Inflammation tends to increase as we grow older. But this process does not begin at the same time or progress at the same rate in everyone.
New research suggests that the gut microbiome may be associated with some of these differences.
Higher inflammation appeared in some younger adults
A large 2026 population study identified several common patterns of gut microbiota.
One of them, called the Bacteroides 2 microbiome profile, was associated with higher levels of several inflammatory markers, including C-reactive protein (CRP), IL-6 and TNF-α.
What made the finding particularly interesting was when these differences appeared.
Higher levels of these inflammatory markers were already present in younger adults with the Bacteroides 2 profile.
In some cases, the difference represented decades
The researchers modeled how individual inflammatory markers changed with age across different microbiome profiles.
For several markers, people with other microbiome profiles did not reach levels comparable with those seen in young adults with the Bacteroides 2 profile until many years later.
For some inflammatory markers, the modeled difference reached approximately 37 years.
This does not mean that people with the Bacteroides 2 profile were biologically 37 years older.
The study compared age-related trajectories of specific markers. It did not measure or compare the participants’ overall biological age.
The differences extended beyond inflammation
The Bacteroides 2 profile was also associated with higher body mass index and triglycerides, lower HDL cholesterol and lower cardiorespiratory fitness.
This is important because the differences were not confined to inflammatory markers. They were accompanied by a broader pattern of less favorable metabolic and physiological measures.
The study cannot determine whether the microbiome contributed directly to these differences. Diet, lifestyle, metabolic health and other factors may influence both the microbiome and these health markers.
Why does this matter for healthy aging?
Healthy aging begins long before old age.
In this study, differences in inflammatory and metabolic markers associated with the Bacteroides 2 microbiome profile were already visible in younger adults.
Understanding why these differences appear earlier in some people could help researchers identify biological processes associated with less favorable health trajectories before age-related disease develops.
Based on Research
Eriksen C, Chatzigiannidou I, Dehli RK, et al. Gut microbiota composition outperforms chronological age in predicting systemic inflammation and incident disease risk. Nature Communications. 2026.
