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Issue 3, 2017
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Sunlight exposure is just one of the factors which influence vitamin D status

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Abstract

Studies on the determinants of vitamin D status have tended to concentrate on input – exposure to ultraviolet B radiation and the limited sources in food. Yet, vitamin D status, determined by circulating concentrations of 25-hydroxyvitamin D (25(OH)D), can vary quite markedly in groups of people with apparently similar inputs of vitamin D. There are small effects of polymorphisms in the genes for key proteins involved in vitamin D production and metabolism, including 7-dehydrocholesterol reductase, which converts 7-dehydrocholesterol, the precursor of vitamin D, to cholesterol, CYP2R1, the main 25-hydroxylase of vitamin D, GC, coding for the vitamin D binding protein which transports 25(OH)D and other metabolites in blood and CYP24A1, which 24-hydroxylates both 25(OH)D and the hormone, 1,25-dihydroxyvitamin D. 25(OH)D has a highly variable half-life in blood. There is evidence that the half-life of 25(OH)D is affected by calcium intake and some therapeutic agents. Fat tissue seems to serve as a sink for the parent vitamin D, which is released mainly when there are reductions in adiposity. Some evidence is presented to support the proposal that skeletal muscle provides a substantial site of sequestration of 25(OH)D, protecting this metabolite from degradation by the liver, which may help to explain why exercise, not just outdoors, is usually associated with better vitamin D status.

Graphical abstract: Sunlight exposure is just one of the factors which influence vitamin D status

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Publication details

The article was received on 07 Sep 2016, accepted on 15 Jan 2017 and first published on 17 Jan 2017


Article type: Perspective
DOI: 10.1039/C6PP00329J
Citation: Photochem. Photobiol. Sci., 2017,16, 302-313
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    Sunlight exposure is just one of the factors which influence vitamin D status

    M. Abboud, M. S. Rybchyn, R. Rizk, D. R. Fraser and R. S. Mason, Photochem. Photobiol. Sci., 2017, 16, 302
    DOI: 10.1039/C6PP00329J

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