Study suggests gut microbes may reveal how fast the body is aging

A small study suggests that the bacteria in the gut may offer clues about how quickly the body is aging. Researchers reported that certain microbial patterns were associated with a blood-based measure of biological aging pace.

The result could help scientists better understand why people who are the same age can still age differently in health terms. It also adds to growing interest in the gut as a place where diet, daily life and human biology intersect.

Researchers at the University of Hawaiʻi at Mānoa analyzed paired stool and blood data from 123 adults. Published in Scientific Reports, the study examined links between gut bacteria and molecular signs of aging rather than testing an anti-aging treatment.

Chronological age simply marks how much time has passed since birth. Biological aging measures aim to capture something else: shifts in the body’s systems that may happen more quickly in some people and more slowly in others.

The researchers looked at chemical marks on DNA, the body’s genetic blueprint. These marks help regulate gene activity, and they can be used to build research tools that estimate certain aspects of aging.

One of those tools, called DunedinPACE, estimates the pace of biological aging. The team compared its output with the kinds of bacteria found in participants’ gut samples, using computer models to identify meaningful relationships.

The analysis found that microbial differences explained about 15% of the variation in that aging measure. The association remained informative even after accounting for simple age in years.

Some bacteria were tied to slower aging scores, while others were linked to faster ones. Bifidobacterium adolescentis was among the strongest signals connected with a slower pace, making it a candidate for further study.

The pattern was not equally strong across every aging tool the researchers tested. Several other commonly used molecular clocks did not show the same predictive signal, highlighting that different measures capture different features of aging.

The study included Native Hawaiian and Pacific Islander participants, groups that are often underrepresented in this area of research. That widens the perspective, although a sample of 123 people is still far too small to support a diagnostic test.

The findings also cannot show whether the bacteria influence aging or simply reflect other factors that affect both gut health and the body. No experiment demonstrated that adding a specific microbe, taking a supplement or changing diet slowed aging.

Researchers say the next step is to examine these links in larger studies and probe the underlying biology. For now, the gut appears to be a potentially useful window into differences in aging, not a proven way to reverse the clock.

Source: University of Hawaiʻi at Mānoa.