30 September 2014

An apple a day could keep obesity away

Apples are a good source of non-digestible compounds that may prevent disorders associated with obesity.


Scientists at Washington State University have concluded that non-digestible compounds in apples – specifically, Granny Smith apples – may help prevent disorders associated with obesity.

Fight against obesity

The study, thought to be the first to assess these compounds in apple cultivars grown in the Pacific Northwest, appears in October’s print edition of the journal Food Chemistry.

“We know that, in general, apples are a good source of these non-digestible compounds but there are differences in varieties,” said food scientist Giuliana Noratto, the study’s lead researcher. “Results from this study will help consumers to discriminate between apple varieties that can aid in the fight against obesity.”

The tart green Granny Smith apples benefit the growth of friendly bacteria in the colon due to their high content of non-digestible compounds, including dietary fibre and polyphenols, and low content of available carbohydrates.

Read: How apples keep the doctor away

Despite being subjected to chewing, stomach acid and digestive enzymes, these compounds remain intact when they reach the colon. Once there, they are fermented by bacteria in the colon, which benefits the growth of friendly bacteria in the gut.

The study showed that Granny Smith apples surpass Braeburn, Fuji, Gala, Golden Delicious, McIntosh and Red Delicious in the amount of non-digestible compounds they contain.

Balance of bacterial communities disturbed

“The non-digestible compounds in the Granny Smith apples actually changed the proportions of faecal bacteria from obese mice to be similar to that of lean mice,” Noratto said.

The discovery could help prevent some of the disorders associated with obesity such as low-grade, chronic inflammation that can lead to diabetes. The balance of bacterial communities in the colon of obese people is disturbed. This results in microbial byproducts that lead to inflammation and influence metabolic disorders associated with obesity, Noratto said.

Read: Obesity thwarts appetite regulation

“What determines the balance of bacteria in our colon is the food we consume,” she said.

Re-establishing a healthy balance of bacteria in the colon stabilizes metabolic processes that influence inflammation and the sensation of feeling satisfied, or satiety, she said.

The study was funded with an Emerging Research Issues Internal Competitive Grant from the Agricultural Research Centre at Washington State University’s College of Agricultural, Human and Natural Resource Sciences.

Read more:

How apples keep the doctor away
Is apple peel key to building muscle?
2 apples a day keeps brain OK

Image: Granny Smith apples from Shutterstock

By Sylvia Kantor, College of Agricultural, Human & Natural Resource Sciences

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