Vitamin D

 Vitamin D insufficiency affects almost 50% of the population worldwide.An estimated 1 billion people worldwide, across all ethnicities and age groups, have a vitamin D deficiency (VDD).This pandemic of hypovitaminosis D can mainly be attributed to lifestyle and environmental factors that reduce exposure to sunlight, which is required for ultraviolet-B (UVB)-induced vitamin D production within the skin. Black people absorb more UVB within the melanin of their skin than do White race and, therefore, require more sun exposure to supply an equivalent amount of vitamin D . The high prevalence of vitamin D insufficiency may be a particularly important public health issue because hypovitaminosis D is an independent risk factor for total mortality within the general population.Emerging research supports the possible role of vitamin D against cancer, heart condition , fractures and falls, autoimmune diseases, influenza, type-2 diabetes, and depression. Many health care providers have increased their recommendations for vitamin D supplementation to a minimum of 1000 IU. A meta-analysis published in 2007 showed that vitamin D supplementation was related to significantly reduced mortality.In this review, we'll specialise in the biology of vitamin D and summarize the mechanisms that are presumed to underlie the connection between vitamin D and its clinical implications.