Both Mother and Infant Require a Vitamin D Supplement to Ensure That Infants' Vitamin D Status Meets Current Guidelines.

We examined the association between maternal vitamin D intake during breastfeeding with their infants' vitamin D status in infants who did or did not receive vitamin D supplements to determine whether infant supplementation was sufficient. Using plasma from a subset of breastfed infants in the APrON (Alberta Pregnant Outcomes and Nutrition) cohort, vitamin D status was measured by liquid chromatography-tandem mass spectrometry. Maternal and infants' dietary data were obtained from APrON's dietary questionnaires. The median maternal vitamin D intake was 665 International Units (IU)/day, while 25% reported intakes below the recommended 400 IU/day. Of the 224 infants in the cohort, 72% were exclusively breastfed, and 90% were receiving vitamin D supplements. Infants' median 25(OH)D was 96.0 nmol/L (interquartile ranges (IQR) 77.6-116.2), and 25% had 25(OH)D < 75 nmol/L. An adjusted linear regression model showed that, with a 100 IU increase in maternal vitamin D intake, infants' 25(OH)D increased by 0.9 nmol/L controlling for race, season, mid-pregnancy maternal 25(OH)D, birthweight, and whether the infant received daily vitamin D supplement (ß = 0.008, 95% confidence interval (CI) 0.002, 0.13). These results suggest that, to ensure infant optimal vitamin D status, not only do infants require a supplement, but women also need to meet current recommended vitamin D intake during breastfeeding.

The Current Recommended Vitamin D Intake Guideline for Diet and Supplements During Pregnancy Is Not Adequate to Achieve Vitamin D Sufficiency for Most Pregnant Women.

BACKGROUND: The aims of this study were to determine if pregnant women consumed the recommended vitamin D through diet alone or through diet and supplements, and if they achieved the current reference range vitamin D status when their reported dietary intake met the current recommendations. METHODS: Data and banked blood samples collected in second trimester from a subset of 537 women in the APrON (Alberta Pregnant Outcomes and Nutrition) study cohort were examined. Frozen collected plasma were assayed using LC-MS/MS (liquid chromatography-tandem mass spectrometry) to determine 25(OH)D2, 25(OH)D3, 3-epi-25(OH)D3 concentrations. Dietary data were obtained from questionnaires including a Supplement Intake Questionnaire and a 24-hour recall of the previous day's diet. RESULTS: Participants were 87% Caucasian; mean (SD) age of 31.3 (4.3); BMI 25.8 (4.7); 58% were primiparous; 90% had education beyond high school; 80% had a family income higher than CAN $70,000/year. 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3) were identified in all of the 537 plasma samples;3-epi-25(OH)D3 contributed 5% of the total vitamin D. The median (IQR) total 25(OH)D (D2+D3) was 92.7 (30.4) nmol/L and 20% of women had 25(OH)D concentration < 75 nmol/L. The median (IQR) reported vitamin D intake from diet and supplements was 600 (472) IU/day. There was a significant relationship between maternal reported dietary vitamin D intake (diet and supplement) and 25(OH)D and 3-epi-25(OH)D3 concentrations in an adjusted linear regression model. CONCLUSIONS: We demonstrated the current RDA (600 IU/ day) may not be adequate to achieve vitamin D status >75 nmol/L in some pregnant women who are residing in higher latitudes (Calgary, 51°N) in Alberta, Canada and the current vitamin D recommendations for Canadian pregnant women need to be re-evaluated.