Low maternal B12 status is associated with offspring insulin resistance but B12 or folate supplementation does not alter that risk

Abstract

There is concern that high maternal folate and low B12 status are associated with offspring insulin resistance (HOMA). We previously reported that maternal micronutrient supplementation had no effect on HOMA. Here, we report the association between maternal folate and B12 status and HOMA. In a substudy (n=1132) of a RCT of vitamin A alone (control) or with folic acid, folic acid-iron, folic acid-iron-zinc, or multiple micronutrient supplements, micronutrient status was assessed in early and late pregnancy (~10 and 36 wks gestation). In the offspring at 6–8 y, insulin resistance was estimated with the HOMA model using fasting insulin and glucose. Child HOMA was not associated with maternal plasma folate or B12 at early (folate β=0.05, p=0.48; B12 β=−0.05, p=0.42) or late (folate β=−0.02, p=0.77; B12 β=−0.09, p=0.21) pregnancy in continuous models. However, children whose mothers were B12 deficient (<148 pmol/L) at enrollment had a 26.7% increase in HOMA (p=0.02); this was not observed for low or high folate levels. Among B12 deficient women, micronutrient supplements containing folate with or without B12 among other nutrients did not affect HOMA (p>0.05 for all). Low B12 but not folate status during pregnancy is associated with insulin resistance in childhood, but maternal micronutrient supplementation that includes B12 does not alter that risk. Funded by the Gates Foundation and USAID.