Yeast-eating gut bacteria can help battle bowel problems and autoimmune diseases

Human gut bacteria that feast on the yeast contained in fermented foods like bread and beer provides clues to new treatments for people suffering from bowel diseases.

University of Melbourne researchers collaborating with scientists from the UK, USA Canada and Belgium have unravelled the process healthy gut bacteria use to degrade complex carbohydrates in the wall of yeast cells contained in fermented foods.

Publishing their findings in Nature, the international research team say the discovery of this process could accelerate the development of prebiotic medicines to help people suffering from bowel problems and autoimmune diseases.

Coauthor Professor Spencer Williams, School of Chemistry School of Chemistry, University of Melbourne and Bio 21 explains:

The common gut bacteria called Bacteroides thetaiotaomicron can process the carbohydrates that we can’t, we now know the mechanism of how it breakdowns the yeast cells.

This bacteria in turn use the energy released from the yeast cell components, called mannans, to produce important molecules that nourish the cells that line our gut wall, and provide immune signals that establish a healthy immune response.

The research has potential in developing sophisticated prebiotics that target the growth of specific beneficial bacteria that may assist in fighting off yeast infections, reactions to fermented foods, and in autoimmune diseases such as Crohn’s disease.

“Yeast mannans appear to be a very specific food for this particular bacterium and thus may have health promoting effects on our microbiome, the varied community of bacteria within us, by specifically stimulating the growth of beneficial bacteria like Bacteroides thetaiotaomicron,” said Professor Williams.

"Australians already consume vegemite, a yeast extract, which discards the yeast cell wall in the manufacturing process. Our work shows that perhaps we should be consuming the cell wall instead, as it is a specific nutrient for this beneficial bacterium."

Bacteroides thetaiotaomicron has now been granted Orphan Drug Designation by the FDA for Paediatric Crohn’s Disease (ThetanixTM) in the UK, paving the way for further studies.

This research provides a better understanding of how to provide nutrients to specific beneficial organisms in the human micro biome.