Not only human, friendly bacteria also love apple: Study

The new research, published in journal BMC Microbiology, said that diet high in pectin, a component of dietary fiber in apples, increases amounts of certain bacteria that improve intestinal health. "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," said microbiologists at the University of Denmark.

"They also produce a chemical called butyrate, which is an important fuel for the cells of the intestinal wall," said co-researcher Andrea Wilcks. During the study, the team fed rats on a diet that was rich in whole apples, apple juice, puree or pomace, or put them on a control diet.

They then analysed the microbial content of the rats' digestive systems to see if eating apples had any impact on the numbers of presumed 'friendly' bacteria in the gut. "Certain bacteria are believed to be beneficial for digestive health and may influence the risk for cancer," said lead research Prof Tine Rask Licht.

The team used genetics instead of culture techniques to examine the microbiology of the intestines. "By working out the sequences of 16S rRNA, a molecule that is only found in bacteria, in the rats' intestines and matching these to known bacterial profiles of 16S rRNA, we could determine which microorganisms were abundant in each group of rats," Licht said.

Of course, further research is needed to determine whether the digestive system of humans responds to apples in the same way as rats, but these findings certainly suggest that the fruit has a well-deserved place in our 5-a-day, the team added.