On Nutrition

A little while ago, a reader asked me, “Why is nonorganic produce for sale if it’s supposedly not safe to eat? Seeing two of everything at the grocery store angers and confuses me.” The idea that “nonorganic” produce, typically referred to as “conventional” produce, is unsafe to eat is pervasive, and it largely hinges on a narrow definition of “safe” (i.e., pesticide-free) as well as a black-and-white view of what goes into the production of organic and conventional crops.

According to consumer research, shoppers who reach for organic produce want to avoid a lot of things in or on food, including pesticides and other chemicals. The thought is that not only are organic foods are safer, but they’re more nutritious and healthful. I’ve had new patients and clients blurt out “I only eat organic food” within moments of meeting me, as if organic is the singular defining quality of health.

What do we mean when we say “pesticide-free”?

Contrary to what most people believe, “organic” does not necessarily mean “pesticide-free.” Just as both organic and conventional farms come in all sizes — from family farms to large “factory farms” — organic and conventional farms can use pesticides to protect crops from pests, weeds and disease. What’s different is which pesticides they’re allowed to use.

Food certified “organic” under the U.S. Department of Agriculture (USDA) National Organic Program (NOP) can only be produced using specific pesticides allowed by the NOP. Generally, natural substances are allowed unless specifically prohibited — arsenic and strychnine are two no-nos — and synthetic (human-made) substances are prohibited unless specifically allowed because there’s no organic substitute and the substance is deemed safe.

What do we mean when we say “safe”?

Many substances are safe unless they are used excessively. Alcohol is a toxin, but it’s not a problem for most people if consumed in moderation. Acetaminophen, the active ingredient in Tylenol, can cause liver damage if you exceed the recommended dose.

“The first principle of toxicology is ‘the dose makes the poison,’” said Carl Winter, who was a food toxicologist at University of California Cooperative Extension for 32 years before retiring last year. “It is the amount of exposure to a chemical, not its presence or absence, that determines the potential for harm. In the case of pesticide residues, the levels are typically far lower than those required to produce harm.” 


Last month, the U.S. Food and Drug Administration (FDA) issued its annual Pesticide Residue Monitoring Program Report for 2018. The program ensures that FDA-regulated foods sold in this country comply with the maximum residue levels set by the Environmental Protection Agency (EPA). The FDA tested 4,404 human food samples for 809 pesticides and industrial chemicals. Of the 1,448 samples produced or grown in the U.S., 96.8% were in compliance and 47.1% had no detectable residues. Of the 2,956 imported food samples, 87.1% were in compliance and 47.2% had no detectable residues. 

“While pesticide residues tend to be a little higher in conventional fruits and vegetables than in their organic counterparts, the levels of exposure to pesticides from consuming conventional produce are far lower than those required for health concern,” Winter said.

Wait … a little higher in conventional fruits and vegetables? Yes, due to contamination, most organic produce has detectable levels of not-approved-for-organic pesticides. As long as the residue levels are below 5% of the tolerance level set by the EPA, they are considered “unintentional,” and the produce can still be sold as organic. Fun fact: For the crops included on the Environmental Working Group’s annual “Dirty Dozen” list, the majority of pesticide residues on both the conventional and organic versions are low enough to be allowed under organic rules.

“If consumers were exposed to 100,000 times more pesticide residue than they are typically exposed to on a daily basis throughout their lifetimes,” Winter said, “their levels of exposure would still be lower than levels that don’t even produce any noticeable toxicological effect in long-term animal toxicology studies.”

What do we mean when we say “organic” and “conventional”?

In some cases, parsing the difference between “organic” and “conventional” is like splitting hairs. For example, I’ve toured farms that grow both organic and conventional versions of the same crops, using nearly identical methods. I’ve known farmers who don’t have the resources to seek organic certification, even though they are organic in practice. Some conventional farmers avoid using pesticides but use a once-yearly application of an herbicide to keep down weeds. Other farmers are transitioning from conventional to organic — or vice versa. One size does not fit all.

“There is no evidence that organic foods are healthier than conventional foods and some evidence, in fact, that organic foods could provide greater risks from microbiological contamination [i.e., bacteria and viruses] and naturally-occurring toxins,” Winter said. 

Under the “spirit” of organic agriculture, approved pesticides are a last resort to help control the pests and disease that can damage or destroy crops — after using tools and techniques like insect traps, careful crop selection, crop rotation, beneficial organisms and adjustments to planting and harvesting date. But many conventional farmers use these techniques, too. It’s a myth that they’re spraying synthetic pesticides with abandon, if for no other reason than pesticides are both expensive and tightly regulated. Plus, many farmers live on their farms — why would they want to use more than they need to prevent pests or disease from wiping out their livelihood?

“My biggest concern is that consumers who are worried about pesticide residues in conventional fruits and vegetables and who are urged to purchase organic foods whenever possible might ultimately reduce the amounts of fruits and vegetables they feed themselves and their family members,” Winter said. “In essence, they may be doing themselves more harm than good, since a diet rich in consumption of fruits, vegetables and whole grains has been shown to significantly decrease one’s risk of cancer and heart disease.”