The Skin and Vitamin D
November 2012
TLDR Vitamin D is made by the skin, helps control various body functions, and affects skin health and immunity.
The document from 11 years ago discussed the role of vitamin D in the skin. The skin is the primary source of vitamin D for the body, which is formed from the precursor 7-dehydrocholesterol under the influence of ultraviolet radiation. Vitamin D, when converted to its active metabolites, regulates not only bone mineral homeostasis but also differentiation and proliferation of numerous cell types, hormone secretion, and immune function. The keratinocytes of the skin are unique as they not only produce vitamin D but also metabolize it to active metabolites and respond to it through the vitamin D receptor (VDR). Vitamin D and/or its receptor regulate numerous skin functions including inhibition of proliferation, stimulation of differentiation, promotion of innate immunity, regulation of the hair follicle cycle, and suppression of tumor formation. These actions are regulated by different coregulators including the coactivators DRIP and SRC, an inhibitor called hairless (Hr), and β-catenin. Different coregulators are involved in different VDR regulated functions.
