Samantha Serrano

Project title: Dietary Phthalate Exposure in Pregnant Women

Degree: MS | Program: Environmental Health (EH) | Project type: Thesis/Dissertation
Completed in: 2013 | Faculty advisor: Sheela Sathyanarayana


Background: Phthalates are a family of synthetic chemicals with use in a variety of industrial and consumer products. Due to their bubiquity in the environment, exposures are widespread in the U.S. population. Animal studies have shown that phthalates exhibit anti-androgenic activity and disrupt normal male reproductive tract development during gestation. Similarly, human studies document associations between prenatal phthalate exposure and harmful health outcomes. Food is considered the largest source of the most toxic phthalates for the general population, however, few U.S. studies have investigated diet’s contribution to overall body burden, and none have assessed exposures specifically in pregnant women.

Methods: We used multivariate regression analysis to examine the association between reported dietary intake of various food groups (beef, seafood, poultry, oils, butter, lard, shortening, spices, soy, dairy products, restaurant food/delivery/take-out and fast foods, and drinks in cans and plastic) and first trimester urinary phthalate metabolite concentrations in a multicenter cohort of 283 pregnant women from Minnesota, New York, Washington, and California participating in The Infant Development and Environment Study (TIDES). Additionally, we examined whether reported use of environmentally friendly products and consumption of chemical free diets was associated with urinary phthalate concentrations compared with not following these practices. We adjusted all analyses for maternal age, BMI, race, education, and study center.

Results: Soy intake was found to be associated with increased levels of log mono-n-butyl phthalate (MnBP), a metabolite of di-nbutyl phthalate (DnBP) (β=0.05; 0.01, 0.08). Consumption of dairy was associated with decreased levels of the sum of log di-2-ethylhexyl phthalate (DEHP) metabolites (β = -0.02; -0.03, -0.004). No statistically significant associations were found between beef, seafood, oils, butter, lard, shortening, spices, and restaurant, delivery and fast foods and urinary phthalate metabolites. Additionally, no statistically significant associations were found between environmentally-friendly consumption practices and urinary phthalate metabolite concentrations.

Conclusions: These results suggest that soy products may be a dietary source of di-n-butyl phthalate (DnBP). It is possible that dairy was associated with decreased levels of phthalate metabolites in this study population because we were unable to differentiate between women consuming dairy products containing low concentrations of DEHP phthalates (yogurt, skim milk) versus higher concentrations of DEHP phthalates (cream, cheese, whole milk). This study also suggests that consumption of environmentally-friendly diets may not be protective against phthalate exposures in food.