Racial/ethnic differences in prenatal dietary intake of antioxidants and methyl-donors: Implications for environmental health risk

Abstract

Background: Oxidative stress and epigenetic changes are key mechanisms for environmental exposures, including ambient air pollution. Antioxidants and methyl-donors may modulate toxic effects. Aim: We examined correlates of total dietary intakes of antioxidants and methyl-donors in an urban, ethnically mixed prenatal cohort (n=275) designed to study the effects of traffic-related air pollution, social stress, and dietary factors on prenatal programming of autonomic function. Methods: Total daily antioxidant and methyl-donor intakes were calculated from a food frequency questionnaire. Estimated Average Requirements indexed antioxidant/methyl-donor inadequacy (?2 micronutrient inadequacies per group). Stress was indexed by negative life events. We examined differences in dietary intakes based on race and stress levels. Race-stratified logistic regression was used to examine effects of social stress on antioxidant and methyl-donor inadequacy adjusting for maternal education and body mass index. Results: Women were largely minority (43% Hispanic, 18% black, and 8% mixed). Vitamins E, folate, B6, and trace minerals zinc, magnesium, and iron were the most prevalent inadequacies. Differing antioxidant and methyl-donor intakes were observed by race, with blacks and Hispanics consistently having lower intakes than their counterparts (p<0.01). Higher stress was associated with antioxidant and methyl-donor inadequacy, particularly among blacks [odds of antioxidant (aOR: 2.09, 95% CI 1.15-3.80) and methyl-donor (aOR: 2.22, 95% CI 1.16-4.25) inadequacy]. Conclusions: Observed racial differences in dietary intakes of antioxidants/methyl-donors may, in part, explain differences in vulnerability to environmental toxicants (e.g., traffic pollution) and consequent health disparities. Next steps will include assessing modifying effects of dietary inadequacies on the role of traffic pollution-related fetal programming across racial groups.