Adequacy of nutritional intake from food and supplements in a cohort of pregnant women in Québec, Canada: the 3D Cohort Study (Design, Develop, Discover)

Background: Assessments of the dietary intakes in various populations suggest that pregnant women have difficulty meeting all their nutritional requirements through diet alone. Few large-scale studies have considered both food sources and supplements in assessing the adequacy of nutritional intakes during pregnancy.Objective: Our study aimed to assess nutritional intakes during pregnancy by examining dietary sources and supplements. It then compared these findings with Dietary Reference Intakes.Design: We conducted a nutrition study in a large pregnancy cohort using a 3-d food record during the second trimester of pregnancy. Detailed information about supplement consumption was obtained by interview at each prenatal visit. We estimated the distribution of total usual intakes for energy, macronutrients, and micronutrients for 1533 pregnant women.Results: A third of the participants had total fat intakes that exceeded the Acceptable Micronutrient Distribution Range. A majority of women (85%) had sodium intakes above the Tolerable Upper Intake Level (UL). Median intakes for fiber and potassium were lower than Adequate Intakes. Dietary intakes of vitamin B-6, magnesium, and zinc were below the Estimated Average Requirements (EARs) for 10-15% of the women. A majority of the women had dietary intakes below the EARs for iron (97%), vitamin D (96%), and folate (70%). When we considered micronutrient intakes from both food and supplements, we found that the prevalence of inadequate intake was <10% for all nutrients except vitamin D (18%) and iron (15%), whereas 32% and 87% of the women had total intakes above the ULs for iron and folic acid, respectively.Conclusions: The level of intake of some nutrients from food alone remains low in the diets of pregnant women. Supplement use reduces the risk of inadequate intake for many micronutrients, but diet-related issues during pregnancy remain and deserve to be addressed in public health interventions. This trial was registered at clinicaltrials.gov as NCT03113331.