Bifidobacterium adolescentis is a Gram-positive, obligate anaerobic species within the phylum Actinobacteria and the dominant Bifidobacterium species in the adult human gut. It is a specialist degrader of resistant starch and dietary fiber, producing acetate and lactate that are cross-fed to butyrate-producing bacteria in the colon.
This species is consistently depleted in multiple disease states. In type 2 diabetes, metformin treatment has been shown to partially restore B. adolescentis abundance, suggesting the species is sensitive to the metabolic environment and may mediate some of metformin's gut-level therapeutic effects ([1], randomized controlled trial). Mendelian randomization studies have identified genetically predicted B. adolescentis abundance as inversely associated with autoimmune disease risk ([2], Mendelian randomization). The species is also depleted in multiple sclerosis, where its loss contributes to reduced short-chain fatty acid production and impaired immune regulation ([3], review).
Cross-References
- actinobacteria — parent phylum
- akkermansia muciniphila — co-depleted commensal in multiple conditions
- type 2 diabetes — primary condition of depletion
- short chain fatty acids — metabolic output