A Healthy Tan, at Last?

It’s no secret that exposure to excessive sunlight can precipitate skin cancer – melanoma, in particular. So dermatologists (and others who protect their health) keep out of the sun, wear floppy hats, and so on. But, as with many health problems, there are two sides to the story. Sunlight may actually protect against prostate cancer by encouraging the body's production of vitamin D.

Vitamin D is manufactured in the skin during exposure to the ultraviolet (UV) rays in sunlight. Lab studies showed that healthy levels of the active form of vitamin D change the nature of prostate cancer cells so that they are less likely to spread. The frequency of prostate cancer deaths among white men in different parts of the United States showed that areas with the lowest amount of UV radiation had the highest mortality rates. Thus deaths from prostate cancer were highest in the Northeast and lowest in the Southwest.

Spending at least half an hour a day in sunlight and drinking fortified milk are the best ways to get vitamin D. Taking huge doses of supplements is not the answer; they can be toxic. If you must take a supplement, the recommended daily dose of vitamin D is 400 to 800 IU.