Weight Loss in Obese Patients Provides No Protection against Colon Cancer Development

Although obesity is linked to an increased risk of certain types of gastrointestinal malignancies, losing weight may not help protect against the development of liver and colon cancer, a new study suggests.

Using a mouse model, researchers found that even after weight loss, the incidence of tumors in the colon remained unchanged. The findings were published in the American Journal of Gastrointestinal and Liver Physiology.

For the study, researchers examined obese mice (obese), and obese mice that lost weight (lean), and compared both groups with a control group.

All of the mice were given a high-fat diet, while the obese and lean groups were exposed to a carcinogen. Researchers sought to determine whether or not losing weight provided protection against colon polyps or cancer.

The results of the study showed that losing weight did not provide any protection in the lean group’s colon health.

“There were no significant differences in the polyp number (adenoma), poly size, or grade of dysplasia [in the obese and lean groups],” said researchers.

Additional findings revealed that in both groups exposed to the carcinogen, there was an increase in the markers for the growth of cancer cells and liver inflammation. Furthermore, large quantities of T cells were found to be activated in the lean group, which authors stated may be related to repairing damage caused by the inflamed liver.

“Excess fat reduction did not protect mice from colon cancer progression and liver dysplastic lesion … even though these mice had improved glucose and leptin,” the researchers wrote.

The findings suggest that there could be implications in humans too, but more research is needed.

“Our results suggest that intentional body weight loss by diet manipulation does not provide any beneficial effects on colon tumorigenesis and it may in fact aggravate liver capacity of repair,” authors concluded.