Coffee has been shown to reduce the risk of skin cancer by helping kill off damaged cells that could otherwise turn into tumours, according to a US study published on Monday.
The findings indicate that moderate caffeine drinking, or perhaps even applying coffee to the skin, could be useful in warding off non-melanoma cancer, the most commonly diagnosed of all skin cancers.
Using mice that had been genetically altered to suppress a protein enzyme called ATR, researchers showed that the mice were able to fend off cancer even when exposed to ultraviolet light.
Previous studies have suggested that drinking about a cup of caffeinated coffee per day has the effect of suppressing ATR and triggering the die-off of cells harmed by UV rays.
The altered mice eventually did develop cancer, but three weeks later than normal mice, according to the study published in the Proceedings of the National Academy of Sciences.
After 19 weeks of ultraviolet light exposure, the engineered mice showed 69 percent fewer tumours and four times fewer invasive tumours than the control group.
However, the protective effects only went so far. After 34 weeks of UV exposure, all the mice developed tumours.
“Eventually, if you treat them long enough, the mice will develop cancer so it is not 100 percent protection forever,” Allan Conney, one of the study’s authors, told AFP.
“Really, with almost any carcinogen, eventually all the animals will develop tumours,” added Conney, who is director of the Susan Lehman Cullman Laboratory for Cancer Research at Rutgers University in New Jersey.
Conney and his team were able to confirm their hypothesis that caffeine — when consumed or applied to the skin — works by inhibiting ATR.