An evidence-based study for assessment of the effects of Vitamin D in the treatment of vitiligo

The active form of vitamin D, namely― 1,25-dihydroxy vitamin D acts as a steroid hormone that regulates a myriad of biological responses through its nuclear receptor (VDR). The VDR occupies 2,776 positions in the human genome; making up about 10% of the human genes directly and/or indirectly responsive to vitamin D. Similarly, a wide range of human cells like that of muscle, bone, skin, blood vessels, brain, colon, breast, prostate, and immune cells encode for the enzyme 25-hydroxyvitamin D-1 α-hydroxylase suggesting that the extra-renal intracrine and paracrine 1,25(OH)2D3 synthesis may critically affect the activities of many tissues and organs. Cumulative data originating from several in-vivo as well as clinical studies have associated low vitamin D status (as assessed by the levels of circulating 25-hydroxyvitamin D3 or 25(OH)D3) not only with bone-related disorders such as rickets and osteoporosis but also with several infectious diseases as well as cancer, secondary hyperparathyroidism and autoimmune diseases like multiple sclerosis, systemic lupus erythematosus, psoriasis, rheumatoid arthritis, and type 1 diabetes. Vitiligo is a pigmentary disorder of autoimmune origin that is characterized by anomalous loss of functional melanocytes from the epidermis. Although the exact etiological causes of vitiligo are yet to be known, numerous studies over the years have indicated an interrelationship of vitamin D with vitiligo. Vitamin D influences skin pigmentation by increasing tyrosinase activity and melanogenesis and its immunoregulatory functions, thereby exerting a positive response in the treatment of vitiligo. Therefore, this review article aims to discuss the various interventional studies that have been carried out so far to observe the effect of oral and topical administration of Vit D in the management and treatment of vitiligo. Understanding its mechanisms will facilitate the integration of genomic information into the workup of individualized patient care and make better clinical and nutritional decisions.