The extensive, well-funded search for genetic differences in long-lived individuals has found little: small effect sizes, and only a few genetic variants that replicate in multiple studies. Will the search for gut microbiome differences characteristic of long-lived individuals do any better? This remains to be seen, as the research community is only a few studies into this exercise, and it takes more than a few studies to build a consensus. The evidence to date suggests cautiously optimism, as researchers do see differences in microbial species abundance in exceptionally old individuals versus merely old individuals. As noted here, viral diversity may also be important.
Studying 176 healthy Japanese centenarians, the researchers learned that the combination of intestinal bacteria and bacterial viruses of these people is quite unique. Among other things, the new study shows that specific viruses in the intestines can have a beneficial effect on the intestinal flora and thus on our health. "We found great biological diversity in both bacteria and bacterial viruses in the centenarians. High microbial diversity is usually associated with a healthy gut microbiome. And we expect people with a healthy gut microbiome to be better protected against aging related diseases."
Once we know what the intestinal flora of centenarians looks like, we can get closer to understanding how we can increase the life expectancy of other people. Using an algorithm designed by the researchers, they managed to map the intestinal bacteria and bacterial viruses of the centenarians.
"We have learned that if a virus pays a bacterium a visit, it may actually strengthen the bacterium. The viruses we found in the healthy Japanese centenarians contained extra genes that could boost the bacteria. We learned that they were able to boost the transformation of specific molecules in the intestines, which might serve to stabilise the intestinal flora and counteract inflammation. If you discover bacteria and viruses that have a positive effect on the human intestinal flora, the obvious next step is to find out whether only some or all of us have them. If we are able to get these bacteria and their viruses to move in with the people who do not have them, more people could benefit from them."