Even kids who eat only organic can’t always escape exposure to pesticides

A study published in the journal Environmental Health Perspectives found that an organic-only diet led to a drop in exposure to pesticides common in food production, but kids were still exposed to pesticides from other sources. Previous studies have shown that organic diet interventions can lead to quick drops in the presence of certain pesticides in children’s urine, but those studies focused on dietary exposure instead of overall exposure. Researchers from the University of California, Berkeley, wanted to get a bigger picture of pesticide exposure and so focused on populations unrepresented in the previous studies. Specifically, those studies did not look at low-income children in either agricultural or urban communities, but instead focused on suburban and non-agricultural residents.

To close that gap, researchers tested two sample groups of children—20 kids from Oakland, California (an urban area) and 20 more from Salinas, California (an agricultural one). All were aged 3 to 6 years old, from low-income communities, and to keep cultural disparities from playing a role, either Mexican American or Mexican immigrants. In the Salinas group, at least one member of the household was an agricultural worker. The children ate conventional foods for four days, organic for seven and then conventional again for five. Beyond organic vs. non-organic, diets stayed relatively constant and urine samples were collected daily.

When the scientists tested the children’s urine for metabolites—molecules formed during metabolism—representing different pesticides, they found that while the organic diet resulted in a drop in some of those substances, it did not cause a significant drop in others. Unsurprisingly, the drops were significant for the metabolites resulting from pesticides used in food production, like organophosphate insecticides and the 2,4-D herbicide, but not for those typically used around the house (e.g. in bug spray) or detected in drinking water. Levels of certain metabolites were also higher in the Salinas children than the Oakland children, which the authors note is consistent with the kids’ environments: The Salinas children live in an area where the pesticides are used; the Oakland children do not.

“That could mean that the diet wasn’t an important source of exposure for those pesticides,” lead researcher Asa Bradman told Civil Eats. The results point to the need to consider pesticide exposure from the environment at large, he said, not just through diet. “When considering risk from exposure, I wouldn’t say that conventional foods are unsafe,” he said. “If you look at the American diet, there’s definitely great need for more fruits and vegetables and less refined carbohydrates.” If a parent’s ultimate goal is to protect his/her children from pesticides, focusing on diet is too narrow of an approach.

This is not the first time researchers have questioned the need to worry about pesticide exposure from conventional foods. In 2011, University of California scientists reported that even the so-called “dirtiest” fruits and vegetables had less than 2% of the maximum amount of pesticides allowed by the US Environmental Protection Agency. They found there was “no appreciable reduction of consumer risks” in choosing the organic versions.

While the study has some inherent limits—a small, racially homogenous sample, for example—it might be helpful to keep it in mind next time you’re at the grocery store, looking at organic produce that can be more than three times the price of its conventional counterparts. Pesticide exposure can be dangerous, but trying to limit it through a strictly organic diet might be an expensive—and ineffective—way to do it.