Journal
JOURNAL OF NUTRITION
Volume 146, Issue 8, Pages 1537-1545Publisher
OXFORD UNIV PRESS
DOI: 10.3945/jn.116.229971
Keywords
pregnancy; lactation; vitamin D; 25-hydroxyvitamin D; 1,25-dihydroxyvitamin D; 24,25-dihydroxyvitamin D; 25(OH)D:24,25(OH)(2)D ratio; free 25( OH)D; Epi-25(OH)D-3; vitamin D requirements
Categories
Funding
- Gerber Foundation [1843-3882]
- NIH [1R03HD080824-01A1]
- USDA National Institute of Food and Agriculture, Agriculture and Food Research Initiative Education and Literacy Initiative Predoctoral Fellowship [2016-67011-25174]
- American Egg Board/Egg Nutrition Center
- Beef Checkoff through the National Cattlemen's Beef Association and Nebraska Beef Council
Ask authors/readers for more resources
Background: The impact of the reproductive state on vitamin D metabolism and requirements is uncertain in part because of a lack of studies with controlled dietary intakes of vitamin D and related nutrients. Objective: We aimed to quantify the impact of the reproductive state on a panel of vitamin D biomarkers among women of childbearing age consuming equivalent amounts of vitamin D and related nutrients. Methods: Nested within a feeding study providing 2 doses of choline, healthy pregnant (26-29 wk gestation; n = 26), lactating (5 wk postpartum; n = 28), and control (nonpregnant/nonlactating; n = 21) women consumed a single amount of vitamin D (511 +/- 48 IU/d: 311 +/- 48 IU/d from diet and 200 IU/d as supplemental cholecalciferol) and related nutrients (1.6 +/- 0.4 g Ca/d and 1.9 +/- 0.3 g P/d) for 10 wk. Vitamin D biomarkers were measured in blood obtained at baseline and study end, and differences in biomarker response among the reproductive groups were assessed with linear mixed models adjusted for influential covariates (e.g., body mass index, season, race/ethnicity). Results: At study end, pregnant women had higher (P < 0.01) circulating concentrations of 25-hydroxyvitamin D [25(OH)D; 30%], 1,25-dihydroxyvitamin D [1,25(OH)(2)D; 80%], vitamin D binding protein (67%), and C3 epimer of 25(OH)D-3 (100%) than control women. Pregnant women also had higher (P <= 0.04) ratios of 25(OH)D to 24,25-dihydroxyvitamin D [24,25(OH)(2)D; 40%] and 1,25(OH)(2)D to 25(OH)D (50%) than control women. In contrast, no differences (P >= 0.15) in vitamin D biomarkers were detected between the lactating and control groups. Notably, the study vitamin D dose of 511 IU/d achieved vitamin D adequacy in most participants (95%) regardless of their reproductive state. Conclusions: The higher concentrations of vitamin D biomarkers among pregnant women than among control women suggest that metabolic adaptations, likely involving the placenta, transpire to enhance vitamin D supply during pregnancy. The study findings also support the adequacy of the current vitamin D RDA of 600 IU for achieving serum 5(OH)D concentrations >= 50 nmol/L among women differing in their reproductive state. This trial was registered at clinicaltrials.gov as NCT01127022.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available