Caffeine and exercise may be protective against skin cancer caused by sun exposure, study suggests

"We found that this combination treatment can decrease sunlight-caused skin cancer formation in a mouse model," said Yao-Ping Lu, Ph.D., associate research professor of chemical biology and director of skin cancer prevention at the Rutgers Ernest Mario School of Pharmacy in Piscataway, N.J. He presented these findings at the AACR Annual Meeting 2012, held in Chicago March 31 -- April 4.

"I believe we may extrapolate these findings to humans and anticipate that we would benefit from these combination treatments as well," Lu added.

The researchers evaluated the effects of caffeine and exercise on mice at high risk for developing skin cancer. Results showed that mice that took a dose of caffeine and exercised with a running wheel experienced 62 percent fewer skin tumors. The volume of tumors also decreased by 85 percent compared with the mice that did not consume caffeine or exercise.

Positive effects were found with either caffeine or exercise alone, but to a lesser extent. Researchers observed a 27 percent reduction in tumors in caffeine-only mice and a 61 percent reduction in tumor size. In the exercise-only mice, researchers found that tumor activity decreased by 35 percent and tumor volume decreased by 70 percent.

The researchers also found that exercise and caffeine reduced weight and inflammation. They fed mice a high-fat diet of omega-6 fatty acid-rich foods and measured the volume of the parametrial fat pad (the largest fat pad in a mouse) after two weeks of exercise and/or caffeine treatment.

Mice that had caffeine and exercised had a fat pad weight decrease of 63 percent. Caffeine-only mice had a 30 percent decrease, and exercise-only mice had a 56 percent decrease. Development and size of cancer decreased as well. The link, Lu believes, is inflammation, which dropped as much as 92 percent in mice that exercised and consumed caffeine.

This research was funded by the National Institutes of Health.