Maternal vitamin D supplementation to meet the needs of the breastfed infant: a systematic review.

Maternal vitamin D insufficiency during lactation, related to lack of sun exposure and minimal intake of vitamin D from the diet, contributes to low breast milk vitamin D content and, therefore, infant vitamin D deficiency. The objective of this review was to examine the literature regarding evidence for achieving maternal vitamin D status that promotes sufficient vitamin D transfer from mother to infant exclusively from breast milk. PubMed and CINAHL databases were searched using the terms lactation or breastfeeding or milk, human and vitamin D. The resulting articles were further limited to those written in English, published within the last 10 years, and involving clinical or randomized controlled trials of humans. The search yielded 13 studies, 3 of which provide evidence for maternal intake of vitamin D and the correlation with exclusively breastfed infants' serum 25-hydroxyvitamin D level. A strong positive correlation exists between maternal vitamin D intake during exclusive breastfeeding and infant serum 25-hydroxyvitamin D levels. There is support to conclude that when maternal vitamin D intake is sufficient, vitamin D transfer via breast milk is adequate to meet infant needs. In the reviewed studies, doses up to 10 times the current recommended daily intake of vitamin D were needed to produce sufficient transfer from mother to breastfed infant. Further research is needed to refine the dose and gestational timing of maternal vitamin D supplementation. Due to the high rates of vitamin D deficiency during lactation and the correlations between vitamin D deficiency and multiple diseases, providers should consider monitoring lactating mothers' vitamin D status.