Effects of Maternal Vitamin D Supplementation on the Maternal and Infant Epigenome

Abstract Introduction: Mothers and infants are at high risk for inadequate vitamin D status. Mechanisms by which vitamin D may affect maternal and infant DNA methylation are poorly understood. Objective: This study quantified the effects of vitamin D3 supplementation on DNA methylation in pregnant and lactating women and their breastfed infants. Materials and Methods: In this randomized controlled pilot study, pregnant women received vitamin D3 400 international units (IU) (n = 6; control) or 3,800 IU (n = 7; intervention) daily from late second trimester through 4–6 weeks postpartum. Epigenome-wide DNA methylation was quantified in leukocytes collected from mothers at birth and mother–infant dyads at 4–6 weeks postpartum. Results: At birth, intervention group mothers showed DNA methylation gain and loss at 76 and 89 cytosine–guanine (CpG) dinucleotides, respectively, compared to controls. Postpartum, methylation gain was noted at 200 and loss at 102 CpGs. Associated gene clusters showed strongest biologi...