( p < 0.05) as determined by Tukey’s HSD test (a vs. b vs. c). Taken from Baranski et al. (2017) [ 46 ], adapted from Srednicka-Tober D et al. (2013) [ 66 ].

4.3. Health Effects Associated with Pesticides

Pesticides can interfere with several molecular pathways through various epigenetic modifications to disturb metabolic and oxidative homeostasis, activate inflammatory pathways, disrupt mitochondrial and endocrine function and dysregulate apoptosis and DNA repair [ 67 ]. For individuals exposed to significantly high pesticide concentrations, these molecular changes may aggregate and ultimately lead to an increased risk of obesity, metabolic diseases, cancers, and other chronic diseases. For example, organochlorine pesticides were widely banned following the elucidation of their etiological role in type 2 diabetes [ 67 ]. Thus, the health effects of currently authorized pesticides—including organophosphorus, pyrethroids and neonicotinoids—should be thoroughly investigated to inform guidelines on appropriate and responsible pesticide usage. Furthermore, it is important to assess whether the organic diet can reduce exposure to these pesticides and whether this reduced exposure has any benefit to human health. In this section, evidence is presented to highlight the impact of pesticide exposure on different aspects of human health, including fertility, birth outcomes and the incidence of disease.

4.4. Pregnancy-Related Health Characteristics

Nutrition during pregnancy plays a pivotal role in maternal and fetal health, as environmental contaminants in the maternal diet could affect the risk of birth defects through placental or hormonal disturbances. Simões-Wüst et al. [ 68 ] assessed the association between organic food consumption and pre-pregnancy health characteristics, revealing that mothers who consumed organic food experienced better health outcomes. These outcomes included a lower risk of overweight and obesity, a more favorable BMI before pregnancy and a lower prevalence of pregnancy-associated diabetes [ 68 ]. Furthermore, participants who consumed organic food demonstrated a lower incidence of hypertension compared to non-organic consumers, although the association with blood pressure did not appear to be linear. Notably, blood lipid analysis revealed significantly higher levels of LDL among organic consumers [ 68 ].

In a separate study, male newborns of female organic consumers were compared to those of female non-organic consumers regarding hypospadias and cryptorchidism outcomes [ 69 ]. While no meaningful association was found between cryptorchidism and organic consumption, there was a lower prevalence of hypospadias among newborns whose mothers consumed organic foods during pregnancy [ 69 ]. It is important to highlight that the study classified “organic consumers” as individuals who indicated they sometimes, often, or mostly consumed organic foods in specific categories (vegetables, fruit, bread/cereal, milk/dairy products, eggs, and meat) [ 69 ]. For women undergoing infertility treatments, the consumption of fruits and vegetables with high pesticide residues has been associated with lower success rates in achieving clinical pregnancy [ 70 ]. Chiu et al. [ 70 ] discovered that women consuming more than 2.3 servings per day of such foods had 18% and 26% lower chances of achieving clinical pregnancy and live birth, respectively. This was not significant amongst women who consumed fruits and vegetables with low pesticide residues [ 70 ].

Moreover, the reduced exposure to pesticide chemicals through the consumption of organic foods offers additional maternal and fetal health benefits. A study on the consumption frequency of organic vegetables in mid-pregnancy among Norwegian mothers demonstrated that higher consumption of organic foods is associated with a reduced chance of developing preeclampsia [ 71 ]. Preeclampsia is present among 5–8% of pregnant women and poses risks of maternal and fetal mortality, an exaggerated inflammatory immune response, and pregnancy-associated hypertension [ 72 ]. The study suggests three potential explanations for how organic food consumption reduces preeclampsia risk: decreased exposure to OP pesticides, particularly Chlorpyrifos (CPF), which can increase the permeability of gut intestinal cells to induce inflammation; ingestion of plant secondary metabolites with anti-inflammatory properties, including salicylic acid and polyphenols; and improved intestinal microbiota, resulting in an anti-inflammatory response [ 71 ].

Overall, there have been several studies that have demonstrated benefits to organic foods either in relation to consumption or the lack of exposure to pesticide chemicals. However, all of these health benefits can only be associated with, but not explained by, an increase in organic food consumption, as differences between study populations and other confounding factors may have influenced the observed results. Therefore, further research is necessary to provide a more comprehensive understanding and draw conclusive evidence regarding measurable health benefits from consuming organic foods during pregnancy.

