Supplement use in relation to dietary intake in pregnancy - an analysis of the Swedish GraviD cohort.

We aimed to study supplement use in relation to dietary intake among pregnant women in Sweden, and adherence to the Nordic Nutrition Recommendations among supplement and non-supplement users. Pregnant women were recruited at registration to antenatal care in 2013-2014. In third trimester, supplement use was collected using a questionnaire, and dietary intake was collected using a food frequency questionnaire. The majority (64%) of the 1044 women reported use of one or more supplements. Among all, 0-23% reported dietary intakes above recommended intake (RI) of vitamin D, folate, iron, and selenium. Median dietary intakes of thiamine (1.4 vs 1.3 mg p=0.013), phosphorus (1482 vs 1440 mg p=0.007), folate (327 vs 316 µg p=0.02), iron (12 vs 11.5 mg p=0.009), magnesium (361 vs 346 mg p<0.001), and zinc (10.7 vs 10.4 mg p=0.01) were higher among supplement users compared to non-users. Larger proportions of supplement users than non-users adhered to RI of dietary intakes of thiamine (42% vs 35% p=0.04) and magnesium (75% vs 69% p=0.05). Among non-users, a minority had dietary intakes above RI for vitamin D (6%), folate (10%), and iron (21%). The majority (75-100%) of supplement users had total intakes above RI for most nutrients. In conclusion, supplement use contributed substantially to reaching RI for vitamin D, folate, and iron. Supplement users had a higher dietary intake of several nutrients than non-users. This highlights that non-supplement users are at risk of inadequate nutrient intakes during pregnancy, suggesting a need for heightened awareness of nutritional adequacy for pregnant women.