Obese people find it harder to fight infections due to a weakened immune system, suggests a new study from Boston University researchers. In experiments carried out by scientists, mice were infected with the bacteria that cause gingivitis. The results showed that obese mice had less ability to fight off the gum infection than their normal-weight counterparts.
For years, we have had difficulty understanding why obese people have difficulty clearing an infection," said researcher Dr. Salomon Amar
In the study, Amar's team tied silk threads infected with the bacteria around the molars of obese and normal-weight mice. They then compared the animals' responses to infection, by measuring both the amount of bone loss and the growth of the bacteria around their teeth. The researchers found that the obese mice had a compromised immune response to the bacteria, which made the animals more susceptible to the infection.
Amar's group also looked at the animals' white blood cells, which are the main line of defence against infection. The white cells of obese mice had lower levels of an important signaling molecule and some of the genes that fight inflammation were altered, the researchers found.
The same result is seen in humans, Amar added. Various studies of obese people have shown they are more likely to have gum disease than people with a normal body mass index. The disease is caused by bacteria, which causes inflammation and destruction of the bone underlying teeth.
Amar thinks that obese people need to be treated differently to help them fight infections. "We need to be more aggressive in the use of targeted antibiotics in infections among obese people," he said. "Also, we need to boost the immune response."