Higher dietary fiber intake has been associated with improved metabolic health, although relationships between specific fiber sources, metabolic biomarkers, and gut microbial profiles remain under investigation. A study published in Diabetes Care evaluated the associations between fiber intake from different food sources and type 2 diabetes (T2D) risk in three large U.S. prospective cohorts.

The analysis included 195,222 participants followed for up to 34 years, during which 18,369 incident T2D cases were documented. The study also evaluated associations between fiber intake, plasma metabolic biomarkers, metabolomic profiles linked to T2D risk, and gut microbial features associated with fiber intake.

Findings

• Higher total fiber intake was associated with lower T2DM risk (hazard ratio [HR] 0.88; 95% CI 0.82-0.94).
• Cereal fiber showed the strongest inverse association with T2DM risk (HR 0.77; 95% CI 0.73-0.82).
• Higher fruit fiber intake was also associated with lower T2DM risk (HR 0.82; 95% CI 0.78-0.87).
• Higher total, cereal, and fruit fiber intake was linked to more favorable insulinemic, lipid, inflammatory, and metabolomic profiles associated with lower T2DM risk.
• Gut microbial species including Faecalibacterium prausnitzii, Ruminococcus lactaris, and Gemmiger formicilis were associated with higher fruit fiber intake and metabolomic profiles indicating lower T2DM risk.

Higher intake of total, cereal, and fruit fiber was associated with lower long-term T2DM risk and more favorable metabolic profiles.