title: Vitamin D: an essential component for skeletal health.
abstract: Vitamin D deficiency is increasing worldwide. Ultraviolet rays are supposed to provide humans over 80% of our vitamin D requirement; the rest is received through diet and supplements. In addition to enhancing calcium absorption from the intestine and mineralization of the osteoid tissue, vitamin D has many other physiological effects, including neuromodulation, improving muscle strength and coordination, insulin release, immunity and prevention of infections, and curtailing cancer. Whether the increased incidence of vitamin D deficiency is related to increased incidences of nonskeletal disorders remains to be determined. Serum levels of 25-hydroxyvitamin [25(OH)D] above 30 ng/mL indicate vitamin D sufficiency. An additional 1,000 IU of vitamin D/day is sufficient for most lighter-skinned individuals, whereas an extra 2,000 IU/day is needed by the elderly and dark-skinned individuals to maintain normal 25(OH)D levels. Additional research is needed to clarify the relationship between vitamin D and the nonskeletal systems, nonclassic functions, and targets of vitamin D.
authors.affiliation: Division of Endocrinology, Metabolism & Nutrition, Department of Medicine, and UMDNJ, Robert Wood Johnson Medical School, Physiology and Integrative Biology, Graduate School of Biomedical Sciences, New Brunswick, New Jersey 08903-0019, USA. wimalasu@umdnj.edu
authors.forename: Sunil J
authors.initials: SJ
authors.lastname: Wimalawansa
mesh_terms: D001851:Bone Diseases, Metabolic / Q000517:prevention & control*; D001842:Bone and Bones / Q000378:metabolism; D019587:Dietary Supplements; D006801:Humans; D018167:Receptors, Calcitriol / Q000378:metabolism; D014807:Vitamin D / Q000378:metabolism / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000188:drug therapy / Q000378:metabolism / Q000517:prevention & control*
chemical_list: D018167:Receptors, Calcitriol; D014807:Vitamin D