Bile Acid Dysfunction
How bile acid pool composition shapes microbiome ecology and host signaling via FXR and TGR5.
Bile acids are not just lipid emulsifiers — they are antimicrobial signaling molecules whose pool composition shapes microbial ecology and host metabolism.
At a glance
Short answer
Bile acids are not just lipid emulsifiers — they are antimicrobial signaling molecules whose pool composition shapes microbial ecology and host metabolism.
Mechanistic summary
Microbiome alters 7α-dehydroxylation → secondary bile acid pool changes → FXR/TGR5 signaling shifts → altered FGF19, GLP-1, immune tone, and direct antimicrobial selection pressure → reciprocal effect on the microbiome.
Key concepts
- Bile Acid Dysfunction
- Dysbiosis as Ecological Adaptation
- The Host Capacity Model
Evidence status
Established biology. Sayin, Wahlström et al.; large bile acid–microbiome literature.
Definition
Disturbance of the size, composition (primary vs secondary; conjugated vs deconjugated), or signaling activity (FXR, TGR5) of the bile acid pool, frequently driven by impaired enterohepatic recirculation, ileal dysfunction, or microbiome shifts.
Mechanism
Microbiome alters 7α-dehydroxylation → secondary bile acid pool changes → FXR/TGR5 signaling shifts → altered FGF19, GLP-1, immune tone, and direct antimicrobial selection pressure → reciprocal effect on the microbiome.
Bile acids are not just lipid emulsifiers — they are antimicrobial signaling molecules whose pool composition shapes microbial ecology and host metabolism. How bile acid pool composition shapes microbiome ecology and host signaling via FXR and TGR5.
Frequently asked questions
- Can bile acids drive diarrhea?
- Yes. Bile acid malabsorption delivers excess bile acids to the colon, where they stimulate secretion and motility.
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Related concepts
Mechanistic intelligence
This concept is rated highly established based on 1 linked claim and 0 active contradictions.
This concept appears in 1 causal chain: Bile-acid pool failure → proximal small-bowel overgrowth.
1 recent registry update affect this concept (most recent 2026-05-11).
Recent updates
- 2026-05-11 · pathway linked · establishedBile-acid → proximal-overgrowth chain documented
Conjugated bile acid restriction of small-bowel overgrowth is now linked to bile-acid dysfunction and SIBO under the host-capacity framing.
bile-acidssibo
- Dysbiosis as Ecological AdaptationDysbiosis is best read as an ecological response to a changed host habitat — not a moral failure of the microbiome to be 'good.'
- The Host Capacity ModelThe Host Capacity Model (HCM) reframes chronic gut and post-viral illness as downstream consequences of colonocyte bioenergetic failure, not primary microbial pathology.
Educational disclaimer. This page is educational and informational only. It is not medical advice, diagnosis, or treatment. Consult a qualified clinician for personal health decisions.