Major biologic function of activated vitamin D is to maintain normal blood levels of calcium and phosphorus, thus regulating bone mineralization. Research suggests that vitamin D may help in immunomodulation, regulating cell growth and 1,4 differentiation as well as some diverse unspecified functions. Overt vitamin D deficiency leads to hypocalcaemia, secondary hyperparathyroidism and increased bone turnover, which in prolonged and severe cases may cause rickets in children and osteomalacia in elderly.... JMS 2011;14(2):40-42