4.5. Impact on Children’s Health

One of the main draws of the organic diet is that it claims to limit pesticide exposure, which is associated with damaging genotoxic effects including cancer-causing carcinogens and disruptions in the endocrine and nervous systems of the body [ 73 , 74 ]. The toxic effects of pesticide exposure impact fetuses and young children at key developmental stages in their life, leading to life-long effects [ 36 , 73 , 74 , 75 , 76 ]. Further on, OPs and carbamates inhibit acetylcholine breakdown—which is already decreased during pregnancy—and younger children exhibit lower levels of detoxifying enzymes compared to adults, suggesting that young children are especially susceptible to the toxic effects of pesticide exposures [ 36 ].

Indeed, the cluster-randomized crossover trial conducted by Makris et al. in 2019 demonstrated that pyrethroid and neonicotinoid pesticide metabolite concentrations were significantly lower in Cypriot children following a 40-day organic diet [ 73 ]. Importantly, this outcome was linked to a reduction in various biomarkers of oxidative stress and inflammation [ 73 ], suggesting a potential mechanism by which organic foods could confer health benefits to the consumer.

Similarly, a cross-sectional analysis of data from the National Health and Nutrition Examination Survey (2000–2004) analyzed how dietary exposure to pesticide residues affected ADHD prevalence in U.S. children [ 36 ]. The study discovered that a 10-fold increase in urinary concentrations of dimethyl alkylphosphates (OP metabolites) increased the odds of ADHD diagnosis by 55% [ 36 ], supporting the theory that OP exposure may influence neurological outcomes at levels common in U.S. children. Conversely, a large prospective birth cohort study of Mexican American children found no association between pesticide exposure and ADHD prevalence [ 75 ]. The study assessed the relationship between DAP exposure during utero and mental development index (MDI) scores at 6 months, 12 months and 24 months of age [ 75 ]. At 24 months, the authors found that high DAP concentrations during pregnancy were associated with significantly lower MDI score. Interestingly, this study also reported a positive association between postnatal DAP concentrations and MDI index, which should be further explored; however, the chances of pervasive developmental disorder (PDD) were also increased by 2-fold for every 10-fold increase in postnatal DAP concentration [ 75 ], suggesting that mental development in children may be impaired in different ways after high prenatal and postnatal exposure to OP metabolites. Other studies [ 36 , 73 ] examining the effects of dietary pesticide exposure have also found similar results, and seemingly agree that following an organic diet protects against elevated pesticide metabolite concentrations in the body.

Considering prenatal exposure to pesticide residues was linked to poorer neurological and cognitive outcomes in children [ 76 ], eating organic may play a neuroprotective role and lead to better developmental outcomes. While other studies have criticized that this claim remains unsubstantiated due to the limitations of measuring past exposures and confounding factors such as differences between growing conditions and lifestyle factors, the benefits of the organic diet seem to be reflected in positive health outcomes of study participants and is a promising avenue of research. However, it is important to also consider the potential consequences of recommending an organic diet to children. For example, the higher associated costs of organic fruits and vegetables may discourage the purchasing and consumption of these nutrient-packed foods, which are essential to proper child nutrition and protective against a variety of diseases, including obesity, cardiovascular diseases and cancers [ 22 ]. Thus, larger prospective cohort studies should be conducted to draw conclusions about the temporal relationship between dietary pesticide exposure from conventional produce and any toxicity-related effects, and these effects must be weighed against the overall impacts of switching to an organic diet in order to establish a direct health benefit to children.

4.6. Risk of Cancers

In a 9.3-year follow-up study [ 77 ], the association of organic consumption frequency and cancer incidence was assessed among 623,080 middle-aged women in the United Kingdom. Although previous studies have shown a lower risk of breast and soft tissue cancer among organic consumers, this prospective study revealed no such relationship. The lack of statistical significance could have been affected by potential confounding factors such as lifestyle choices, genetic predispositions or environmental exposures that were not considered in the study. However, there was some evidence that demonstrated that the risk of NHL was reduced by 21% in women who reported usually or always consuming organic food [ 77 ].

Another study [ 78 ] was designed to assess the overall change in cancer incidence and consumption frequency of organic foods. Following a cohort of 68,946 participants over a mean of 4.6 years, this study revealed that those who consumed organic foods showed a lower risk of NHL (21%, which was similar to the result of a previous study among UK women [ 77 ]) and lower risk of postmenopausal breast cancer among participants who consumed organic food frequently (in contrast with the UK study which found no reduction in breast cancer risk) [ 77 , 78 ]. According to this paper, the negative association between organic food consumption and cancer risk was possibly due to lower exposure to synthetic pesticides in organic farming. Specifically, exposure to certain chemicals, such as malathion, terbufos and diazinon has been associated with a 22% higher risk for NHL [ 78 ]. The same reasoning can be used to explain the reduced risk of breast cancer; lower exposure to synthetic chemicals may lead to a lower risk for breast cancer among frequent organic food consumers [ 78 ].

