MONDAY, July 31 (Foodconsumer.org) - Regularly drinking caffeinated beverages such as coffee and tea and do physical exercise may help reduce the risk of UV-induced skin cancer, according to a new study by researchers from Rutgers - the State University of New Jersey.

Both caffeine and exercise alone promotes apoptosis of the damaged skin cells that would likely turn into cancerous cells, eventually leading to the development of skin cancer, the animal study found.

However, when the duo is used together, they exhibit a synergistic effect and effectively kill off skin cells damaged by sun’s ultraviolet-B (UVB) radiation, which would have a chance of developing into cancerous cells.

The study was conducted by Allan Conney from the Susan Lehman Cullman Laboratory for Cancer Research at Rutgers’ Ernest Mario School of Pharmacy and colleagues.   The results appear in the July 31 Proceedings of the National Academy of Sciences (PNAS).

In the study, four groups of hairless mice whose skin is vulnerable to the damage by the sun rays were assigned caffeinated water alone; exercise alone; both caffeinated water and exercise, and a placebo with neither caffeinated water nor exercise.

All the mice were exposed to UV rays from a lamp.

The amount of caffeine in the water was equivalent to the amount in one or two cups of coffee.   The exercise was running on a wheel for 3 kilometers a day.

To evaluate apoptosis or the cancer cell killing effect of caffeinated water and exercise, the researchers measured chemical markers such as caspase-3, an enzyme that is involved in killing DNA-damaged cells and p53, a tumor suppressor.

“If apoptosis takes place in a sun-damaged cell, its progress toward cancer will be aborted,” said Allan Conney, meaning that use of caffeinated water along with doing physical exercise may reduce risk of skin cancer if the observation was repeated in human trials.

“The differences between the groups in the formation of UVB-induced apoptotic cells – those cells derailed from the track leading to skin cancer – were quite dramatic,” Conney said.

The researchers found that apoptosis, programmed cell deaths that are essential for a normal cell life circle, was observed in all four groups.   Compared to the control, the caffeine drinkers showed a 95 percent increase in apoptosis, exercisers increased apoptosis by 120 percent.

However, the group who drank caffeinated water and did exercise increased apoptosis by 400 percent.   It is just unknown if this magnitude of apoptosis falls out of the normal range though.    When it comes to apoptosis, the more does not always mean the better.

Conney and colleagues attributed the enhanced protective effects of caffeine and exercise to some type of synergy between the two, whose mechanism still remains a mystery to the researchers.

The study was conducted in animals; meaning it is unknown whether the results may be duplicated in humans or if drinking caffeine-containing beverages such as coffee or tea would help prevent skin cancer.

Early studies by the same team showed that “oral administration of green tea or a caffeine solution, but not decaffeinated green tea, inhibits UVB-induced complete carcinogenesis in SKH-1 mice.”   The results were published in the Nov 7 2006 issue of Toxicology and applied pharmacology .

The link between caffeine consumption and risk of various cancers such as colon, ovary and breast cancer has been studied early.   Caffeine shows protective effects against certain cancers in animal models.

Skin cancer is the most common cancer in the United States. It’s commonly believed that excessive exposure to sunlight is the cause of the cancer.

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