However you feel about your body fat, you now have a new reason to appreciate it: Research suggests that molecules produced by fat cells can help fight off infections.
The study, published earlier this month in Science, examined how fat cells located just under the skin function in mice when their skin is exposed to bacteria. Researchers found in their first experiment that mice produced more fat cells in an area that had been exposed to Staphylococcus aureus bacteria. Those fat cells, in turn, produced a peptide called cathelicidin. In a second experiment, scientists looked at S. aureus infections in mice whose cells couldn't adequately produce cathelicidin. Infections in these mice were much worse, suggesting the peptide may have a protective effect against infection.
While previous research has demonstrated cathelicidin's antimicrobial properties, this is the first experiment to show that fat cells can produce the compound. This study is also notable for showing evidence of infection fighting before white blood cells reach an affected area. Though the study was conducted with mice, it likely has relevance for humans, too, as we also produce cathelicidin. And, S. aureus bacteria can trigger infections in us as well: It's the most common cause of staph infections.
It's important to note, though, that this doesn't mean that having more body fat will offer better protection against infections. The stuff you've got is probably doing the job just fine.