By Margarita Nahapetyan
Caffeine could be helpful in protection against the most common form of skin cancer, if added to sunscreen, according to new findings.
"We have discovered what we believe to be the mechanism by which caffeine is associated with decreased skin cancer," said a lead researcher of the latest study, Dr. Paul Nghiem, an associate professor of dermatology at the University of Washington in Seattle.
Non-melanoma skin cancer, which rarely metastasize or leads to lethal outcome, is the most common form of cancer in humans, with more than a million new cases occurring every year just in the United States. Malignant melanoma is less common, with 9,500 cases per year, but is one of the deadliest cancers. Exposure to ultraviolet light is one of the primary factors that cause non-melanoma cancers. The UV rays cause DNA damage to skin cells, which later start mutating or transform into cancerous.
Few previous studies have shown that people who consume coffee or tea on a regular basis, tend to have lower incidences of non-melanoma skin cancers. One recent study that looked at more than 90,000 Caucasian women came up with the results that with each additional cup of caffeinated coffee, there was an associated 5 per cent decreased risk of developing one of these skin cancers. There were no benefits found in decaffeinated coffee so far.
For the new study, Dr. Nghiem and his colleagues examined caffeine's effect on human skin cells in a laboratory that had been damaged by ultraviolet radiation. They discovered that in cells that have been damaged by UV rays, caffeine interrupted a protein called ATR-Chk1, which caused the damaged cells to self-destruct.
"Caffeine has no effect on undamaged cells," Nghiem said, but it nearly doubles the number of damaged cells that will die off after the exposure to UV rays. "This is a biological mechanism that explains what we have been seeing for many years from the oral intake of caffeine," the scientist added.
However, Nghiem warned that people should not change their habits of beverage intake and increase the amount of coffee or tea they are used to drink in order to prevent skin cancer. "You are talking a lot of cups for a lot of years for a relatively small effect," he said. "But if you like it, it is another good reason to drink it."
The scientist has also been experimenting with applying caffeine directly to the skin. "It suppresses skin cancer development by as much as 72 per cent in mice, and human studies are moving ahead slowly," he said.
It is quite possible that topical applications of caffeine preparations might one day be used to target skin cells that are at risk, according to Nghiem. "Caffeine is both a sunscreen and it deletes damaged cells," he said. "It may well make sense to put it into a sunscreen preparation."But that application is still years away though, cautions the researcher.
The findings were published online in the February 26 edition of Journal of Investigative Dermatology.