When it comes to skin cancer prevention, we know the basics: stay out of tanning beds, use SPF every day and wear a hat or stay in the shade during extremely sunny days. But what if the way to steer clear of the most common type of cancer was more than skin deep?
A combination of caffeine and exercise may help to cut the risk of skin cancer caused by sun exposure, according to preliminary research in mice that was presented on Tuesday at the American Association for Cancer Research's annual meeting in Chicago.
Previous studies have found that caffeine and exercise are independently associated with lower skin cancer rates in mice that have been bred with susceptibility to the disease, but this is the first study to look at the combined effect of these influences. The researchers found that mice who benefitted from caffeinated water and an exercise wheel had a lower instance of skin cancer tumors -- and overall smaller tumors than those who had either just caffeine or exercise or neither.
Researchers exposed the skin cancer-susceptible mice to UVB radiation (the component of sun exposure that causes skin cancer) and then split the mice into four groups. A control group was given plain water and no exercise wheel, while another group also had plain water, along with an exercise wheel. The third group was given caffeinated water and no exercise wheel and the final group received both caffeinated water and an exercise wheel.
The researchers found that the fourth and final group of mice had 62 percent fewer non-melanoma skin tumors than the control group -- and among the mice in this group who had tumors, there was an 85 percent reduction in their volume by the end of the 14 weeks of treatment with exercise and caffeine. By contrast, the caffeine-only group, who did not exercise, had 27 percent fewer tumors than the control group and an overall 61 percent reduction in volume when compared to the control group. The group that received exercise but not caffeine had a 35 percent reduction in overall tumors and a 70 percent reduction in volume.
"I believe we may extrapolate these findings to humans and anticipate that we would benefit from these combination treatments as well," said lead researcher Dr Yao-Ping Lu, an associate research professor of chemical biology and director of skin cancer prevention at the Rutgers Ernest Mario School of Pharmacy in a statement.
The researchers didn't investigate why there might be a link between caffeine, exercise and skin cancer tumors, but they found an additional association between both caffeine and exercise and reduced body fat. They also noted reduced markers of inflammatory response among the mice who ingested caffeine and exercised. Some research suggests that fat promotes inflammation -- and that inflammation could be associated with skin cancer.