Gut microbiome implicated in healthy aging, longevity, study finds

Researchers from the Institute for Systems Biology in Seattle, Washington identified distinct signatures in the gut microbiome that are associated with either healthy or unhealthy aging trajectories, which in turn predict survival in a population of older individuals, according to a new study published in the journal Nature Metabolism.

The gut microbiome is an integral component of the body, but its importance in the human aging process is unclear, the researchers said.

For the study, the research team analyzed gut microbiome, phenotypic, and clinical data from over 9,000 people between the ages of 18 and 101 years old across three independent cohorts. The team focused on longitudinal data from a cohort of over 900 community-dwelling older individuals, 78-98 years old, tracking health and survival outcomes. 

The data showed that gut microbiomes became increasingly unique as individuals aged, starting in mid-to-late adulthood, which corresponded with a steady decline in the abundance of core bacterial genera that tend to be shared across humans, the researchers said. While microbiomes became increasingly unique to each individual in healthy aging, the metabolic functions the microbiomes were carrying out shared common traits.

According to the researchers, this gut uniqueness signature was highly correlated with several microbially-derived metabolites in blood plasma, including tryptophan-derived indole, which has previously been shown to extend lifespan in mice. Blood levels of metabolite phenylacetylglutamine showed the strongest association with uniqueness, and prior work has shown that this metabolite is indeed highly elevated in the blood of centenarians.

The researchers said this analysis highlights the fact that the adult gut microbiome continues to develop with advanced age in healthy individuals, but not in unhealthy ones, and that microbiome compositions associated with health in early-to-mid adulthood may not be compatible with health in late adulthood.

"This is exciting work," said Nathan Price, PhD, corresponding author of the paper and professor at the Institute for Systems Biology, in a statement, “that we think will have major clinical implications for monitoring and modifying gut microbiome health throughout a person's life.”