In the largest such study to date, a research team from three cancer centers measured sunlight exposure in men and found that increased exposure to sunlight may decrease the risk of prostate cancer.

The researchers, led by Esther John, PhD, of the Northern California Cancer Center, found that men with high sun exposure had half the risk of prostate cancer than did men with low sun exposure. They said in men with certain gene variants, risk was reduced even further, to as much as 65%.

“We believe that sunlight helps to reduce the risk of prostate cancer because the body manufactures the active form of vitamin D from exposure to sunlight,” John said.

Previous research had shown that the prostate uses vitamin D to promote the normal growth of prostate cells and to inhibit the invasiveness and spread of prostate cancer cells to other parts of the body.

The researchers stressed that sunlight is not the only source of vitamin D, and that men should not try to reduce their risk of prostate cancer by sunbathing because that increases the risk of sun-induced skin cancer, especially melanoma.

“If future studies continue to show reductions in prostate cancer risk associated with sun exposure, increasing vitamin D intake from diet and supplements may be the safest solution to achieve adequate levels of vitamin D,” they said.

Wake Forest University Baptist Medical Center, Jun 15, 2005