Effect of a Longitudinal, Randomized Organic Diet Intervention on 2,4-D, Pyrethroid and Organophosphate Pesticide Exposures among Pregnant Women

Abstract

Background: Several short-term (1-2 week) interventions in children and adults have shown that introduction of a fully “organic” diet can significantly reduce pesticide exposure.Objectives: We assessed the effect of a long-term (6 month) organic diet intervention on pesticide exposure among pregnant women. We supplemented women’s existing diets with weekly deliveries of either organic or conventional produce to reflect real-world consumption patterns. We hypothesized that pesticide exposure would be lower in the organic group.Methods: We recruited 20 women in their first trimesters of pregnancy. Eligible women were non-smokers aged 18-35 who reported eating exclusively conventionally-grown food. Participants were randomized to receive weekly deliveries of either organic or conventional produce throughout their second and third trimesters. They completed daily food diaries and provided weekly spot urine samples. Urine samples were pooled to represent monthly exposures and analyzed for eight biomarkers representing exposure to one herbicide, seven organophosphates and eight pyrethroid insecticides.Results: We collected an average of 23 weekly samples per participant, for a total of 461 individual samples. We detected p-nitrophenol (PNP), 2,4-dichlorophenoxyacetic acid (2,4-D,) and 3-phenoxybenzoic acid (3-PBA) in 99%, 90%, and 74% of samples, respectively. Long-term average concentrations of 2,4-D and 3-PBA were significantly lower in women in the organic group compared to the conventional group (2,4-D: 0.36 vs 0.57 μg/L, p=0.05; 3-PBA: 0.70 vs 2.21 μg/L, p=0.02). PNP concentrations were also lower in the organic group, but this difference was not significant (0.54 vs 0.63 μg/L, p = 0.3).Conclusion: This is the first long-term organic diet intervention study and the first to evaluate pregnant women. Concentrations of 2,4-D and 3-PBA were significantly reduced in women whose diets were supplemented with organic produce compared to those receiving conventional produce.