Functions of the Gut Microbiota

The gut microbiota is the community of microbes that live along the digestive tract.

Dominant gut colonizers, such as members of the Bacteroidota and Bacillota phyla, ferment complex dietary polysaccharides.

This process produces short-chain fatty acids, like acetate, butyrate, and propionate, which support gut homeostasis.

Also, certain members of Bacteroidota can trigger the activation of regulatory T cells and boost the host’s defenses.

Some gut bacteria produce antimicrobial compounds, like bacteriocins, that kill harmful microbes.

Select members of Bacillota and Actinomycetota, synthesize essential vitamins such as vitamin K and certain B vitamins.

Certain gut bacteria convert cholesterol and bile acids into secondary bile acids. These metabolites act as signaling molecules that regulate lipid and glucose metabolism in the gut.

Gut bacteria also compete with pathogens like Clostridioides difficile for nutrients and space, reducing the risk of infections.