A recent study finds that combining exercise and caffeine can reduce the risk of skin cancer in mice. The finding seems counterintuitive, but the researchers say the beneficial effect may ultimately have to do with weight loss.
For the study, researchers at the Ernest Mario School of Pharmacy at Rutgers University in New Jersey gave 160 mice low doses of UV light once a day, five days a week, for 20 weeks. The goal was to mimic everyday human exposure to UV radiation. They then monitored the animals’ skin-cancer development and found that mice that were given a dose of caffeine and ran on a running wheel had 62% fewer skin tumors than mice that didn’t exercise or consume caffeine. Their tumors were also 85% smaller.
Separately, caffeine and exercise also had cancer-preventing benefits, but to a lesser extent. The caffeine-only mice had 27% fewer tumors and a 61% reduction in tumor size, compared with control mice. In exercise-only mice, the researchers found a 35% decrease in tumor development and a 70% decrease in size.
Previous studies by the researchers, led by Yaoping Lu, an associate research professor of chemical biology, also found that caffeine intake and exercise separately lowered the risk of sun-related skin cancer in mice. Why? Both caffeine and exercise trigger weight loss — after two weeks of exercise and caffeine consumption, the mice had lost 63% of their fat, significantly more than the exercise-only, caffeine-only or control groups — which in turn helps inhibit skin cancer, Lu says. There are a few reasons for this, one being that fatty cells block apoptosis, the body’s natural way of ridding itself of damaged cells.
“The mice move more with caffeine. The common mechanism we see is that both [exercise and caffeine] decrease tissue fat. Both moderately prevent skin cancer,” says Lu, explaining that the current study was designed to test the effect of both factors together.
The researchers discovered an extra perk: caffeine consumption and exercise also reduced inflammation in mice by 92%. In humans, inflammation is associated with a variety of chronic illnesses, including heart disease, Alzheimer’s, cancer and asthma.
But that doesn’t mean you should start chugging Red Bulls before hitting the gym — at least not if cancer prevention is your goal. The preliminary findings are only in mice, and according to Lu, there are many other biological mechanisms that influence the development of skin cancer — and other cancers. Decreasing body fat is but one.
But, generally speaking, weight loss is becoming an increasingly important goal for cancer prevention. A recent study by the Centers for Disease Control and Prevention found that while U.S. cancer rates are on the decline overall, certain obesity-related cancers are rising. “Overall, a healthy lifestyle plays an important role in all cancer development,” says Lu.
The current findings were presented Tuesday at the American Association for Cancer Research Annual Meeting in Chicago.