Role of vitamin D in the immune system

Classically, the only roles attributed to vitamin D have been regulation of intestinal calcium absorption and maintenance of skeletal homeostasis. This review examines the new evidence describing a regulatory role for vitamin D (1,25-dihydroxyvitamin D) in immune cell functions along with research that has linked immune cell functions with skeletal homeostasis. The possible significance of this evidence with respect to the parturient dairy cow is discussed.