Abstract
This article reviews vitamin B12 (B12) status and deficiency during pregnancy and lactation, its effect on pregnancy, and the health of the offspring, with the aim to underscore the need for a sustainable strategy to improve maternal and infant vitamin B12 status of low and middle income countries. Vitamin B12 is a basic nutrient required for maintenance of normal erythropoiesis, cell reproduction, nucleoprotein and myelin synthesis. B12 deficiency is associated with adverse pregnancy outcomes and neurodevelopmental morbidity during infancy. Very few studies have indicated that B12 deficiency may contribute to altered immune responses in animals and humans. Additionally, no studies have shown modulation of infant motor development in response to maternal B12 supplementation. Despite the high global prevalence of B12 deficiency and its serious effects on pregnant women and offspring, there is still no consensus on the cut-off of biochemical markers (indicator of B12 deficiency) to correctly diagnose B12 deficiency in mother-infant dyad. Also, the optimum dose of B12 to normalize B12 status of mother-infant pairs in a deficient population is not known yet. In addition, markers of other functions such as neurodevelopment, immune response that may be affected by vitamin B12 deficiency should be measured to determine if they respond to supplementation. Thus, there is an urgent need to conduct more trials to find out the optimum dose, to investigate whether intervention with such pre-and post natal vitamin B12 supplementation would improve maternal, neonatal and child health outcomes in population at risk, giving emphasis on neurological processes, immune functions and epigenetic modifications. Other strategies including food based approach also require evidence based results which will help to understand effectiveness of a targeted and well-designed intervention among this population.
Highlights
Vitamin B12 (Cyanocobalamin), a water-soluble vitamin is an essential nutrient required for maintenance of normal erytrhropoiesis, nucleoprotein and myelin synthesis, cell reproduction and normal growth
This review summarizes literature relating to B12 status and deficiency during pregnancy and lactation, its effect on pregnancy, and the health of the offspring, with the aim to underscore the need for a sustainable strategy to improve maternal and infant vitamin B12 status of low and middle income countries
Placental lactogen acts as a regulator of increased Intrinsic Factor (IF)-mediated vitamin B12 binding to ileal binding sites by recruiting already existing cryptic receptor rather than stimulating the synthesis of new one [9]
Summary
Vitamin B12 (Cyanocobalamin), a water-soluble vitamin is an essential nutrient required for maintenance of normal erytrhropoiesis, nucleoprotein and myelin synthesis, cell reproduction and normal growth. Vitamin B12 is a necessary cofactor in the methionine synthase reaction, which converts homocysteine into methionine. Deficiency of vitamin B12 could elevate plasma homocysteine which is a risk factor for cardiovascular diseases. Methionine is the required precursor for the formation of S-adenosylmethionine, a universal methyl donor essential for methylation of phospholipids, neurotransmitters, amines, DNA, RNA and myelin basic protein. A reduction in this important methyl donor causes impaired DNA methylation that may contribute to altered fetal metabolic programming and increased risk for chronic diseases later in life. In B12 deficiency, the concentration of methylmalonyl CoA is elevated and forms the by-product methylmalonic acid (MMA). Vitamin B12 insufficiency may influence carbohydrate and lipid metabolic pathways [1]
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