Beer-digesting bacteria may fight disease too

Bacteria that has evolved to help us digest the yeast that give beer and bread their bubbles could also aid in fighting off yeast infections and autoimmune diseases such as Crohn's disease, new research has found.

The findings could accelerate the development of prebiotic medicines to help people suffering from bowel problems and autoimmune diseases, the researchers noted.

Evolving over the 7,000 years that people have been eating fermented food and drink, the ability of a common gut bacterium called Bacteroides thetaiotomicron to degrade yeasts is almost exclusively found in the human gut, the findings showed.

"One of the big surprises in this study was that B. thetaiotaomicron is so specifically tuned to recognise the complex carbohydrates present in yeasts, such as those present in beer, wine and bread," said Eric Martens, assistant professor at University of Michigan Medical School.

The research unraveled the mechanism by which B. thetaiotaomicron has learned to feast upon difficult to break down complex carbohydrates called yeast mannans.

Mannans, derived from the yeast cell wall, are a component in our diet from fermented foods including bread, beer, wine and soy sauce, as well as yeasts that call the microbiome home and are in some cases thought to be harmful.

"However, these bacteria turned out to be smarter than we thought: they recognise and degrade both groups of carbohydrates, but have entirely separate strategies to do so despite the substantial chemical similarity between the host and yeast carbohydrates," Martens noted.

For the study, the researchers fed mice a diet consisting of 50 percent yeast leavened bread.

The study appeared in the journal Nature.