Non-digestible compounds in apples help avert obesity-related disorders like chronic inflammation and diabetes, according to a Washington State University study.
This is considered to be the first study to assess these compounds in apples grown in the Pacific Northwest.
"We know that, in general, apples are a good source of these nondigestible compounds but there are differences in varieties," said food scientist Giuliana Noratto, the study's lead researcher in a statement. "Results from this study will help consumers to discriminate between apple varieties that can aid in the fight against obesity."
Researchers said that apples, especially the tart green Granny Smith apples, trigger the production of friendly bacteria in the colon due to the presence of non-digestible compounds in higher quantities like dietary fiber, polyphenols, and low content of available carbohydrates.
Despite its exposure to chewing, stomach acid and digestive enzymes, these compounds remain unharmed when they reach the colon. They are fermented by bacteria in the colon, which aids the growth of friendly bacteria in the gut.
In obese patients, the balance of bacterial communities in the colon is disturbed. A healthy balance of bacteria in the colon steadies metabolic processes that influence inflammation and the sensation of feeling satisfied. "What determines the balance of bacteria in our colon is the food we consume," Noratto said.
Researchers said that Granny Smith apples have nondigestible compounds more than Braeburn, Fuji, Gala, Golden Delicious, McIntosh and Red Delicious.
"The nondigestible compounds in the Granny Smith apples actually changed the proportions of fecal bacteria from obese mice to be similar to that of lean mice," Noratto said.
The finding is published in the journal Food Chemistry.
