Researchers at the University of Hawaiʻi at Mānoa have found an association between gut bacteria and a molecular marker of the rate of aging. A microbiome-based model explained about 15% of the variation in this marker in a test dataset. The study was published in the journal Scientific Reports.
The researchers analyzed stool and blood samples from 123 participants aged 17 to 82. They used bacterial DNA to determine the composition of the gut microbiome and DNA methylation in blood cells to assess epigenetic markers of aging. The study also included Native Hawaiians and other Pacific Islander populations, which have been underrepresented in similar research.
The strongest association was found with DunedinPACE, a measure that estimates the rate of age-related changes rather than simply the number of years a person has lived. To investigate this relationship, the researchers developed EpiBiome machine-learning models based on the relative abundance of gut bacteria.
At the species level, the model explained approximately 15% of the variation in the marker. Adding chronological age did not improve its predictive performance. Meanwhile, models designed to predict accelerated aging based on three other epigenetic clocks showed no convincing predictive ability. Therefore, the findings apply to a specific marker and do not mean that bacteria determine 15% of human aging.
One of the most important features in the model was Bifidobacterium adolescentis, which was associated with a slower rate of aging. In contrast, Succinivibrio dextrinosolvens was associated with accelerated aging. However, these statistical associations do not make individual bacterial species universal markers of youth or old age.
The authors emphasize that the study is preliminary: the sample was relatively small, and external validation in an independent group is still needed. The data were collected at a single point in time and cannot establish whether bacteria influence aging or instead reflect differences in diet, metabolism, and health. Whether modifying the gut microbiome can help slow aging will need to be investigated separately.
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