Prevention of Vitamin D Deficiency in Breastfed Infants

Vitamin D supplementation is recommended during pregnancy. But after birth, the ability to maintain healthy vitamin D levels in breastfed infants is more difficult, so vitamin D supplementation is generally recommended for breastfed infants.

In a study published online in the American Journal of Clinical Nutrition, researchers sought to determine the effect of three different doses of maternal vitamin D supplementation on infant serum vitamin D levels when taken during pregnancy and continuing for 8 weeks after birth.

The study included 226 normally healthy pregnant women who were randomly assigned to receive vitamin D dosages of 400 IU, 1000 IU, and 2000 IU per day from the second trimester until 8 weeks postpartum. The infants were not given vitamin D supplementation. Blood was collected for analysis at 8 weeks after birth.

The average serum vitamin D level in infants whose mothers took 2000 IU/day was higher (75 mmol/L or 30 ng/ml) than in 1000 IU/day group (52 mmol/L or 20.8 ng/ml) and the 400 IU/day group (45 mmol/L or 18 ng/ml). Only 2% of the infants born to mothers supplemented with 2000 IU were considered deficient (

The results of this study indicate that supplementation with 2000 IU/day is required beginning in gestation and during the first 8 weeks of breastfeeding to protect 98% of un-supplemented infants against vitamin D deficiency. Nearly half of un-supplemented infants of mothers taking 400 IU/day were vitamin D deficient after 8 weeks of breastfeeding.

March KM, Chen NN, Karakochuk CD, et al. Maternal vitamin D₃ supplementation at 50 μg/d protects against low serum 25-hydroxyvitamin D in infants at 8 wk of age: a randomized controlled trial of 3 doses of vitamin D beginning in gestation and continued in lactation. Am J Clin Nutr. 2015;102(2):402-10.