Thanks For The Vitamins, Mom!
Babies depend on their mothers for so many things: comfort, support, protection, and of course, nourishment. The contents of mom’s diet have a profound impact on baby’s health now and in the future – look at the case of maternal folic acid intake and the risk of neural tube defects or the growing body of literature suggesting a relationship between the maternal diet and offspring cancer risk. But really, the simplest thing mom wants to ensure is that her baby has enough nutrients to support healthy development and that the baby is born free of deficiency. Are the current recommendations providing enough to make sure of this?
Supplementation is an effective way to improve nutrient intakes, particularly for nutrients of concern such as vitamin D. March and colleagues sought to determine whether maternal vitamin D supplementation during pregnancy protected against low infant serum vitamin D concentrations in the infant after birth. These investigators took a cohort of pregnant women and provided them with either 10, 25, or 50 mcg (400, 1000, or 2000 IU) of vitamin D beginning at 13-24 weeks gestation until 8 weeks postpartum, and examined the impact on baby’s vitamin D status (as measured through infant cord blood vitamin D concentration).
The results were somewhat surprising: supplementation improved mom’s vitamin D blood concentrations only in those receiving 25 or 50 mcg/day both at the end of pregnancy and 8 weeks postpartum – however, no significant changes in mom’s vitamin D status was observed for those receiving 10 mcg/day. When they looked at the prevalence of deficiency (serum vitamin D < 30nmol/L) among the infants who were exclusively breastfed, just 2% of infants born to moms receiving 50 mcg/day were vitamin D deficient, while 16% and 43% of infants born to moms receiving 25 and 10 mcg/day were vitamin D deficient.
These findings particularly concerning when you remember that the current IOM recommendation for vitamin D for pregnant women is 15 mcg/day (600 IU) – considering that women reported a dietary (non-supplemental) intake of 5 mcg/day, then the women in the 10 mcg/day group were achieving the current IOM recommended intake for vitamin D when you account for both dietary and supplemental sources. The fact that this didn’t improve mom’s vitamin D status and that such a large proportion of their children were still vitamin D deficient is troubling to say the least.
Achieving adequate vitamin D intake, and status by extension, is troublesome for many Americans: more than 90% of us don’t get enough vitamin D from food alone, after all. Pregnant women are a particularly vulnerable population, especially when we remember that they are eating for two. So what do we tell them? We know that for pregnant women, achieving proper nutrient intake is critical for supporting healthy development for the baby. Nutrients like folic acid, DHA, and vitamin D play key roles in supporting healthy growth for baby. If you’re a pregnant woman, make sure that you’re getting enough vitamin D – at the very least meeting the current RDA. And if you supplemented with a little more, it might not be such a bad thing for both you and your baby.
March KM, Chen NN, Karakochuk CD, et al. Maternal vitamin D3 supplementation at 50 mcg/day protects against low serum 23-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; (epub ahead of print).
Ciappio ED, Mason JB, Crott JW. Maternal one-carbon nutrient intake and cancer risk in offspring. Nutr Rev 2011; 69(10): 561-571.
Fulgoni VL, Keast DR, Bailey RL, Dwyer J. Foods, fortificants, and supplements: where do Americans get their nutrients? J Nutr 2011; 141: 1847-1854.