Sunlight, Vitamin D and Sunscreens
Over the past few years there has been considerable media coverage about the influence of vitamin D and sun exposure on various diseases, including different types of cancer. The incidence of and mortality from many cancers have been reported to be reduced with decreasing latitude.11 Holick hypothesized that this reduction is related to higher vitamin D production from increased sun exposure. Vitamin D synthesis is a UVB phenomenon and sunscreens are usually very effective in protecting against UVB. Few prospective studies on the role of vitamin D and sun exposure in cancer prevention have been published. Additional studies are necessary to address issues such as the optimal amount of vitamin D needed to have beneficial effects and the role of oral vitamin D intake versus vitamin D synthesis following sun exposure.
Sun avoidance and the adequate use of high SPF and high UVA protection sunscreens on all exposed skin areas may still be appropriate for a kidney transplant patient who already has had multiple invasive squamous cell carcinomas. However, the situation is different for a healthy phototype IV indoor worker living in Canada who has no personal or familial history of skin cancer and takes part in no outdoor activities. Based on the current retrospective and prospective studies, physicians should individualize the sun protection advice that they give to their patients and discuss whether additional benefits can be derived from oral vitamin D supplementation. The Canadian Cancer Society issued a statement in 2007 recommending that Canadian adults should consider taking 1000 IU of vitamin D daily. This was based on evidence suggesting that vitamin D could reduce the risks of breast, colorectal, and prostate cancers.
Skin Therapy Letter. 2008;13(6):5-7. © 2008 SkinCareGuide.com
Cite this: Update on Sunscreens - Medscape - Jul 01, 2008.