Identifying Foods That Optimize Intake of Key Micronutrients During Pregnancy

Abstract

Background: Most pregnant women in the United States are at risk of inadequate intake of vitamin A, vitamin D, folic acid, calcium, iron, and omega-3 fatty acids from foods alone. Very few United States dietary supplements provide sufficient doses of all 6 nutrients without inducing excess intake.

Objective: We aimed to identify energy-efficient foods that provide sufficient doses of these nutrients and could be consumed in lieu of dietary supplements to achieve the recommended intake in pregnancy.

Methods: In a previous analysis of 2,450 pregnant women, we calculated the range of additional intake needed to shift 90% of participants to intake above the estimated average requirement and keep 90% below the tolerable upper level for these 6 nutrients. Here, we identified foods and beverages from the 2019 to 2020 Food and Nutrient Database for Dietary Studies that provide target levels of these nutrients without exceeding the additional energy intake recommended for pregnancy beginning in the second trimester (340 kilocalories).

Results: We identified 2358 candidate foods meeting the target intake range for at least one nutrient. No candidate foods provided target amounts of all 6 nutrients. Seaweed (raw or cooked without fat) provided sufficient vitamin A, folate, calcium, iron, and omega-3s (5 of 6 nutrients) but would require an intake of >5 cups/d. Twenty-one other foods/beverages (mainly fish, vegetables, and beverages) provided target amounts of 4 of the 6 nutrients. Few foods met targets for vitamin D (n = 54) or iron (n = 93).

Conclusions: Results highlight the difficulty in meeting nutritional requirements from diet alone and imply that dietary supplements are likely necessary to meet vitamin D and iron targets in pregnancy, as well as omega-3 fatty acid targets for individuals who do not consume fish products. Other foods could be added in limited amounts to help meet intake targets without exceeding caloric recommendations or nutrient safety limits.

Keywords: calcium; dietary reference intakes; folic acid; food intake; iron; omega-3 fatty acids; pregnancy; vitamin A; vitamin D.