Exposure to chemical pesticides is also associated with an increased risk of different types of cancers. In the south of Spain, a study [ 79 ] on the population of 10 districts, which were categorized based on the potential environmental exposure to pesticides, showed an increased rate of stomach, colorectal, liver, skin, bladder and brain cancer for regions with a higher level of pesticide exposure. In addition, there was an increased rate of prostate, testicular, and lung cancer among male residents in areas where the level of pesticide exposure was high [ 79 ]. Many experiments were conducted on the potential carcinogenicity of pesticides using animal models, and these studies have confirmed that the potency of the pesticides and the level of exposure should be considered as factors that increase the risk of cancer development [ 80 ]. In animal studies, the carcinogenic potential of some pesticides such as organochlorines, creosote and sulfallate has been observed. Notably, arsenic compounds and insecticides are considered as human carcinogens by the International Agency for Research on Cancer [ 79 ]. Together, these studies suggest that exposure to pesticide chemicals, which are extensively used in conventionally grown products, potentiates cancer risk. Thus, eating more organic foods could help reduce exposure to these pesticides and, consequently, potentially also reduce the risk of dangerous human diseases, although the exact link between disease incidence and reduced pesticide exposure is not well established.

Further on, a 2018 Agricultural Health Study (AHS), which assessed the health outcomes of licensed pesticide applicators in North Carolina and Iowa, evaluated the effect of glyphosate on the development of tumors [ 37 ]. In their study, 82.8% of 54,251 applicators used glyphosate, but there was no statistically significant link between glyphosate and tumor growth [ 37 ]. In spite of this, they found that the highest exposure quartile had an increased risk of acute myeloid leukemia (AML), but this result was not statistically significant [ 37 ]. A 2019 meta-analysis of this AHS data and five new case-control studies reported a 41% increased meta-relative risk of NHL for the highest GBH exposure groups [ 81 ]. However, a recent review of epidemiological studies published in 2020 criticized the weaknesses of this finding, stating that study discrepancies between exposure groups, the lack of direct comparison between each exposure group, and other epidemiological limitations skew the validity of this data [ 82 ]. Thus, the evidence supporting the link between cancer pathogenesis and pesticide exposure is still weak, and further studies are needed to investigate the underlying mechanisms behind these observed associations.

5. Concluding Remarks

Evidence in the current literature suggests that the consumption of organic foods confers promising health advantages for various consumer groups. Multiple statistical analyses have uncovered that organic foods contain significantly higher levels of certain nutrients, including vitamin C, iron and magnesium. Organic food consumption has also shown positive associations with reduced BMI and improved blood nutritional composition across different demographic groups, but these improvements have not been directly linked to specific health outcomes. Further on, organic food has been increasingly popular amongst women due to the claim that they are pesticide-free, and pesticides have been associated with adverse effects on reproductive and immune health.

While some studies suggest links between pesticide exposure and adverse health effects, conflicting results and methodological limitations challenge our ability to conclusively establish the health benefits of reduced pesticide exposure through organic consumption. The limitations in definitively establishing the health benefits of organic foods stem from various factors including study design flaws, selection bias and other confounding variables. Observational studies comparing organic and non-organic consumers often face challenges such as self-reporting issues, small sample sizes and inconsistent data, hindering the definitive conclusions that can be drawn. Thus, rigorous research, incorporating longitudinal studies and considering diverse influencing factors, is imperative to overcome these limitations and provide a more nuanced understanding of the relationship between organic food consumption and health outcomes. While consumers may consider choosing organic options when convenient, it is premature to recommend organic foods for enhanced health without a more comprehensive understanding of the long-term effects of whole-diet substitutions. Further statistical analyses are necessary to ensure that any recommendations align with robust scientific evidence. Moreover, the call for continued research and policy development is crucial in shaping future nutritional guidelines and regulatory considerations. Continued research, thoughtful policy development and a commitment to rigorous methodologies will contribute to a more informed perspective on the role of organic foods in promoting human health.

