Many studies of the differences between organic and conventionally farmed foods have focused on nutrient content – with mixed results – but lower pesticide exposure is among the top reasons people buy organic foods.
This study, published in Environmental Health Perspectives, confirms that consumers of organic foods may indeed have much lower exposure to pesticides – but non-organic consumers are still 500 times below established risk levels.
The University of Washington researchers surveyed more than 4,400 consumers about their eating habits and combined the data with information on pesticide use to estimate their exposure to organophosphate pesticides (OP).
OP exposure has been linked to adverse health effects among farmworkers, but this is thought to be the largest study of its kind, looking at pesticide exposure from diet among the general population.
“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,” said the paper’s lead researcher Dr Cynthia Curl.
It is still unknown whether dietary pesticide exposure has any effect on health, and this is where Curl next intends to direct her research.
“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 4,500 people,” she said.
Less invasive research
“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,” she added. “That will allow research on organic food to be both less expensive and less invasive.”
Although the study found much lower exposure from organic foods, head of Pharmacology at the University of Adelaide, Dr Ian Musgrave, said the health risk from conventional produce versus organic produce was negligible.
“If you look at how much these people are being exposed to, it’s about 1000-fold less than the estimated safety levels of pesticide exposure,” he told the Sydney Morning Herald.
"If you eat mostly or only organic produce, you will excrete fewer pesticide metabolites but the risk of having more pesticide metabolites in your body compared to the benefits of eating more fruit and vegetables is negligible."
Source: Environmental Health Perspectives
Published online ahead of print http://dx.doi.org/10.1289/ehp.1408197
“Estimating Pesticide Exposure from Dietary Intake and Organic Food Choices: The Multi-Ethnic Study of Atherosclerosis (MESA)”
Authors: Cynthia L. Curl, Shirley A.A. Beresford, Richard A. Fenske, Annette L. Fitzpatrick, Chensheng Lu, Jennifer A. Nettleton, and Joel D. Kaufman