Effect of a Randomized, Blinded Organic Diet Intervention on Pesticide Exposure among Pregnant Women

摘要

Background: Food is certified "organic" when grown according to specific requirements, including the absence of most synthetic pesticides. The organic food market is among the fastest growing sectors of the agricultural industry, primarily due to a perception that organically-grown food is "healthier" than food that is conventionally-grown. However, there is almost no data to support (or refute) this perception. Most researchers do agree that an organic diet can reduce exposure to agricultural pesticides. It is also known that maternal exposure to some classes of pesticides during pregnancy is associated with subsequent decrements in cognitive, behavioral, and neurological outcomes in children. However, it is not known whether the amount of pesticide exposure resulting from a conventional diet is substantial enough to cause these decrements, and whether any such effects could be prevented with an organic diet. Objectives: The purpose of this pilot project was to develop methodology for a future study of the effect of a maternal organic diet during pregnancy on subsequent cognitive outcomes in children. We aimed to: 1) design an effective recruitment strategy and a means to deliver organic and conventional produce to study participants in a blinded and scalable fashion, and 2) assess compliance with and efficacy of the dietary intervention through repeated measurement of urinary metabolites. Methods: We partnered with Women, Infants, and Children (WIC) clinics in Idaho's Treasure Valley to recruit 20 women during their first trimester of pregnancy. Eligible women were 18-35 years of age, non-smoking, and were not expected to have a high-risk pregnancy. All participants reported eating exclusively conventionally-grown food at the time of recruitment. An equal number of participants were randomized to the organic and conventional groups; based on group assignment, each woman received weekly deliveries of either organic or conventional produce throughout their second and third trimesters. Participants also provided weekly urine samples and completed food diaries using a mobile phone app or written diaries. Results: Weekly urine samples are pooled to represent monthly exposures throughout the second and third trimester of pregnancy. Pooled samples are analyzed for metabolites representing exposure to one herbicide (2,4-dicholorphenoxyacetic acid), seven organophosphate insecticides (diazinon, parathion, methyl parathion, ethyl parathion, chlorypyrifos, chlorpyrifos-methyl, and malathion), and eight pyrethriod insecticides (cyfluthrin, cyhalothrin, cypermethrin, deltamethrin, fenpropathrin, flumethrin, permethrin and tralomethrin). We will compare pesticide exposures across the organic and conventional groups and will investigate individual produce items associated with the highest concentrations of urinary pesticide metabolites.