Acknowledgments

The authors would like to acknowledge team members of AR Environmental Solutions—Esther Somanader and Hiral Patel—for their contribution to the manuscript draft and graphic image Figure 2 , respectively.

Funding Statement

This research received no external funding.

Author Contributions

Conceptualization, A.R.; validation, A.R.; writing—original draft preparation, P.B., D.G.P., E.H.Y.K. and A.R.; writing—review and editing, A.R., P.B., D.G.P., E.H.Y.K., R.R., M.A. and S.P.; statistical analysis, M.A.; visualization, P.B. and A.R.; supervision, A.R.; project administration, A.R.; funding acquisition, A.R. All authors have read and agreed to the published version of the manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

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Organic nanozymes have broad applications from food and agriculture to biomedicine

by Marianne Stein, University of Illinois at Urbana-Champaign

Nanozymes are tiny, engineered substances that mimic the catalytic properties of natural enzymes, and they serve a variety of purposes in biomedicine, chemical engineering, and environmental applications. They are typically made from inorganic materials, including metal-based elements, which makes them unsuitable for many purposes due to their toxicity and high production costs.

Organic-based nanozymes partially overcome some of these problems and have the potential for a broader range of applications, including food and agriculture, but they are still in the early stages of development. A new paper from the University of Illinois Urbana-Champaign provides an overview of the current state of organic nanozymes and their future potential.

The paper , "Advancements in organic materials-based nanozymes for broader applications," is published in Trends in Chemistry .

"Inorganic nanozymes have only been around since 2007, when researchers discovered that iron oxide nanoparticles could perform catalytic activity similar to natural enzymes like peroxidase. Their usage has rapidly advanced, but they have some major drawbacks.

"They are made from expensive ingredients, and they require a time-consuming, heavy engineering process for fabrication. They are potentially toxic to humans and the environment, and they aren't naturally degradable so they cause waste management issues," said lead author Dong Hoon Lee, a doctoral student in the Department of Agricultural and Biological Engineering (ABE), part of the College of Agricultural, Consumer and Environmental Sciences and The Grainger College of Engineering at the U. of I.

These issues led to the emergence of organic nanozymes a few years ago, said Mohammed Kamruzzaman, assistant professor in ABE and co-author of the study.

"Organic nanozymes are cost-effective, non-toxic, and environmentally friendly. The fabrication process is less complicated, and they can be produced in a few hours, compared to several days for inorganic nanozymes," he stated.

"They are also much less expensive. The precious metals that are used for inorganic nanozymes cost around $400 per gram, while the organic materials and transition metal components cost less than 50 cents per gram. This makes them much more accessible for use in real-world applications outside of the laboratory," he added.

Furthermore, organic nanozymes are sustainable, and some of them are biodegradable. They still contain a small metal component, such as iron or copper, which is needed to form an "active site" for the enzyme-like catalytic activity, but at a much lower toxicity level.

In the paper, the researchers identify four main types of organic nanozymes based on the organic materials that are used in creating them, including polymers, biomacromolecules (primarily cellulose), organic compounds, and biological materials such as DNA and peptides. They outline chemical structure, components, functionality, and catalytic activity for each of these types, providing fundamental information for other scientists. They also illustrate the corresponding applications from agriculture, food, and environment to biomedicine.

Inorganic nanozymes originated in the biomedical area, and that's where approximately 80% of research occurs, Kamruzzaman noted. For example, they are used in diagnostic medicine, imaging, therapeutics, and biosensing. However, there are concerns about innate toxicity and their impact on cell viability in therapeutic applications. Organic nanozymes can alleviate those concerns and extend applications to food and agriculture.

In a previous study , Kamruzzaman and Lee pioneered the use of agricultural-centered organic nanozymes and incorporated molecular sensing tools that can detect the presence of agricultural pesticides in food products. The ultimate goal is to create a simple test kit that people can apply anywhere and scan the results with a phone app to get a color reading that indicates the concentration of pesticide in the food. Several additional organic nanozymes made from sustainable materials have also been introduced, and further advanced molecule sensing systems are underway.

"Organic nanozymes have many advantages compared to inorganic nanozymes, but they are still in the early development stages, and there are many challenges that we need to overcome to apply them in the food and agriculture sector," Kamruzzaman said.

One obstacle is a limited range of suitable organic materials for production. The researchers note that lipids or amino acids are promising materials for future prototypes that could play a crucial role in developing the next generation of nanozymes.

Journal information: Trends in Chemistry

Provided by University of Illinois at Urbana-Champaign

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