Caffeine guards against certain skin cancers at the molecular level, according to a study appearing online August 15, 2011, in the Proceedings of the National Academy of Sciences (PNAS) that explains how the process likely works. Senior author Dr. Paul Nghiem, associate professor of dermatology and pathology at the University of Washington School of Medicine, and colleagues genetically modified mice so the rodents would have diminished function of a protein enzyme in their skin known as ATR. Several studies have reported that in humans, caffeine consumption in the form of tea or coffee is associated with lower incidences of non-melanoma skin cancers, although the mechanism for this is unclear. (Decaffeinated beverages have no effect.)
“This study has been 10 years in the making,” Nghiem explained, “since it is much more difficult to genetically target this protein enzyme specifically. But what it suggests is that caffeines protective effect against ultraviolet damage, which weve documented in other studies, is likely due to ATR inhibition.”
That means this guarding most likely works at the pre-cancerous stage, Nghiem said, before UV-induced skin cancers fully develop.
“In past studies, weve been able to show that caffeine decreases the incidence of skin cancer development,” Nghiem said. “In this study, we set out to determine how that works and how the body protects itself from skin cancer. We were able to show that caffeine manipulates the pathway of this protein in a live mouse by suppressing ATRs function.”
With more than a million new cases in the United States each year, non-melanoma skin cancer is the most common form of cancer in humans. The researchers suggest that topical application of caffeine could be useful in preventing such cancers, with the added benefit that it directly absorbs UV light, thus acting as a sunscreen.