Certain gut bacteria may predict how fast your body ages

Biological aging does not always match the number of birthdays you have celebrated. Some people age faster at the molecular level, and others age more slowly. Finding modifiable factors behind that difference is a central goal of longevity science, and the gut microbiome is a leading candidate because it changes with daily habits.

Researchers at the University of Hawaii at Manoa, publishing in Scientific Reports, examined stool and blood samples from 123 adults across a wide range of ages. They profiled the bacteria in each participant's gut and compared them with DunedinPACE, an epigenetic biomarker built to estimate how quickly aging-related changes are accumulating in the body. Gut microbial composition was significantly associated with DunedinPACE, and microbial differences accounted for about 15% of the variation in biological aging rates.

Specific species stood out. Bifidobacterium adolescentis, a bacterium commonly found in healthy guts, was among those most strongly associated with slower biological aging. Succinivibrio dextrinosolvens showed one of the strongest associations with faster aging. Notably, the associations held independent of chronological age, which suggests the microbiome carries information about aging beyond the calendar.

The practical message is cautious but encouraging. The microbiome responds to diet, lifestyle and environment, so it may become a lever for influencing aging trajectories, and it may eventually serve as a biomarker for precision health. Fiber-rich, varied diets are already known to support beneficial bifidobacteria, but this study did not test any intervention, so no specific dietary recommendation follows from it.

Several caveats apply. The sample was small, and the design was cross-sectional, so it cannot show whether the bacteria influence aging or whether aging and its related health states reshape the microbiome. Roughly 85% of the variation in aging pace is not explained by gut bacteria. The findings need replication in larger, more diverse cohorts and, ideally, interventional trials before anyone treats particular species as targets or as probiotics for slowing aging.