What is already known on this topic
The gut microbiota has been linked to a myriad of health conditions, but whether it plays a role in aging remains unclear. What’s more, although several studies have revealed age-associated changes in the gut microbiota, little is known about when these changes begin and whether they could influence long-term health and survival.
What this research adds
By analyzing the gut microbiota and clinical health data of more than 9,000 people aged 18 to 101, researchers found that the gut microbiota becomes more specific to a particular person as the individual ages in a healthy way. At the same time, there is also a decline in the levels of bacteria such as Bacteroides, which are commonly found in the human gut. The researchers identified distinct microbial ‘signatures’ that are linked to healthy aging. These signatures could predict survival in a group of older individuals.
The findings suggest that microbiota changes in advanced age could contribute to health as people become older.
The gut microbiota has been linked to a myriad of human health conditions, and now researchers have found microbial ‘signatures’ that could indicate who is more likely to age in a healthy way.
The findings, published in Nature Metabolism, suggest that microbiota changes in advanced age may not simply be diagnostic of healthy aging, but they could also contribute to health as people become older, the researchers say.
Several studies have revealed age-associated changes in the gut microbiota, but little is known about when these changes begin and whether they could influence long-term health and survival.
To assess whether gut bacteria could play a role in aging, researchers led by Eric Orwoll at Oregon Health and Science University and Sean Gibbons and Nathan Price at the Institute for Systems Biology analyzed the gut microbiota and clinical health data of more than 9,000 people aged 18 to 101. For about 900 individuals aged 78 to 98, the researchers also tracked health and survival outcomes.
As people became older, the researchers observed a steady decline in the levels of bacteria such as Bacteroides, which are commonly found in the human gut. These changes began in mid-to-late adulthood. However, in less healthy individuals, core microbes continued to be present throughout life.
The microbiota of healthy individuals, but not that of less healthy ones, showed a ‘uniqueness’ signature, meaning it became increasingly unique to each individual, or increasingly divergent from that of other individuals, as people aged, the team found.
Despite this, the gut microbes found in different individuals carried out similar metabolic functions. Among the microbial metabolites found in the blood of people during healthy aging, the researchers identified one called tryptophan-derived indole, which has been shown to extend lifespan in mice. Another metabolite called phenylacetylglutamine, which is known to be elevated in the blood of centenarians, was also found in the blood of healthy older adults.
Healthier for longer
After identifying the distinct uniqueness signatures linked to healthy aging, the researchers found that these signatures could predict survival in the group of individuals aged 78 to 98.
“Interestingly, this uniqueness pattern appears to start in mid-life — 40-50 years old — and is associated with a clear blood metabolomic signature, suggesting that these microbiome changes may not simply be diagnostic of healthy aging, but that they may also contribute directly to health as we age,” says lead study author Tomasz Wilmanski.
Although more work is needed to confirm the link between the uniqueness signature and healthy aging, the study confirms previous findings that a decrease in core microbes and an increase in uniqueness is associated with healthy individuals.
Identifying microbiota features that may increase longevity and favor healthy aging could help the world’s growing older population to age better, the researchers say. What’s more, Price says, “this is exciting work that we think will have major clinical implications for monitoring and modifying gut microbiome health throughout a person’s life.”