Study Identifies Nine Gut Bacteria Associated With Future Type 2 Diabetes Risk

What if your gut could predict diabetes years before it begins? A new study suggests the answer may lie in the microbes living inside your intestines.

A study published in Cell Reports Medicine has identified specific gut bacteria and microbial functions that may predict the future risk of type 2 diabetes (T2D) years before diagnosis. Researchers analyzed shotgun metagenomic data from 4,685 medication-naive Swedish adults who were free of diabetes at the start of the study.

Participants, with an average age of 73.9 years, were followed for a median of 5.3 years, during which 383 people (8.2%) developed T2D. Researchers found that overall gut microbial diversity was not linked to diabetes risk. Instead, certain bacterial species and their metabolic activities appeared to be more important.

Six bacterial species, including A. muciniphila, D. piger, A. communis, A. finegoldii, R. gnavus, and a member of the Lachnospiraceae family, were associated with a higher future risk of T2D. In contrast, C. catus, an Erysipelo-trichaceae bacterium, and a Clostridia species were linked to a lower risk.

The study also found that the effects of A. muciniphila depended on diet. Higher levels of the bacterium were associated with greater inflammation in people consuming low-fiber diets, while the opposite pattern was observed in those with higher fiber intake, suggesting diet may influence how gut microbes affect health.

Researchers also identified three microbial metabolic pathways linked to diabetes risk. Asparagine degradation was associated with increased risk, whereas mannose degradation and the non-oxidative pentose phosphate pathway appeared protective.

Although the findings cannot prove cause and effect, the researchers say they highlight the potential of the gut microbiome as an early marker of diabetes risk and could eventually support personalized prevention strategies based on diet and gut health.

REFERENCE: Toubon, G. et al. (2026) Gut microbiome composition and functional potential associate with incident type 2 diabetes in 4,685 adults from a Swedish prospective cohort. Cell Reports Medicine. 7. DOI: 10.1016/j.xcrm.2026.102835.