Vitamin D Supplementation: For Mother or Baby?

Vitamin D supplementation is recommended for breast-fed babies starting in the neonatal period to prevent deficiency (25-hydroxy vitamin D [25(OH)D] level <50 nmol/L) and rickets, but compliance is often poor. Researchers randomized 216 mother-infant pairs (infant age, about 1 month) who planned to breast-feed exclusively to receive 400 IU vitamin D per day for the mother (from a prenatal multivitamin) and 400 IU for the infant (from oral drops), or to receive 6400 IU per day (including 400 IU from a prenatal multivitamin) for the mother and placebo for the infant.

At baseline, mean 25(OH)D levels were 86 nmol/L in mothers and 36 nmol/L in babies; 75% of babies were deficient. Some black and Hispanic babies had undetectable levels (<2.5 nmol…