The effects of UV exposure on internal cancers

Dear WDDTY:

Re your article on prostate cancer, since I wrote The Politics of Sunlight (WDDTY vol 5 no 12), I have discovered more modern research on the effects of UV exposure on internal cancers, including a study of prostate cancer.

The authors found that prostate cancer mortality in the US declines with increasing sunlight intensity. They point out that vitamin D3 is known to be effective in inhibiting the growth of tumours, and that UV is essential to the synthesis of D3 in the body. This synthesis is far more important as a source of this vitamin than the diet, except in countries like Japan, whose typical diet includes fish very rich in vitamin D. "Despite the supplementation of foods in the US, the vitamin D obtained from the diet generally is a negligible portion of the body's supply," the study concluded (Anticancer Research, 1990; 10: 1307-10).

Probably the majority of people in Europe and America are marginally D-deficient, especially older people whose ability to synthesize vitamin D decines with age. Increased UV exposure is likely to promote long-term health for most people. Jeffrey Darlington, Richmond, Surrey....