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Providing perspectives on recent research into vitamins and nutritionals


Pregnancy, Zika Virus, Mosquitoes and B Vitamins

By Michael McBurney

With growing concerns about the impact of mosquito dissemination of Zika virus among pregnant women, one can forget that a lack of B vitamins can also stunt a baby’s brain development. Folate and B12 deficiency are linked to disruptions in myelination and  normal development of an infant’s central nervous system during pregnancy. Because of the high incidence of neural tube defects, folic acid fortification of enriched cereal grains and cereal grain products was mandated by law in the US in 1996. However, the law was limited to certain standards of identity (bread, rolls, and buns; wheat flours; corn meals; farina; rice; and macaroni and noodle products).

Mandatory folic acid fortification has been an effective public health intervention. However, corn masa flour is a staple for many women of child-bearing age and they were not benefiting from the fortification policy. By amending the food additive regulations to allow folic acid fortification of corn masa flour used in tortillas, tacos, tamales, corn chips and tortilla chips, fewer US women should be lacking folic acid.

Hopefully, other nations follow. In a systematic global review of the vitamin B12 literature (57 studies) in pregnant women, the overall prevalence of vitamin B12 insufficiency was 25% across all 3 trimesters. India, Nepal, Turkey, Greece, and parts of South America had the highest prevalence of vitamin B12 insufficiency. Among 11 studies with measurements of vitamin B12 status throughout the pregnancy, in 10 of them B12 concentrations decreased as pregnancy progressed.

During pregnancy, it is important to maintain concentrations of folic acid and vitamin B12 sufficient to support normal fetal development. Like mosquito control programs, food fortification is a public health intervention that can affect the health of future generations. If pregnancy is a possibility, it is important to consume 400-800 micrograms of folic acid daily. In other words, eat foods which have been processed and fortified with a ‘food additive’, i.e. folic acid, or use a dietary supplement.

Main Citation

Sukumar N, Rafnsson SB, Kandala N-B, Bhopal R, Yajnik CS, Saravanan P. Prevalence of vitamin B-12 insufficiency during pregnancy and its effect on offspring birth weight: a systematic review and meta-analysis. 2016 Am J Clin Nutr doi: 10.3945/ajcn.115.123083

Other Citations

Crider KS, Bailey LB, Berry RJ. Folic acid fortification – Its history, effect, concerns, and future directions. 2011 Nutrients doi: 10.3390/nu3030370

Black MM. Effects of vitamin B12 and folate deficiency on brain development in children. 2008 Food Nutr Bull 29:S126–S131

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