Sweet Tooth In Gut Bacteria Helps Keep Us Healthy
October 27, 2013

Gut Bacteria’s Sugar Attraction Could Have Beneficial Health Effects

redOrbit Staff & Wire Reports - Your Universe Online

It may not be good for your health if you have too much of a “sweet tooth,” but it’s an entirely different story when it comes to some strains of gut bacteria, according to new research appearing in Friday’s edition of the open-access, peer reviewed scientific journal PLoS ONE.

Researchers from the Institute of Food Research looked at the interaction between those bacteria, which help us digest the food that we eat and prevent pathogens from entering our systems, and mucins, a type of protein responsible for forming the layer of mucus that coats the gut lining.

Mucins have sugars associated with them, the researchers explain, and they also provide attachment sites and nutrition for some (but not all) types of bacteria. The complexity of the sugar structures in those mucins are believed to be how the human body determines which types of bacteria are allowed to set-up shop, so to speak, and which are prohibited from doing so. Experts do not yet know exactly how this phenomenon works.

However, the new study does provide insight into how bacteria and mucins interact, and how those interactions can impact a person’s overall health. In their paper, Dr. Nathalie Juge and her colleagues demonstrate that the ability to utilize mucins in the human gut actually varies between different strains of gut bacteria.

Dr. Juge’s team analyzes Ruminococcus gnavus, a species of gut bacteria that can be found in more than 90 percent of all people, including infants who are only a couples of days old. This bacterium has also been linked to inflammatory bowel disease and other gut-related health conditions, the researchers noted. They studied two different R. gnavus strains – both capable of using mucins, but only one could use the protein as its sole food source.

Comparing the genomes of the different R. gnavus strains allowed researchers to identify the gene clusters that were used to breakdown mucins, and the differences in those genes could explain the different ways in which they take advantage of the protein, the study authors said. The structure of the mucin sugar changes in different regions of the gut and over time, suggesting they could be adapted for different environments or different colonization times.

“For example, the R. gnavus strain adapted to survive solely on mucins may give it the ability to colonize the guts of newborn babies, when mucins represent the only sources of sugars for bacteria,” the institute said Friday in a statement. “In adults, the strains of bacteria that degrade mucins are the ones most likely to contact the cells underneath the mucus and so these strains are the ones most likely to influence health.”

The researchers believe that learning which bacteria strains use mucins, and the exact ways in which they do, could give medical experts new insights into what constitutes a healthy population of gut bacteria. Furthermore, it could help scientists understand how changes to that population could be associated with Crohn's disease, ulcerative colitis and other gut-related ailments.