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TalkingNutrition

Providing perspectives on recent research into vitamins and nutritionals

folicacid-microscope

Pass the Synthetic B Vitamins Please

By Michael McBurney

Vitamin B12 is synthesized  by bacteria in our gut or obtained by eating meat, dairy, eggs and fish. When people do not eat animal products, vitamin B12 intake can be low. In the blood, vitamin B12 is primarily bound to transcobalamin and transported to cells. Within cells,  vitamin B12 (cobalamin) and its other forms, methylcobalamin and adenosylcobalamin, serve as cofactors to methionine synthase, an enzyme involved in the methylation of DNA and histone proteins. Vitamin B12  metabolites regulate gene expression and are particularly important for brain development.

Low prenatal folate concentrations are associated with smaller total brain volumes of children and cognitive development. A new study finds an unexpected decrease in brain cortical cobalamin and methylcobalamin concentrations across the lifespan, as well as premature decreases in individuals with autism and schizophrenia.

Methylcobalamin, the most abundant cobalamin form in the brain, was found to be 12 times lower  in the brains of healthy older people than healthy younger people. Children under 10y with autism had total brain cobalamin concentrations that were 3 times lower than non-autistic children (3.1 vs 8.9 pmol/mg protein). The authors write, “Taken together, our results suggest that the well-documented systemic deficit of GSH in autism, as measured in the blood, may be linked to decreased vitamin B12 transport into the brain.”

Zhang et al note that the decreased brain vitamin B12 in autism is analogous to cerebrate folate deficiency syndrome. Because of its role in brain stem development, the US government recommended that all women of childbearing age consume 400µg of synthetic folic acid in 1992 and then mandated the addition of synthetic folic acid to cereal grains in 1998. These actions have significantly reduced the number of children born with neural tube defects.

These studies demonstrate the unequivocal importance of folic acid and vitamin B12. The fortification of foods with synthetic  B vitamins and/or the consumption of dietary supplements with these vitamins is essential. Can one obtain these vitamins naturally from some foods? Yes but food restrictions may limit intake. As these citations demonstrate, suboptimal B vitamin levels can profoundly affect cellular function. Help maintain your brain by consuming recommended amounts of B vitamins.

Main Citations

Ars CL, Nijs IM, Marroun HE, Muetzel R, Schmidt M, Steenweg-de Gaaff J, van der Lugt A, Jaddoe VW, Hofman A, Steegers EA, Verhulst FC, Tiemeier H, White T. Prenatal folate, homocysteine and vitamin B12 levels and child brain volumes, cognitive development and psychological functioning: the Generation R Study. 2016 Br J Nutr doi: 10.1017/S0007114515002081

Zhang Y, Hodgson NW, Trividi MS, Abdolmaleky HM, Fournier M, Cuenod M, Quang Do K, Deth RC. Decreased brain levels of vitamin B12 in aging, autism and schizophrenia. 2016 PLos One doi: 10.1371/journal.pone.0146797

Other Citations

Williams LJ, Mai CT, Edmonds LD, Shaw GM, Kirby RS, Hobbs CA, Sever LE, Miller LA, Meaney FJ, Levitt M. Prevalence of spina bifida and anencephaly during the transition to mandatory folic acid fortication in the United States. 2002 Clin Molec Teratol doi: 10.1002/tera.10060

Williams J, Mai CT, Mulinare J, Isenburg J, Flood TJ, Ethan M, Frohnert B, Kirby RS. Updated estimates of neural tube defects prevented by mandatory folic acid fortification – United States, 1995-2011. 2015 MMWR 64(01):1-5


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