University of California San Francisco
Helen Diller Family Comprehensive Cancer Center

Can Sunlight Help Prevent Skin Cancer?

By Colleen Paretty, UCSF Today | March 18, 2005

Going out into the sun has become an act of war for many people. The sunscreen, hat, long sleeve -- all are worn to ward off the sun's rays and protect against photo aging and skin cancer.

But while the hazards of sun exposure are real, the sun may not be entirely the enemy some people think it is, says UCSF's Daniel D. Bikle, MD, PhD. He and fellow researchers at the San Francisco Veterans Administration Medical Center say that the vitamin D that sunlight helps the body create may help prevent a number of cancers, including skin cancer.

"While the issue remains controversial in the scientific community, a growing body of scientific evidence suggests that just a little sun a day may be beneficial in warding off at least one form of skin cancer, squamous cell carcinoma, and, perhaps, other types of skin cancer as well," says Bikle, who is also professor of medicine and dermatology at UCSF. The findings appear in the December 2004 issue of the Journal of Nutrition.

That the body needs sunlight to create vitamin D through a chemical reaction in skin cells is well established. Some epidemiologic evidence even suggests that inadequate vitamin D nutrition (which happens in part from too little sunlight exposure) is linked to colon, breast and prostate cancer. Bikle and other scientists say that sunlight's impact on vitamin D production may also help prevent some skin cancers. A form of vitamin D in the body triggers certain responses in cells that determine whether genes become active or inactive.

Read more at Colleen Paretty, UCSF Today