Vitamin B-12 Status Differs among Pregnant, Lactating, and Control Women with Equivalent Nutrient Intakes. Issue 7 (20th May 2015)

• Record Type: Journal Article
• Authors: Bae, Sajin; West, Allyson A; Yan, Jian; Jiang, Xinyin; Perry, Cydne A; Malysheva, Olga; Stabler, Sally P; Allen, Robert H; Caudill, Marie A
• Is Part Of: Journal of nutrition. Volume 145:Issue 7(2015)
• Page Start: 1507
• Page End: 1514
• Publication Date: 2015-05-20
• Subjects: vitamin B-12 -- pregnancy -- lactation -- holotranscobalamin -- homocysteine -- methylmalonic acid -- controlled feeding study -- reproductive state -- women of reproductive age; Nutrition -- Periodicals; Diet -- Periodicals; 613.205
• DOI: 10.3945/jn.115.210757
• Languages: English
• ISSNs: 0022-3166

Abstract

Abstract: Background: Limited data are available from controlled studies on biomarkers of maternal vitamin B-12 status. Objective: We sought to quantify the effects of pregnancy and lactation on the vitamin B-12 status response to a known and highly controlled vitamin B-12 intake. Methods: As part of a 10–12 wk feeding trial, pregnant (26–29 wk gestation; n = 26), lactating (5 wk postpartum; n = 28), and control (nonpregnant, nonlactating; n = 21) women consumed vitamin B-12 amounts of ∼8.6 μg/d [mixed diet (∼6 μg/d) plus a prenatal multivitamin supplement (2.6 μg/d)]. Serum vitamin B-12, holotranscobalamin (bioactive form of vitamin B-12), methylmalonic acid (MMA), and homocysteine were measured at baseline and study-end. Results: All participants achieved adequate vitamin B-12 status in response to the study dose. Compared with control women, pregnant women had lower serum vitamin B-12 (−21%; P = 0.02) at study-end, whereas lactating women had higher ( P = 0.04) serum vitamin B-12 throughout the study (+26% at study-end). Consumption of the study vitamin B-12 dose increased serum holotranscobalamin in all reproductive groups (+16–42%; P ≤ 0.009). At study-end, pregnant (vs. control) women had a higher holotranscobalamin–to–vitamin B-12 ratio ( P = 0.04) with ∼30% (vs. 20%) of total vitamin B-12 in the bioactive form. Serum MMA increased during pregnancy (+50%; P < 0.001) but did not differ by reproductive state at study-end. Serum homocysteine increased in pregnant women (+15%; P = 0.009) but decreased in control and lactating women (−16–17%; P < 0.001). Despite these changes, pregnant women had ∼20% lower serum homocysteine than the other 2 groups at study-end ( P ≤ 0.02). Conclusion: Pregnancy and lactation alter vitamin B-12 status in a manner consistent with enhanced vitamin B-12 supply to the child. Consumption of the study vitamin B-12 dose (∼3 times the RDA) increased the bioactive form of vitamin B-12, suggesting that women in these reproductive states may benefit from vitamin B-12 intakes exceeding current recommendations. This trial was registered at clinicaltrials.gov as NCT01127022.