A recent Rutgers University study supports the theory that caffeine can help protect against certain types of skin cancer on a molecular level.
It does this by suppressing a protein enzyme in the skin known as ATR. Lab trials conducted on mice seem to indicate that caffeine rubbed directly on the skin might be able to prevent harmful UV light from causing skin cancer.
Previous studies suggested that drinking about a cup of caffeinated coffee per day helped suppress ATR and triggered the die-off of cells harmed by UV rays.
"Although it is known that coffee drinking is associated with a decreased risk of non-melanoma skin cancer, there now needs to be studies to determine whether topical caffeine inhibits sunlight-induced skin cancer," said Allan Conney, director of the Susan Lehman Cullman Laboratory for Cancer Research.
In the recently-published study, instead of hindering ATR with caffeinated water, researchers genetically modified and weakened ATR in a group of mice. The result? Genetically modified mice suffered from 69% less tumors than their counterparts which grew slowly and were less aggressive.
However, the study also found that when both groups were dosed with chronic ultraviolet rays for an extended period of time, tumor development occurred in both the genetically modified and regular mice. According to Conney, this seems to indicate that inhibiting the ATR enzyme is most effective at the pre-cancerous stage before UV-induced skin cancers are fully formed.
The National Cancer Institute says sunlight-induced skin cancer is the most widespread cancer in the United States with upwards of 1 million cases each year.
Though many human epidemiologic studies associate caffeinated beverage consumption with substantial decreases in several different types of cancer, the how and why of coffee powered protection against the disease remains somewhat of a mystery.
"Caffeine might become a weapon in prevention because it inhibits ATR and also acts as a sunscreen and directly absorbs damaging UV light," added Conney.