Vitamin D and Immunity: A comprehensive review of its impact on autoimmunity, allergy suppression, antimicrobial defense, and cancer inhibition.

Vitamin D, commonly known for its impact on bone metabolism, is vital in various bodily processes, including regulating immune responses. The actions of vitamin D are carried out through its receptor, found in cells of different human organs and tissues, particularly in most immune system cells and epithelial cells. After binding to the receptor, vitamin D forms a complex with vitamin A and its receptor in the cytoplasm.