Corpus ID: 13722418

2 Photobiology of Vitamin D

  title={2 Photobiology of Vitamin D},
  author={Tai-Chi Chen and Zhiren Lu and Michael F Holick},
The major function of vitamin D (either vitamin D2 or D3) is to maintain healthy bone. Most humans obtain their vitamin D requirement through casual exposure of the skin to solar ultraviolet B and from dietary intake. The cutaneous synthesis of vitamin D is a function of 7-dehydrocholesterol concentration in epidermis, melanin pigmentation, and the solar zenith angle which depends on latitude, season, and time of day. Our recent study also indicates that altitude may influence the production of… Expand


Factors that influence the cutaneous synthesis and dietary sources of vitamin D.
The results provide useful global guidelines for obtaining sufficient vitamin D3 by cutaneous synthesis and from dietary intake to prevent vitamin D deficiency and its health consequences, ensuing illness, especially, bone fractures in the elderly. Expand
Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation.
Vitamin D3 proved to be exquisitely sensitive to sunlight, and once formed in the skin, exposure to sunlight resulted in its rapid photodegradation to a variety of photoproducts, including 5,6-transv vitamin D3, suPRasterol I, and suprasterol II. Expand
Vitamin D: a D-Lightful health perspective.
Health professionals need to be aware of the vitamin D deficiency pandemic and guidelines for sensible sun exposure and supplemental vitamin D of 800-1000 IU/day are needed. Expand
The vitamin D deficiency pandemic and consequences for nonskeletal health: mechanisms of action.
  • M. Holick
  • Medicine
  • Molecular aspects of medicine
  • 2008
The revelation that the colon, breast, prostate, macrophages and skin among other organs have the enzymatic machinery to produce 1,25-dihydroxyvitamin D provides further insight as to how vitamin D plays such an essential role for overall health and well being. Expand
Vitamin D and Skin Physiology: A D‐Lightful Story
The associations regarding increased risk of common deadly cancers, autoimmune diseases, infectious diseases, and cardiovascular disease with living at higher latitudes and being prone to vitamin D deficiency should alert all health care professionals about the importance of vitamin D for overall health and well being. Expand
Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin.
The dramatic influence of changes in solar UVB radiation on cutaneous vitamin D3 synthesis is quantified and the latitudinal increase in the length of the "vitamin D winter" during which dietary supplementation of the vitamin may be advisable is indicated. Expand
Chronic sunscreen use decreases circulating concentrations of 25-hydroxyvitamin D. A preliminary study.
It is suggested that long-term use of PABA may be associated with low body stores of vitamin D in some persons, as seen in two PABA users and in none of the controls. Expand
Skin-Pigment Regulation of Vitamin-D Biosynthesis in Man
The known correlation between the color of human skin and latitude (Fig. 2) is explainable in terms of two opposing positive adaptations to solar ultraviolet radiation, weak in northern latitudes inExpand
Solar ultraviolet B radiation and photoproduction of vitamin D3 in central and southern areas of argentina
  • M. Ladizesky, Zhiren Lu, +4 authors C. Mautalen
  • Chemistry, Medicine
  • Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
  • 1995
It is concluded that in Ushuaia there is a prolonged “vitamin D winter” during which cutaneous synthesis of vitamin D is absent, leading to lower serum values of 25(OH)D and contributing to the higher incidence of rickets. Expand
Sunscreens suppress cutaneous vitamin D3 synthesis.
Results indicate that the sunscreen interferred with the cutaneous production of vitamin D3, and prevented the photoisomerization of 7-dehydrocholesterol to previtamin D3 in human skin slices in vitro. Expand