100 years old and the microbiota of a youngster

Some say that growing old is a state of mind. However, a new study by Chinese researchers suggests that the secret to a long and healthy life is to be found in the bellies of those who live to a hundred years or more. To be more precise, the answers can be found in their gut microbiota, i.e. the microbial communities made up of billions of bacteria, viruses, fungi – including yeasts – and parasites that live in the warmth of the digestive system.

Their flora rival that of 20-44-year-olds

There’s no avoiding it: the diversity of our microbiota diminishes with age. However, centenarians are the exception to this rule, since their gut microbiota stays unusually rich for their age. Indeed, it is even richer than that of 44-65-year-olds and 66-85-year-olds. So, while centenarians (sidenote: Centenaire  live to the age of 100 or more. ) and supercentenarians (sidenote: Supercentenaire Supercentenarians live to the age of 110 or more. )  have lived for more than a hundred years, they have the microbiota of young adults.

Another peculiarity of centenarians’ microbiota is the strong presence of bacteria from the phylum Bacteroidetes (sidenote: Bacteroïdetes Bacteroidetes are one of the gut microbiota’s four major bacterial groups (phyla), together with Actinobacteria, Firmicutes, and Proteobacteria. One of the most common Bacteroidetes in the gut flora is the genus Bacteroides. Zafar H, Saier MH Jr. Gut Bacteroides species in health and disease. Gut Microbes. 2021 Jan-Dec;13(1):1-20. )  compared to seniors aged 66-85 and nonagenarians. However, these beneficial bacteria are usually only found in people under the age of 40 and from this point tend to diminish in favor of other bacteria not always beneficial to our health. At the same time, the flora of centenarians is relatively low in potentially pathogenic bacteria. More beneficial bacteria, less harmful bacteria: is this the magic potion centenarians use to keep illness at bay? Perhaps. In any case, numerous specific characteristics seem to serve as signatures for their exceptional longevity and healthy aging.

Longevity, a question of balance

One last particularity identified by the researchers was that the gut microbiota of centenarians is very balanced in terms of species distribution, with no single bacterium taking the lion’s share to the detriment of others. Rather than declining over time, this relative uniformity in the abundance of the various bacterial species – already incredible when you’ve seen a hundred years – instead seems to consolidate. It may even ensure the stability over time of centenarians’ gut flora and its continued richness in Bacteroidetes. Could this be the key to a long and healthy life?