Trying to Unravel the Role of B Vitamins (and Genetics) in Pregnancy
When a baby is developing in the womb, sometimes the spinal column does not develop properly. In the United States, 8 babies are born daily with a defect in the development of the brain and spinal column. Folate deficiency is known to increase the risk of spina bifida and other neural tube defects (NTDs) but it is not the only risk factor. This fact is eloquently personalized by Amanda Kern as she discusses her son Chance in her blog “To the doctor who believes folic acid can prevent spina bifida and a lifetime of disability”.
Amanda reminds me that there is much to learn about the causes of NTDs and spina bifida. We know that many B vitamins are involved in one-carbon metabolism, especially important during pregnancy as newborns develop. Disruptions in one-carbon metabolism impair DNA synthesis and can affect brain and neural development in utero.
We have the most evidence for folate. Based on epidemiology and research, many countries have mandated folate fortification of flours and health professionals recommend folate supplementation during pregnancy.
Vitamin B12 is known to be essential for folate metabolism. In one of our most read blogs, Julia Bird summarized controversies in measuring B12 discussed at the 9th International Conference on Homocysteine and One Carbon Metabolism in Ireland in 2013. There is emerging evidence of a greater B12 requirement during pregnancy and lactation.
Vitamin B6 should not be overlooked as it too is involved in one-carbon metabolism. Metabolic consequences of mild-to-moderate B6 deficiency have metabolic consequences in women. Oral contraceptive use also affects one-carbon metabolism. Could prior contraceptive use affecting maternal B6 status impact one-carbon metabolism and fetal development? This is an important question.
Choline status and genetics should not be overlooked. Maternal choline status during pregnancy may be very relevant. However, as Amanda Kern reminds me, our hearts and hopes rest on more than folate status. We need to know more about the intersection of genetics, and all of the B vitamins on one-carbon metabolism, especially during pregnancy which involves providing nutrients for more than one adult.
Rios-Avila L, Coats B, Chi Y-Y, Midttun O, Ueland PM, Stacpoole PW, Gregory III JF. Metabolite profile analysis reveals association of vitamin B-6 with metabolites related to one-carbon metabolism and tryptophan catabolism but not with biomarkers of inflammation in oral contraceptive users and reveals the effects of oral contraceptives on these processes. 2015 J Nutr doi: 10.3945/jn.114.201095
Grant E, Stover D, Field M, Stover P. The effects of 4-hydroxy-5-methyltetrahydrofolate on folate-mediated one-carbon metabolism. 2015 The FASEB J 29 (1) S 884.11
Ganz A, Shields K, Yan J, Cohen V, Swersky C, Formin V, Stover J, Lovesky J, Mohan S, Lopez Y, Chuang J, Carrier B, Vitiello G, Malysheva O, Caudill M. Genetic factors influence choline dynamics in pregnant and lactating women. 2015 The FASEB J 29 (1) S 919.12
Bae S, West AA, Yan J, Jiang X, Perry CA, Malysheva O, Stabler SP, Allen RH, Caudill MA. Vitamin B12 status differs among pregnant, lactating, and control women with equivalent nutrient intakes. 2015 J Nutr doi: 10.3945/jn.115.210757
Masih SP, Plumptre L, Ly A, et al. Pregnant Canadian women achieve recommended intakes fo one-carbon nutrients through prenatal supplementation but the supplement composition, including choline, requires reconsideration. 2015 J Nutr doi: 10.3945/jn.115.211300
Visentin CE, Masih S, Plumptre L, Malysheva O, Nielsen DE, Sohn K-J, Ly A, Lausman AY, Berger H, Croxford R, El-Sohemy A, Caudill MA, O’Connor DL, Kim Y-In. Maternal choline status, but not fetal genotype, influences cord plasma choline metabolite concentrations. 2015 J Nutr doi: 10.3945/jn.115.211136