Re: Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational studies and randomised trials
Vitamin D is one of the essential fat soluble vitamins required for normal mineralization and regulation of calcium and phosphorus metabolism. Its active form Calcitriol requires normal functioning liver and kidney for 25 hydroxylation and 1 hydroxylation respectively. It is now labeled as a steroid hormone which has specific cytosolic receptors in specific target organs like instestine, bone and kidney to exert its physiological functions. Other organs which have such receptors are subjected to calcitriol action possibly involving calcium and phosphorus linked metabolic functions. Metabolic studies involving such dietary components and also many such studies are carried out in isolated conditions or in testing specific research questions that are needed for fully evaluating the potential benefits derived from such a vitamin. Such an approach to find out what other outcomes can be derived from Vitamin D on human health apart from its known established effects on Calcium and phosphorus in bone metabolism may sometimes take away its real function to other generalized functions. Therefore let us be convinced that vitamin D is important for bone mineralization and demineralization.
Competing interests: No competing interests