How gut bacteria thrive on beer and bread

"When you have certain bacteria dominant in the gut, these microorganisms can produce molecules which have health promoting effects," says Harry Gilbert. (Credit: Dibson Hoffweiler/Flickr)

Research on how bacteria have evolved over 7,000 years to eat their way through yeast in the human gut could lead to new treatments for people suffering from autoimmune diseases.

A new study, published in the journal Nature, shows how Bacteroides thetaiotomicron (Bt) microbes in our digestive tract have learned to feast on complex carbohydrates called yeast mannans, which are a component in fermented foods like bread, beer, wine, and soy sauce.

The findings provide a better understanding of how our unique intestinal soup of bacteria—the microbiome—has the capacity to obtain nutrients from a highly varied diet. The findings also could speed up the development of prebiotic medicines, researchers say.

Good bacteria

“The ability of Bacteroides thetaiotaomicron to degrade yeast cell wall components may be of importance in fighting off yeast infections and in autoimmune diseases such as Crohn’s disease,” says Gideon Davies, a professor of chemistry at the University of York.

“People are very interested in developing dietary regimes where good bacteria are of benefit,” says Harry Gilbert, a professor at Newcastle University. “When you have certain bacteria dominant in the gut, these microorganisms can produce molecules which have health promoting effects.

“There’s a lot of interest in developing prebiotics. The more you understand about how complex glycans are degraded, the more you can think about developing sophisticated prebiotics that target the growth of specific beneficial bacteria.”

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The findings could help researchers understand how to provide nutrients to specific organisms in the microbiome, says coauthor Spencer Williams, a professor at the University of Melbourne.

Bacteroides thetaiotaomicron is an important part of our microbiota, the community of bacteria that live within us. By consuming carbohydrates that we can’t, which they convert to short-chain fatty acids that they secrete into our distal gut, these bacteria establish a symbiosis that nourishes the cells that line our gut wall and provide important immune signals that establish a healthy immune response.”

Researchers from the University of Michigan, Newcastle University, University of Georgia, University of Melbourne, University of Kansas, University of Victoria, and the US Department of Agriculture contributed to the study.

Source: University of York