Laboratory evidence is presented of significant associations between reduced maternal serum folate and vitamin B12 levels and neural tube birth defects neural tube defects compared to referents. Median folate concentrations for case mothers were 36% lower than controls (9.8 ng/mL vs. 15 ng/mL). Maternal serum folate concentrations in quartiles above 9.5 ng/mL indicated significantly reduced risk (odds ratio = 0.4, odds ratio = 0.3, and odds ratio = 0.2). Likewise, the risk for neural tube defect decreased (odds ratio = 0.4, odds ratio = 0.3, and odds ratio = 0.2) in quartiles of sera vitamin B12 concentrations above 246 pg/mL.
http://www.ncbi.nlm.nih.gov/pubmed/20375932
We report on the effects of restricting the supply of specific B vitamins (i.e., B(12) and folate) and methionine, within normal physiological ranges, from the periconceptional diet of mature female sheep. We observed no effects on pregnancy establishment or birth weight, but this modest early dietary intervention led to adult offspring that were both heavier and fatter, elicited altered immune responses to antigenic challenge, were insulin-resistant, and had elevated blood pressure-effects that were most obvious in males.