Researchers predict pesticide exposure in humans

Research into the costs and benefits of organic foods is set to become less expensive and invasive, thanks to a new study which is among the first to predict a person’s pesticide exposure based on information about their usual diet.

The study, which has been published in Environmental Health Perspectives, analysed the dietary exposure of nearly 4500 people from six US cities to organophosphates (OPs), the most common insecticides used on conventionally grown produce in the United States.

Results showed that among individuals eating similar amounts of fruits and vegetables, those who reported eating organic produce had significantly lower OP pesticide exposures than those consuming conventionally grown produce. In addition, consuming those conventionally grown foods typically treated with more of these pesticides during production, including apples, nectarines and peaches, was associated with significantly higher levels of exposure.

“For most Americans, diet is the primary source of OP pesticide exposure,” said Cynthia Curl, assistant professor in Boise State University’s School of Allied Health Sciences and the lead researcher of the study. “The study suggests that by eating organically grown versions of those foods highest in pesticide residues, we can make a measurable difference in the levels of pesticides in our bodies.”

The study included dietary data collected from participants in the Multi-Ethnic Study of Atherosclerosis, a large, multi-institutional project that is investigating factors that influence the onset of cardiovascular disease.

The researchers were able to predict each participant’s exposure to OP pesticides based on the amount and type of produce each participant typically ate and the US Department of Agriculture’s measurements of pesticide residue levels on those foods. The researchers then compared these predictions to pesticide metabolite levels measured in urine samples from a subset of 720 of these people.

The method used in this study may have significant implications for future research. By combining self-reported information on typical food consumption with USDA measurements, researchers will be able to conduct research on the relationship between dietary pesticide exposure and health outcomes in bigger populations, without needing to measure urinary metabolites.

“If we can predict pesticide exposure using dietary questionnaire data, then we may be able to understand the potential health effects of dietary exposure to pesticides without having to collect biological samples from people,” Curl said. “That will allow research on organic food to be both less expensive and less invasive.

“The next step is to use these exposure predictions to examine the relationship between dietary exposure to pesticides and health outcomes, including neurological and cognitive endpoints. We’ll be able to do that in this same population of nearly 4500 people,” she said.

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