Are Pregnant Women Getting Enough Vitamin B12?
Pregnancy and breastfeeding are incredibly special times in a woman’s life. The Dietary Reference Intakes (DRIs) make intake recommendations based on pregnancy and lactation status, which generally speaking are higher than for non-pregnant/lactating women of childbearing age. But are they set high enough?
Enter Sajin Bae and colleagues, who sought to determine the impact of pregnancy and lactation on vitamin B12 status. This group gave pregnant, lactating, and control women a diet containing 8.6 mcg/day vitamin B12 for 10-12 weeks. As expected, the serum vitamin B12 concentrations increased significantly with the test diet in control women. In lactating women, no significant change was observed, yet their status was significantly higher than the control and pregnant women throughout the study. Interestingly, pregnant women had a lower status throughout the study, and not much change was observed in their serum vitamin B12 concentrations. And since the total intake of 8.6 mcg/day was roughly 3x higher than the RDA for pregnant women (2.6 mcg/day), the fact that vitamin B12 status did not change and remained towards the lower end of normal suggests that the needs for vitamin B12 may in fact be higher in this group.
So put simply this study suggests that both pregnancy and lactation influenced vitamin B12 status, and that pregnant/lactating women may require additional vitamin B12 above the current RDA. Why is this important? Although we have had a DRI for pregnant and lactating women for vitamin B12 for just about 15 years, this is the first time that vitamin B12 status in pregnant women has been assessed under a controlled diet/supplement intervention. And it turns out that when we look to nutrient status, the data suggests that way may need more than we originally thought. Nutrient status matters, and efforts to increase our use of these markers in studies is important for advancing nutrition science.
Bae S, West AA, Yan J, et al. Vitamin B12 status differs among pregnant, lactating, and control women with equivalent nutrient intakes. J Nutr 2015; 145: 1507-1514.