Sunbathing, considered risky by skin cancer experts, may actually reduce the risk of breast and other cancers, new research has found.

Some women who had higher sun exposure had their risk of advanced breast cancer reduced by almost half, according to the scientific study.

The researchers from Stanford University, who report their findings in the American Journal of Epidemiology this week, said: "This study supports the idea that sunlight exposure reduces risk of advanced breast cancer among women with light skin pigmentation.''

The Stanford cancer specialists measured 4,000 women aged 35 to 79, half of them diagnosed with breast cancer, for the effects of long-term sun exposure.

Sun exposure may also protect against a number of other cancers, according to a second research team who studied more than four million people in 11 countries, including 416,000 who had been diagnosed with skin cancer.

These results, reported in the European Journal of Cancer, show that the risk of internal cancers after skin cancers was lower among people living in sunny countries.

The researchers said: "Vitamin D production in the skin seems to decrease the risk of several solid cancers, especially stomach, colo-rectal, liver and gall- bladder, pancreas, lung, female breast, prostate, bladder and kidney cancers."

Sunlight plays a vital role in the production of beneficial vitamin D in the body. Although food provides some vitamin D, up to 90 per cent comes from exposure to sunlight.