Vitamin B12: An Intergenerational Story.

Vitamin B12 is a fascinating nutrient in that it is made by microbes but is essential for human metabolism. Humans can get it only from animal origin foods. Dietary deficiency rather than an absorption defect (Pernicious anemia, intrinsic factor defect) is the commonest cause of deficiency in the world, contributed by cultural and economic imperatives. Indians have a large prevalence of subclinical B12 deficiency due to vegetarianism. Birth cohort with long-term serial follow-up (Pune Maternal Nutrition Study) has helped reveal the life-course evolution of B12 deficiency: genetics, transplacental and lactational transfer from the mother, influence of family environment, rapid childhood and adolescent growth, and low consumption of milk all made a contribution. A novel association of low maternal B12 status was with fetal growth restriction and increased risk factors of diabetes in the baby. After demonstrating adequate absorption of small (2 μg) dose of vitamin B12, and a noticeable improvement of metabolic parameters in a pilot trial, we planned a supplementation trial in adolescents to improve outcomes in their babies (a primordial prevention called Pune Rural Intervention in the Young Adolescent). The results are awaited. The long-term effects in the babies born in the trial will contribute to a better understanding of the Developmental Origins of Health and Disease.