Non-classical effects of vitamin D
Since the discovery of vitamin D, interest in role of vitamin D in human body is consistently growing, and there is increasing evidence that vitamin D is not only essential to bone health but may also be involved in physiology of many other tissues. Thus understanding of its aspects in particular tissues appears to be important because of possible contribution to pathophysiologic processes. Intracrine regulatory systems associated with widely expressed vitamin D metabolizing enzymes, ways of cellular intake and signal pathways involved are of particular interest. Association of local effects with vitamin D level in blood is under investigation on animal models as well as in clinical studies; values of vitamin D level that mediate extraskeletal effects should be determined. In this review, we discuss impact of vitamin D on immune function and its association with skin, nervous system, cardiovascular system, obesity and diabetes mellitus, cancer, reproductive function, prevention of falls and quality of life improvement.