A study published in Scientific Reports on July 14 found that differences in the gut microbiome accounted for approximately 15% of the variation in biological aging among participants. The findings suggest that the gut microbiome contains important biological information linked to the rate at which the body ages at the molecular level.

“This study advances our understanding of the relationship between the gut microbiome and biological aging,” said senior author Alika K. Maunakea of the UH Mānoa John A. Burns School of Medicine. “Our results show that gut microbial patterns are significantly associated with molecular measures of aging, even after accounting for chronological age. These findings open new opportunities to explore how modifiable biological systems may influence long-term health and longevity.”

The research involved 123 adults spanning a wide age range. Scientists analyzed stool and blood samples, comparing gut bacterial composition with blood-based biomarkers that estimate biological aging. Unlike chronological age, which reflects the number of years a person has lived, biological age measures the body's physiological rate of aging.

The analysis revealed that gut microbial composition was strongly associated with DunedinPACE, an advanced biomarker that estimates the pace of biological aging. Among the microbial signatures identified, Bifidobacterium adolescentis was linked to slower biological aging, whereas Succinivibrio dextrinosolvens was associated with a faster rate of aging.

Lead author Braden P. Kunihiro noted that the findings reinforce the growing role of the gut microbiome in precision health research.

“The gut microbiome is highly influenced by diet, lifestyle, environment, and other daily exposures,” Kunihiro said. “Our findings suggest that it may serve as an indicator of biological resilience and aging, potentially supporting future strategies for healthy aging and personalized wellness.”

The study also included Native Hawaiian and Pacific Islander participants, populations that have historically been underrepresented in microbiome and aging research. Co-author Ruben Juarez emphasized that the research may help explain how environmental and social influences become biologically embedded over time.

“The microbiome lies at the intersection of human biology, behavior, and environmental exposures,” Juarez said. “Research like this helps uncover potential pathways through which lived experiences and social factors shape long-term health outcomes.”

The researchers cautioned that the study identified an association between gut bacteria and biological aging but did not establish a cause-and-effect relationship. Additional research is needed to determine whether modifying the gut microbiome can directly influence the aging process.

“This represents an important first step in understanding how the gut microbiome relates to healthy aging,” Maunakea concluded. “Future studies will help clarify the underlying mechanisms and assess whether these microbial signatures can contribute to precision approaches for promoting long-term health and well-being.”

Source: https://www.hawaii.edu/news/2026/07/22/gut-bacteria-biological-aging/