Being fat stops the immune system from remembering how to fight off illness, meaning that it limits the body from getting an immunity to flu.
The results in the Journal of Immunology said that fat mice were not able to develop protective influenza-specific memory T cells, generated by the body during an initial flu infection.
These cells are vital against protecting a second infection by targeting proteins common among flu viruses. Less fatty mice could develop the infection-fighting T cells and ward off the flu.
“Our work suggests that obese people should be considered at high risk for infection,” said the study’s lead author Erik Karlsson, a doctoral candidate in nutrition.
The lean mice were fed with low-fat food while the fatty mice were fed with a high-fat diet. When the mice recovered from the first bit of flu, they was infected a second time with a more lethal form of flu.
“We lost none of the lean mice, but 25 percent of obese mice died,” Karlsson says.
It builds on other research that sees fat patients struggle more against flu viruses.
The guess is that fat may restrict lung volume, with obesity causing chronic inflammation and influencing the immune response.
So next time you pick up that pie, it might give you more than indigestion.