Impact of vitamin B-12 deficiency during lactation on maternal and infant health.

Abstract

Vitamin B-12 is a “cobalamin”, a term that describes structures with a corrin ring which has a central cobalt atom, phosphate, a base, and ribose. One of several groups can be attached to the cobalt: cyanide, forming vitamin B-12; 5’deoxyadenosine, forming 5’ deoxyadenosylcobalamin; or a methyl group, forming methylcobalamin. Methylcobalamin is a cofactor for the conversion of homocysteine to methionine, and adenosylcobalamin is required for the conversion of methyl malonyl CoA to succinyl CoA. These cofactor functions explain why in vitamin B-12 deficiency there is elevated methylmalonic acid (MMA) in urine and serum, and plasma homocysteine (Hcy).