Exercise and restricted diet reduce cancer polyps

The study suggests that a "negative energy balance" - produced by increasing the mice's energy output by use of a running wheel, while maintaining a restricted calorie intake - appeared to be the important factor in inhibiting the growth of polyps, which are the forerunners of colorectal tumors, says lead author Lisa H. Colbert, assistant professor in the UW-Madison department of kinesiology.

For the study, Colbert and her co-authors used mice with a genetic mutation that predisposed them to develop intestinal polyps.
"Our studies are relevant for humans in that these mice have a mutation in one of the same genes, APC, that is also mutated in human colon cancer," she explains. "The protective effect of exercise and lower body weight in our mice is consistent with epidemiological evidence in humans that suggests higher levels of activity and lower body weight reduces the risk of colon cancer."