Micronutrient intake from food and supplements in pregnancy: The Healthy Start Study

Abstract

Prenatal multivitamin/multimineral supplementation is commonly recommended to optimize maternal‐child health outcomes. However, in the presence of food fortification and access to nutrient‐adequate diets, supplementation may result in pregnant women consuming micronutrients in excess of the recommended amounts. This could potentially result in adverse offspring outcomes through alterations in DNA methylation due to excess consumption of methyl donors. The purpose of this analysis was to compare micronutrient intake from foods and supplements to the dietary reference intakes (DRIs) of selected micronutrients in pregnancy. We collected longitudinal data from 1322 ethnically‐diverse women participating in The Healthy Start Study, a pre‐birth prospective cohort based in Denver, CO. Women completed research visits in early pregnancy (median 17 weeks gestation), mid‐pregnancy (median 27 weeks), and at delivery (median 1 day post‐delivery). Women self‐reported dietary supplement use at each research visit, including brand/type of vitamin, dosage, and dates of use. Food intake was assessed with automated self‐administered 24‐hour recalls up to 8 times in pregnancy (median 2 recalls). Micronutrient intake from dietary supplements was estimated using manufacturer nutrient composition data. Micronutrient intake from food sources was estimated using the Food and Nutrient Database for Dietary Studies and the National Cancer Institute measurement error model. We calculated average daily intake during pregnancy for the following micronutrients: folate/folic acid, calcium, vitamin D, iron, vitamin B1, vitamin B2, vitamin B3, vitamin B6, vitamin C, vitamin E, and choline. We compared average daily intake from food, supplements, and both sources to the age‐specific DRIs for pregnant women. From food sources alone, women met or exceeded the DRIs for calcium (median 110% of the DRI), vitamin B3 (123%), and vitamin C (146%), but consumed less than the DRIs for vitamin D (30%), vitamin E (45%), vitamin B1 (50%), vitamin B6 (57%), iron (57%), choline (69%), folate (77%), and vitamin B2 (90%). Considering both food and supplement sources, women met or exceeded the DRI for all micronutrients except choline (70%), vitamin D (80%), and vitamin E (97%). Total intake exceeded the DRI by more than 50% for folate/folic acid (158%), vitamin B6 (159%), vitamin B2 (168%), vitamin B3 (182%), and vitamin C (212%). Our data demonstrate that pregnant women are meeting few of the micronutrient DRIs from food sources alone, but are exceeding several of the micronutrient DRIs by 50% or more from combined food and supplement sources. Future research should examine whether and how micronutrient intake in pregnancy, particularly when in excess of the DRIs, is related to offspring health outcomes.Support or Funding InformationNational Institutes of Health