WEDNESDAY, Jan. 20 (HealthDay News) -- Common wisdom holds apples to be a healthy snack, and a new study agrees, finding that a component of fruit called pectin boosts levels of friendly germs in the digestive system.

Microbiologists at the University of Denmark's National Food Institute tested the effect of apple consumption by feeding rats a diet of whole apples as well as apple-derived products such as apple juice and puree.

The researchers then checked the bacteria in the guts of the rats to see if consuming apples affected levels of "friendly" bacteria, which are bacteria that are beneficial for digestive health and may reduce the risk of some diseases.

The study findings were published online Jan. 20 in the journal BMC Microbiology.

"In our study we found that rats eating a diet high in pectin, a component of dietary fiber in apples, had increased amounts of certain bacteria that may improve intestinal health," study co-researcher Andrea Wilcks said in a news release from the journal's publisher.

"It seems that when apples are eaten regularly and over a prolonged period of time, these bacteria help produce short-chain fatty acids that provide ideal pH conditions for ensuring a beneficial balance of microorganisms. They also produce a chemical called butyrate, which is an important fuel for the cells of the intestinal wall," Wilcks added.

The study authors noted that more research is needed to determine whether the findings in rats apply to humans.

More information

The U.S. National Institutes of Health has details on friendly bacteria.