Aside from the limitations it can place on everyday life and leisure, obesity is well-known to be linked with many serious health problems—diabetes, high blood pressure, cardiovascular disease, risk of stroke. What may not be so well-known is that “Obesity is related to a higher rate of infections and some types of cancer.”
So says Alfredo Halpern, Ph.D., of the University of São Paolo, Brazil, co-author of a recent research study funded by The Foundation for Research Support of the State of São Paolo. The National Cancer Institute reports that obesity is associated with higher rates of cancer of the colon, breast, kidney, and esophagus, as well as endometrial cancer.
Dr. Halpern and his colleagues sought to determine whether surgically induced weight loss would help to reduce these heightened risks by improving immune system function in severely overweight patients. Their study focused on 20 women and 8 men who had been diagnosed as morbidly obese and had undergone Roux-en-Y gastric bypass surgery.
In a Roux-en-Y gastric bypass, the stomach is reduced by placing staples or a band at the top of the stomach to create a small pouch. This is connected directly to the middle portion of the small intestine, bypassing the lower stomach and the upper small intestine (the duodenum). Much less food can be eaten and absorbed by the body, generally leading to significant weight loss. In the São Paolo study, the subjects had lost an average of 78.5 pounds within the six months following bypass surgery.
In order to track potential changes in the immune system, the research team analyzed blood samples from the subjects 6 months before their surgery, looking at the number and strength of the “natural killer” or NK cells and the production of cytokine in their systems. NK cells kill infected cells and tumor cells, and cytokine proteins also play an important role in the immune system’s ability to resist disease. The researchers found relatively low levels of NK function in their obese subject group prior to surgery.
When the same blood analysis was conducted 6 months following gastric bypass, the results were interesting. The number of NK cells was not greater; however, their activity level had dramatically increased—by nearly 79 percent—a significant rise in their potential effectiveness in combating tumor and infection cells. They also observed an enhanced response in cytokines such as interferon-gamma and interleukins 2, 12 and 18.
The researchers’ finding of sub-par activity of the NK cells and cytokines before the bypass and weight loss might well account for the extra vulnerability of obese patients to cancers and infections. Halpern suggests that bariatric surgery “may help protect against infections and cancer by improving the activity of certain immune cells.”
Dr. Halpern presented the results of the São Paolo study at the 90th Annual Meeting of The Endocrine Society in San Francisco.