Last week we wrote about a study that showed that the glycemic response from foods was a function of the microbiome, and alluded to the fact that the microbiome likely affects many aspects of metabolism. Another paper was published this week, in the journal Cell Metabolism, that describes which bacteria are responsible for some of these effects. The authors describe how Prevotella improve glucose metabolism in healthy human subjects.

The scientists gave 39 subjects white bread and barley bread for three consecutive days and measured their glucose and insulin responses to the diets. For the most part, the barley bread was associated with an improved response over white bread, but some of the individuals’ responded with a much more stark improvement than others. The scientists then measured the gut microbiomes of each individual and noted that the microbiome changed in the most responsive individuals, and this change was characterized by an increase in Prevotella (specifically Prevotella copri) and methanogenic archaea. The opposite effect was seen in the individuals that responded least to the barley bread intervention. The scientists then confirmed these results in mice. Mice that were given fecal microbiota transplants from human responders, or P. copri probiotics had improved glycemic responses to high fiber diets than control mice.

Prevotella comes up in a lot of microbiome literature as a bug seen in ‘traditional’ societies that eat a lot of fiber. This paper demonstrates that many of the genes from Prevotella are crucial to digest the complex fibers and that this may stimulate an improved glycemic response. Collectively, many papers now support the idea that Prevotella is a critical bacterium to a ‘healthy’ microbiome.