A new microbiome study has placed Bifidobacterium adolescentis near the center of a fascinating question: can the bacteria living in the gut tell us something about how quickly the body is aging?
The study offers an intriguing early signal—and a more specific reason to keep investigating the relationship between the gut microbiome and healthy aging.
Researchers at the University of Hawaiʻi at Mānoa analyzed paired stool and blood samples from 123 adults. They compared gut-microbiome composition with DNA methylation-based measures intended to estimate biological aging. Their most notable result was that B. adolescentis emerged as the strongest microbial predictor associated with a slower score on DunedinPACE, a measure of the pace of biological aging.
That makes B. adolescentis one of the most interesting organisms to emerge from this new line of research.
Chronological age and biological aging are not the same thing
Chronological age is simply time: the number of years since birth. Biological-aging research asks a different question. It looks for molecular patterns that may reflect how the body is changing over time.
One way researchers study those patterns is through DNA methylation. Methyl groups are small chemical tags attached to DNA. Their patterns can shift with age, environment, lifestyle, and health. Scientists use combinations of these marks to build “epigenetic clocks.”
The Hawaiʻi study examined several such clocks. Gut-microbiome composition did not meaningfully predict age acceleration measured by the traditional Horvath, Levine, or GrimAge2 clocks. The significant finding appeared specifically with DunedinPACE, which is designed to estimate the current pace of biological aging rather than accumulated biological age.
At the species level, the model explained about 15% of the variation in DunedinPACE—a meaningful early signal in an area shaped by many biological, lifestyle, and environmental factors.
Why B. adolescentis stood out
The researchers used machine-learning methods to identify which bacterial signatures contributed most strongly to the model. B. adolescentis was the dominant contributor associated with a slower DunedinPACE score. Another species, Succinivibrio dextrinosolvens, showed the strongest association in the opposite direction.
Importantly, the relationship remained informative when chronological age was added to the model. In other words, the microbial pattern was not simply another way of identifying who was older.
This result fits into a broader scientific story. B. adolescentis is a common member of the adult human gut microbiome. Large-scale microbiome analyses have identified it as one of the prevalent bifidobacterial species from adolescence through older adulthood. Earlier work has also reported lower abundance in adults over 60 compared with younger groups.
Researchers are interested in the species because its strains can interact with dietary carbohydrates and produce metabolites that influence the surrounding microbial ecosystem.
What the finding means
The researchers describe these microbial signatures as “hypothesis-generating candidates.” In practical terms, the study identifies a promising direction for further research rather than a final answer.
Because the team measured microbiome composition and biological-aging markers at the same time, the research shows an association. Future studies can now explore how B. adolescentis, diet, lifestyle, and the wider microbial community may work together.
The 123-person cohort is especially valuable because it included Native Hawaiian and Pacific Islander participants who have historically been underrepresented in microbiome and aging research. Replication in larger and more varied populations will help scientists understand how broadly the finding applies.
What earlier research adds
A 2021 study in Nature Aging found lower B. adolescentis abundance among people aged 60 and older than in younger adults. The researchers then tested supplementation in models of premature aging.
They reported changes in catalase activity and aging-related outcomes in mice, fruit flies, worms, and cultured cells. These experiments offer possible biological mechanisms and help explain why researchers continue to study the species.
These preclinical findings do not establish a human benefit, but they offer possible biological mechanisms and help researchers design more focused human studies.
A registered randomized, placebo-controlled study has been designed to evaluate B. adolescentis supplementation and aging-related measures in adults ages 45 to 65. It is an encouraging next step toward understanding whether the observational signal can translate into a meaningful human outcome.
What can you do with this information now?
This research is a useful reminder that a resilient microbiome is something we can support through consistent, everyday choices.
- Feed the ecosystem with variety. Different plant fibers and carbohydrates provide different substrates for gut microbes. Build variety gradually and according to your tolerance.
- Build supportive patterns. Diet, movement, sleep, stress, medication exposure, and environment all interact with the microbiome.
- Treat microbiome tests as context. A single stool sample is a snapshot. It is not an aging diagnosis or a complete measure of health.
- Look for strain-level identity. If you choose a probiotic, check whether the label identifies the organism beyond genus and species.
- Follow the research. Studies like this help scientists identify which organisms deserve closer attention in future human trials.
The Human Strain point of view
We believe this study is exciting for the right reason: it gives researchers a more specific question to test.
Instead of treating the microbiome as one generic wellness category, scientists can examine which species and strains are present, what functions they perform, how they interact with diet and environment, and whether changing them produces a meaningful human outcome.
Human Strain offers a focused B. adolescentis formula in a straightforward daily format. We view the Hawaiʻi study as promising research context for the species and an exciting reason to follow the science as it develops.
Explore the Human Strain B. adolescentis formula.
The bottom line
B. adolescentis was strongly associated with a slower biological-aging signal in this proof-of-concept study, making it a compelling candidate for continued research.
Replication, mechanistic work, and well-designed human intervention trials can now explore whether that association may become something actionable.
For now, B. adolescentis is a compelling microbial signal—and one worth watching closely.
This article is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Speak with a qualified health professional about medical conditions, persistent symptoms, or supplement use.
Sources
- University of Hawaiʻi System News. “Gut bacteria tied to biological aging, new UH study finds.” July 22, 2026.
- Kunihiro BP, Yamamoto BY, Juarez R, Maunakea AK. Gut microbiome signatures associate with DNA methylation-based biological aging. Scientific Reports. 2026;16:21903.
- Chen S, Chen L, Qi Y, et al. Bifidobacterium adolescentis regulates catalase activity and host metabolism and improves healthspan and lifespan in multiple species. Nature Aging. 2021;1:991–1001.
- Duranti S, et al. Ecology- and genome-based identification of the Bifidobacterium adolescentis prototype of the healthy human gut microbiota. 2024.
- ClinicalTrials.gov. Effect of Bifidobacterium adolescentis on Aging in Healthy Adults (45–65 Years). NCT05603455.
