Obesity may affect the way people respond to infections by weakening the body’s immune response, new research suggests. Investigators at Boston University examined rats infected with gum infection bacteria and found that the mice of normal-weight were better able to battle the infection than obese mice.

The researchers aren’t certain why obesity has this effect on the immune system, but say it may have to do with a protein in the body that gets altered by constant exposure to food.  Similar research has been conducted on humans, and studies have shown that obese people are more likely to have gum disease than people who are not obese.

Dr. Sara G. Grossi, a scientist at the Brody School of Medicine of East Carolina University who examined the study, says that it shines light on the fact that obesity and periodontal disease are “two diseases that are easier to prevent than to treat."