Submitted to: Breastfeeding Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2006
Publication Date: 3/20/2006
Citation: Basile, L.A., Taylor, S.N., Wagner, C.L., Horst, R.L., Hollis, B.W. 2006. The effect of high-dose vitamin D supplementation on serum vitamin D levels and milk calcium concentration in lactating women and their infants. Breastfeeding Medicine. 1(1):27-35.
Interpretive Summary: Vitamin D deficiency in infants and children, specifically nutritional rickets, was thought to be disappearing. However, hypovitaminosis D is more prevalent than suspected in both children and adults. Hypovitaminosis D occurs because 1) sun exposure is extremely limited for both mothers and infants; and 2) dietary supplementation at the current dietary recommended intake of 400 IU/d is inconsequential. Vitamin D levels also vary according to race/degree of pigmentation, season, and latitude. The objectives of this study were to improve vitamin D status in lactating women and their recipient infants and measure calcium concentration of breast milk as a function of vitamin D supplementation regimen. In this study we determined that high doses of vitamin D were effective in improving vitamin D status in fully breastfeeding mothers to optimal levels without evidence of toxicity. We also observed that breast milk calcium concentration declines during 1 to 4 months, and was independent of maternal vitamin D status.
Technical Abstract: Objective: Improve vitamin D status in lactating women and their recipient infants, and measure breast milk calcium concentration ([Ca]) as a function of vitamin D regimen. Design/Methods: Fully breastfeeding mothers were randomized at one month postpartum to 2,000 (n = 12) or 4,000 (n = 13) IU/day vitamin D for 3 months to achieve optimal vitamin D status [serum 25(OH)D >/= 32 ng/mL (80 nmol/L)]. Breast milk [Ca], maternal and infant serum 25(OH)D and serum Ca, and maternal urinary Ca/Cr ratio were measured monthly. Results: Mothers were similar between groups for age, race, gestation, and birth weight. 25(OH)D increased from 1 to 4 months in both groups (mean +/- SD): +11.5 +/- 2.8 ng/mL for group 2,000 (p = 0.002) and +14.4 +/- 3.3 ng/mL for group 4,000 (p = 0.0008). 4,000 IU/day regimen was more effective in raising both maternal and infant serum levels and breast milk anti-rachitic activity than 2,000 IU/day regimen. Breast milk [Ca] fell with continued lactation through 4 months in the 2,000 IU and 4,000 IU groups. Decline in breast milk [Ca] was not associated with vitamin D dose (p = 0.73) or maternal 25(OH)D (p = 0.94). No mother or infant experienced vitamin D-related adverse events and all laboratory parameters remained in the normal range. Conclusions: High dose vitamin D was effective in increasing 25(OH)D levels in fully breastfeeding mothers to optimal levels without evidence of toxicity. Breast milk [Ca] and its decline in both groups during 1 to 4 months, were independent of maternal vitamin D status and regimen. Both the mother and her infant attained improved vitamin D status and maintained normal [Ca].