Santosh K. Katiyar, Ph.D., and colleagues in the department of dermatology at Case Western Reserve University, reviewed several studies about green tea and reports that it may be useful in preventing and treating a variety of human skin disorders. The substances in green tea thought to protect against cancer are called polyphenols, which have antioxidant properties that can cancel out the damage caused by free radicals. Free radicals are molecules that damage cells'' DNA and as a result can begin the process of a cell turning cancerous.

Dr. Katiyar says it is better to drink green tea to benefit from its antioxidants. But he adds that it could be useful if applied topically on the skin. It may protect against damage from environmental pollutants, especially ultraviolet radiation from the sun, according to the researcher.

"Supplementation of skin care products with green tea may have a profound impact on various skin disorders in the years to come," he says.

Tea is commercially available in three forms: green tea, black tea and oolong tea. "Of the total tea production, about 78 percent is consumed as black tea, mainly in Western countries … while about 20 percent is consumed as green tea, mainly in Asian countries," the study authors write.

Green tea is made from the fresh leaves of the tea plant by steaming and drying them at high temperatures. Although skin-care products containing green tea are already available on the market, the products most likely have not been tested in clinical trials and the concentration of green tea polyphenols they contain is not uniform, according to the researchers.

"The next area of research will be to study whether the data we obtained in animal models is equally useful for human beings," Dr. Katiyar says. Experiments with human skin cells grown in laboratory dishes already has begun, but much more research needs to be done, he adds.

David Ringer, PhD, scientific program director for the American Cancer Society (ACS), agrees that there is not enough proof of benefit to recommend that people use skin care products containing green tea as a way to prevent skin cancer. "Until that proof is available, there already are proven sun safety practices that are very effective in preventing skin cancer," he says.

According to ACS guidelines, the most important ways to lower the risk of skin cancer are to avoid being outdoors in intense sunlight too long and to practice sun safety when you are outdoors, including:

• seeking shade;
• wearing clothing to protect your skin;
• using sunscreen with at least sun protection factor (SPF) 15;
• wearing sunglasses; and
• avoiding other sources of UV light (such as tanning beds and sun lamps)

Although a diet high in fruits and vegetables has been proven to lower risk of some cancers, results of studies about tea consumption have not been consistent, Dr. Ringer adds. Until research proves there is a definite benefit from tea and finds the best source of it as well as the right frequency of consumption, it should be considered an addition to – not a substitute for – a diet high in fruits and vegetables, he says.

"Until researchers have the opportunity to develop scientific evidence that assesses the risk-benefit of any plant extract, the public should remain cautious in accepting claims of health benefit," Dr. Ringer says.