Sunlight, UV-radiation, vitamin D and skin cancer: how much sunlight do we need?

Abstract

Vtamin D is the sunshine vitamin for good reason. During exposure to sunlight, the utraviolet B photons enter the skin and photolyze 7-dehydrocholesterol to previtamin D3 which in turn is isomerized by the body's temperature to vitamin D3. Most humans have depended on sun for their vitamin D requirement. Skin pigment, sunscreen use, aging, time of day, season and latitude dramatically affect previtamin D3 synthesis. Vitamin D deficiency was thought to have been conquered, but it is now recognized that more than 50% of the world's population is at risk for vitamin D deficiency. This deficiency is in part due to the inadequate fortification of foods with vitamin D and the misconception that a healthy diet contains an adequate amount of vitamin D. Vitamin D deficiency causes growth retardation and rickets in children and will precipitate and exacerbate osteopenia, osteoporosis and increase risk of fracture in adults. The vitamin D deficiency has been associated pandemic with other serious consequences including increased risk of common cancers, autoimmune diseases, infectious diseases and cardiovascular disease. There needs to be a renewed appreciation of the beneficial effect of moderate sunlight for providing all humans with their vitamin D requirement for health.

• Authors: Michael F Holick
• Journal: Advances in experimental medicine and biology (Adv Exp Med Biol) Vol. 624 Pg. 1-15 ( 2008) ISSN: 0065-2598 [Print] United States
• PMID: 18348443 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Review)

Chemical References

• Vitamins
• Vitamin D

Topics

• Humans
• Skin Neoplasms (etiology, prevention & control)
• Sunlight (adverse effects)
• Ultraviolet Rays (adverse effects)
• Vitamin D (biosynthesis)
• Vitamin D Deficiency (prevention & control)
• Vitamins (biosynthesis)