Now, customised gut bacteria for better tummy

Could tailored-to-order gut microbes improve intestinal health? Scientists have shown how these bacteria could help digest dietary fibre from fruits and vegetables, a finding that could be used to improve digestion after an illness.

Researchers at the University of British Columbia, Canada, have discovered the genetic machinery that turns a common gut bacterium into the Swiss Army knife of the digestive tract -- helping us metabolise a main component of dietary fibre from the cell walls of fruit and vegetables.

The findings illuminate the specialised role played by key members of the vast microbial community living in the human gut, and could inform the development of tailored microbiota (formerly called gut flora) transplants to improve intestinal health after antibiotic use or illness.

The research is published in the journal Nature.

"While they are vital to our diet, the long chains of natural polymeric carbohydrates that make up dietary fibre are impossible for humans to digest without the aid of our resident bacteria," says UBC professor Harry Brumer, who works with the university's Michael Smith Laboratories and Department of Chemistry, and senior author of the study.

"This newly discovered sequence of genes enables Bacteroides ovatus to chop up xyloglucan, a major type of dietary fibre found in many vegetables -- from lettuce leaves to tomatoes. B. ovatus and its complex system of enzymes provide a crucial part of our digestive toolkit."

About 92 percent of the population harbours bacteria with a variant of the gene sequence, according to the researchers' survey of genome data from 250 adult humans.

"The next question is whether other groups in the consortium of gut bacteria work in concert with, or in competition with, Bacteroides ovatus to target these, and other, complex carbohydrates," Brumer said.