Vitamin B12 (cobalamin) is an essential coenzyme for nucleic acid synthesis. Animal protein is the major dietary source of vitamin B12. Deficiency of vitamin B12 leads to megaloblastic anemia, degeneration of the brain, spinal cord, peripheral nerves, and abnormalities of epithelial tissues. Two factors are necessary for the cure of megaloblastic anemia: one in food (extrinsic factor) and one in gastric juice (intrinsic factor). The extrinsic factor is vitamin B12. Intrinsic factor (a glycoprotein secreted by gastric parietal cells) ensures cobalamin absorption by receptors in the terminal ileum. Vitamin B12 is actively transported across the placenta. Neonates have high serum levels and significant liver stores of vitamin B12.
The neonates born to mothers with deficiency of vitamin B12 have deficiency of this vitamin. Pregnant women in resource-poor areas have low vitamin B12 status which is associated with adverse pregnancy outcomes, including anemia, low birth weight, and intrauterine growth retardation. Supplementation of vitamin B12 had significantly higher plasma of vitamin B12 in mothers and neonates. A single intramuscularly injection of vitamin B12 of between 250 µg and 1mg and a dietary intake of 1 µg/kg per day vitamin B12 is sufficient to combat vitamin B12 deficiency. Mean DNA damage scores in infants with vitamin B12 deficiency and their mothers were significantly higher before than after supplementation with vitamin B12. There were correlations between the infants' and their mothers' DNA damage scores. The aim of this study is the review of the effects of vitamin B12 in neonates and young infants.