Too often we hear the maxim of eating plenty of fruits and vegetables for optimal health. At face value, it seems obvious that something coming out of the earth with vibrant colors and minimal processing should contribute positively to our longevity. It may surprise you to hear that some of the most common fruits and vegetables to hit our plates contain neurotoxins, carcinogens, and endocrine (hormone) disrupting compounds (EDCs). [1-4,9]
The dirty dozen
The Environmental Working Group (EWG) and USDA evaluate testing data on non-organic and organically grown produce in the United States with the aim of creating a list of the most pesticide-laden fruits and vegetables. Every year, this produce is ranked on a spectrum that becomes “the dirty dozen” and “the clean fifteen”. As you may guess, the dirty dozen has the most pesticide residue and the clean fifteen has the least. 
Before reading these studies, if I were to guess how often pesticides remain on produce even after washing I likely would’ve thrown out a single-digit percentage of all fruits and vegetables. In reality, about 70% of all non-organic fresh produce has residues of chemical pesticides. 
Some important findings about non-organic produce :
- Over 90% of cherries, spinach, nectarines, apples, strawberries, and leafy greens were found to have two or more pesticide residues even after washing, scrubbing, and/or peeling
- One sample of leafy greens contained as many as 20 unique pesticides
- Spicy and bell peppers had 115 pesticide residues
- Spinach had 80% more pesticide residue by weight than any other crop tested
The 2021 dirty dozen, as listed by EWG, includes the following non-organic fruits and vegetables :
- Kale and leafy greens
- Bell and hot peppers
But what’s the issue with a little pesticide or fungicide left on food?
Many of these chemical residues have been linked to widespread problematic side effects. One chemical fungicide, Imazalil, was found in over 95% of tangerine samples and almost 90% of all citrus samples. Imazalil is a listed possible human carcinogen (cancer causing molecule) and likely endocrine disruptor, potentially affecting fertility and more. [1-4]
Similarly concerning are the chemical compounds found on leafy greens, most commonly of which is the pesticide DCPA. Here is a direct quote from the Environmental Protection Agency (EPA) regarding DCPA:
DCPA has been classified as a Group C, possible carcinogen, based on increased incidence of thyroid tumors in both sexes of the rat (although only at an excessive dose in the female), and liver tumors in female rats and mice, at doses which were not excessive. 
Let us take this disturbingly apathetic policy further. The EPA has approved the use of DCPA to “control annual grasses and broadleaf weeds on ornamental turf and plants, strawberries, seeded and transplanted vegetables, cotton, and field beans” that go on to be consumed by humans.
Interestingly, the EPA prohibits feeding clippings, treated foliage, or treated hay to any livestock. Further, DCPA is banned in nearly any capacity for use in, near, or around lakes, ponds, streams, estuaries, and larger bodies of water. 
One wonders how a product that can’t be fed to the animals we eat, instead, can be fed directly to us. If the carcinogenic capacity of DCPA does not worry you, consider that it is listed as slightly toxic for the skin, eyes, and lungs as well. 
Acephates and other organophosphate pesticides are especially concerning for their effects on fertility and development. While acephates are banned in the European Union, their use remains permitted in the U.S. even with documented incidents of reduced luteinizing hormone and inhibited brain acetylcholinesterase activity. The former possibly affects reproductive function and the latter has been connected to several brain disorders and neurodegenerative disorders. [1,8]
Finally, to add to the list of concerning findings, the USDA does not collect data on all known chemical pesticides used in the U.S. Particularly curious is that they do not test for pesticide residues from the most commonly used pesticide in the world: Roundup (glyphosate). [6,7]
While glyphosate is suggested to be safe for human contact, it has been shown to negatively impact beneficial bacteria and boost harmful bacteria in your gut microbiome. [6,7]
How do you avoid these pesticide residues?
At a basic level, avoid non-organic industrially grown fruits and vegetables as much as possible. To reiterate, the samples were analyzed after washing, straining, and at times, peeling. That means the positive tests for pesticide residues were occasionally in the food itself.
Source your produce and meat from organic farms as much as possible. Organically grown fruits, vegetables, and grains are prohibited from using these same chemical pesticides.
Sometimes, you may live near someone who goes "beyond organic" with food production. In other words, that means they don't spray any compound on their crops ever. We recently wrote an article about micronutrient density in these cases as well. Spoiler alert, the greens you buy at super markets have about half of the critical nutrients you'd find from freshly harvested greens at your local market.
If a choice is between no vegetables or non-organic vegetables, there are still some options that the EWG and USDA consider the clean fifteen. While they are the fifteen cleanest fruits and vegetables, that does not mean they were completely devoid of pesticides when sampled. Organic options still prevail over these 2021 clean fifteen:
- Sweet corn
- Sweet peas (frozen)
- Honeydew melon
Of these fifteen, nearly 70% had no residues, but 8% of all samples still had two or more pesticides remaining after cleaning. 
The best case? Choose beyond organic and local. You get more nutrients and you know where your food comes from.
If you're like us, the cleanest option may not always be there. We'll still get that carrot or swiss chard, but those greens will definitely get more scrubbing than before.
- EWG Science Team. EWG’s 2021 Shopper’s Guide to Pesticides in Produce. Environmental Working Group. March 17, 2021.
- Pesticide Action Network Europe. Endocrine Disrupting Pesticides in European Food. 2017.
- Hurley PM. Mode of carcinogenic action of pesticides inducing thyroid follicular cell tumors in rodents. Environ Health Perspect. 1998;106(8):437-445. doi:10.1289/ehp.98106437
- Kojima H, Katsura E, Takeuchi S, Niiyama K, Kobayashi K. Screening for estrogen and androgen receptor activities in 200 pesticides by in vitro reporter gene assays using Chinese hamster ovary cells. Environ Health Perspect. 2004;112(5):524-531. doi:10.1289/ehp.6649
- Environmental Protection Agency (EPA). R.E.D Facts for DCPA. Prevention, Pesticides And Toxic Substances. November 1998.
- Kim YH, Hong JR, Gil HW, Song HY, Hong SY. Mixtures of glyphosate and surfactant TN20 accelerate cell death via mitochondrial damage-induced apoptosis and necrosis. Toxicol In Vitro. 2013 Feb;27(1):191-7. doi: 10.1016/j.tiv.2012.09.021. Epub 2012 Oct 23. PMID: 23099315.
- Coleman, Pamela. Gut-Wrenching: New Studies Reveal the Insidious Effects of Glyphosate. The Cornucopia Institute. 2014.
- Rattner et al. Organophosphorus insecticide induced decrease in plasma luteinizing hormone concentration in white-footed mice. Toxicology Letters. 1985.
- Chiu Y, Williams PL, Gillman MW, et al. Association Between Pesticide Residue Intake From Consumption of Fruits and Vegetables and Pregnancy Outcomes Among Women Undergoing Infertility Treatment With Assisted Reproductive Technology. JAMA Intern Med. 2018;178(1):17–26. doi:10.1001/jamainternmed.2017.5038