Exercise, caffeine may stop skin cancer

A study on mice at Rutgers University in New Jersey showed that a combination of exercise and some caffeine -- equivalent to one or two cups of coffee a day -- protected against the effects of the sun's ultraviolet-B radiation, which can lead to cancer.

The caffeine and exercise seemingly conspire to kill off precancerous cells whose DNA has been damaged by UVB-rays, the authors say.

The study was published yesterday in Proceedings of the National Academy of Sciences.

Groups of hairless mice, whose exposed skin is vulnerable to the sun, were the test subjects in experiments in which one set drank caffeinated water -- the equivalent of up to two cups of coffee for humans; another set exercised on a running wheel; and a third group both drank caffeine and ran.

A fourth group, which served as a control, neither ran nor drank caffeine.

All of the mice were then exposed to lamps that generated UVB radiation that damaged the DNA in their skin cells. The Rutgers team looked for evidence of programmed cell death, also known as apoptosis, among the four groups of UVB-treated mice.

Apoptosis is the process by which cells with badly damaged DNA destroy themselves as a natural defence against illness and infection.

Drugs that induce apoptosis are currently being investigated as a means of preventing different types of cancer, but Allan Conney, one of the authors, said that the combination of caffeine and exercise appeared to have a similar protective effect.

Compared with the UVB-exposed control animals, the caffeine drinkers showed an increase of about 95 per cent in UVB-induced apoptosis, the exercisers showed a 120 per cent increase, and the mice that were both drinking and exercising showed an increase of nearly 400 per cent.

Dr Conney said the cumulative difference seen in the caffeine-drinking runners "can likely be attributed to some kind of synergy between the two factors".

Source:www.theaustralian.news.com.au