Reducing Prenatal Phthalate Exposure Through Maternal Dietary Changes: Results from a Pilot Study

Diet is a major source of exposure to certain phthalates, a class of environmental chemicals associated with endocrine disruption in animal models and humans. Several studies have attempted to lower phthalate exposure through carefully designed dietary interventions, with inconsistent results. We conducted a dietary intervention pilot study with the objective to lower phthalate exposure in low-income pregnant women, a particularly vulnerable population. Ten pregnant women consumed a provided diet consisting of mostly fresh, organic foods for 3 days. We collected urine samples before, during, and after the intervention and conducted semi-structured interviews to assess the feasibility and acceptability of the intervention. We used repeated measures ANOVA and paired t-tests to assess differences in urinary phthalate metabolite concentrations across the study, focusing on the metabolites of di-2-ethylhexyl phthalate (DEHP), a phthalate of particular interest, and their molar sum (aDEHP). Phthalate metabolite concentrations did not change appreciably during the intervention period. We observed no significant difference in aDEHP metabolite concentrations across the three time periods (F = 0.21; adjusted p value = 0.65), and no reduction during the intervention as compared to baseline (t = -1.07, adjusted p value = 0.51). Results of interviews indicated that participants were not motivated to make dietary changes to potentially reduce chemical exposures outside of the study. Despite the small sample size, our results suggest that promoting dietary changes to lower phthalate exposure may not be an effective public health measure. Reducing the use of phthalates in food processing and packaging may be a better solution to lowering exposure on a population level.