Life expectancy has been steadily increasing for many years and has more than doubled in the last two centuries. Upward lifespan trends are widespread but they are not a given. Something is not yet known and researchers do their work. A new study from Japan found people who live to age 100 and beyond may have special gut bacteria that help ward off infections. In the new study, the researchers examined the gut microbiota of 160 centenarians, who were, on average, 107 years old. They found that centenarians had a distinct “signature” of gut microbes, with significantly higher levels of so-called secondary bile acids called isoallolithocholic acid (isoalloLCA). Screened gut bacterial strains from a 110-year-old who had particularly high levels of secondary bile acids and found that bacteria belonging to a family called Odoribacteraceae. IsoalloLCA was found to have potent antimicrobial properties, meaning it could inhibit the growth of “bad” bacteria in the gut.
In experiments in lab dishes and in mice, the authors found that isoalloLCA slowed the growth of a bacterium that causes severe diarrhea and inflammation of the colon. If these bile-acid-producing bacteria will prove to contribute to a healthy gut, they might one day be used as a probiotic to improve human health. It’s unclear how centenarians come to acquire these beneficial bacteria, but both genetics and diet could play a role in shaping the composition of people’s gut microbiota. Future studies could further probe the link between these bacteria and longevity.