Gut bacteria selectively promoted by dietary fibers alleviate type 2 diabetes

TLDR

Gut microbiota produce short‑chain fatty acids from carbohydrate fermentation, and reduced SCFA production is linked to type 2 diabetes. The study aimed to demonstrate that dietary fibers selectively promote beneficial SCFA‑producing strains and that restoring these strains could offer a novel ecological strategy for managing type 2 diabetes. A randomized clinical trial using isoenergetic diets and fecal shotgun metagenomics assessed changes in SCFA‑producing bacterial populations in type 2 diabetes patients. Higher diversity and abundance of fiber‑promoted SCFA producers were associated with greater HbA1c improvement, partly through increased GLP‑1, and with reduced production of indole and hydrogen sulfide.

Abstract

The gut microbiota benefits humans via short-chain fatty acid (SCFA) production from carbohydrate fermentation, and deficiency in SCFA production is associated with type 2 diabetes mellitus (T2DM). We conducted a randomized clinical study of specifically designed isoenergetic diets, together with fecal shotgun metagenomics, to show that a select group of SCFA-producing strains was promoted by dietary fibers and that most other potential producers were either diminished or unchanged in patients with T2DM. When the fiber-promoted SCFA producers were present in greater diversity and abundance, participants had better improvement in hemoglobin A1c levels, partly via increased glucagon-like peptide-1 production. Promotion of these positive responders diminished producers of metabolically detrimental compounds such as indole and hydrogen sulfide. Targeted restoration of these SCFA producers may present a novel ecological approach for managing T2DM.