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For Gut Microbes, Not All Types of Fibre Are Created Equal

Findings by researchers at Washington University School of Medicine demonstrates that various types of fibre beneficial to some microbes could aid in design of foods.

The work – conducted in mice colonized with human gut bacteria and using new technologies for measuring nutrient processing —is a step toward developing more nutritious foods based on a strategy of targeted enrichment of key members of gut microbial communities. The researchers identified fibers that selectively increase the abundance of beneficial microbes and tracked down the bioactive components of fibers responsible for their effects. To decipher how members of gut communities compete or cooperate with each other for these fibre ingredients, they also invented a type of artificial food particle that acts as a biosensor for monitoring nutrient processing within the intestine.

The specific components of various fibres that are used by gut bacteria and confer health benefits are generally not known. Since the human genome possesses a very limited arsenal of genes that break down dietary fibre, and many gut bacterial species are chock full of these genes, people depend on gut microbes to digest fibre.

In an effort to understand which types of fibre promote the representation of different types of beneficial microbes in the human gut, and the nature of their active ingredients, the researchers screened 34 types of fibre provided by the food company Mondelez International. Their list included fibres often discarded during food manufacturing, such as fruit and vegetable peels and grain husks.

“Microbes are master teachers,” senior author Jeffrey I. Gordon, MD said. “The microbial genes that respond to the different fibres provided an important clue as to what kinds of molecules in a given type of fibre a given community member preferred to consume.”

The researchers uncovered interactions between gut bacterial species that help explain the selective effects of fibres on Bacteroides species. Understanding these relationships is important for developing foods that are optimally processed by different microbial populations that live together in the gut, according to the researchers.

Gordon noted that nutrient-containing artificial food particles could not only be used as biosensors to define the functional capabilities of a person’s microbial community, but also could help food scientists develop methods for producing more nutritious foods containing different combinations of health-promoting bioactive fibre components. [APBN]