The Gut-Brain-Immune Axis in Environmental Sensitivity Illnesses: Microbiome-Centered Narrative Review of Fibromyalgia Syndrome, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Multiple Chemical Sensitivity. — ME/CFS Atlas
The Gut-Brain-Immune Axis in Environmental Sensitivity Illnesses: Microbiome-Centered Narrative Review of Fibromyalgia Syndrome, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Multiple Chemical Sensitivity.
Watai, Kentaro, Taniguchi, Masami, Azuma, Kenichi · International journal of molecular sciences · 2025 · DOI
Quick Summary
This review examines how changes in gut bacteria may contribute to ME/CFS, fibromyalgia, and multiple chemical sensitivity—three conditions that share similar symptoms like fatigue, pain, and sensitivity to environmental triggers. The researchers found that people with these conditions tend to have fewer helpful bacteria and more harmful bacteria in their gut, which may affect how their immune system and brain work. The review suggests that treatments targeting the microbiome—such as probiotics or other interventions—might help, though more research is needed to confirm this.
Why It Matters
This review provides a unifying biological framework connecting gut dysbiosis to ME/CFS pathophysiology, suggesting that microbiome-targeted therapies may offer new treatment approaches for a condition lacking effective standard therapies. By highlighting shared mechanisms across multiple environmental sensitivity illnesses, it may accelerate research into microbiome interventions and inform personalized treatment strategies for ME/CFS patients.
Observed Findings
Reduced microbial diversity documented in FMS, ME/CFS, and MCS populations
Depletion of anti-inflammatory bacterial species (Faecalibacterium prausnitzii, Bifidobacterium) across all three conditions
Enrichment of pro-inflammatory Clostridium species in environmental sensitivity illnesses
Alterations in short-chain fatty acid and amino acid metabolite production linked to dysbiosis
Shared overlapping clinical features and biological mechanisms across FMS, ME/CFS, and MCS
Inferred Conclusions
Dysbiosis and gut-brain-immune axis dysfunction represent a potential unifying biological mechanism across environmental sensitivity illnesses
Microbiome-targeted interventions warrant further investigation as potential therapeutic approaches for ME/CFS and related conditions
Reduction in anti-inflammatory microbial taxa may contribute to neuroinflammation and metabolic dysfunction in these illnesses
Integrating microbial, immunological, and neurophysiological perspectives may advance understanding of ME/CFS pathophysiology
Remaining Questions
Do microbiome alterations precede ME/CFS symptom onset, or do they develop secondary to the disease process?
What This Study Does Not Prove
This narrative review does not prove that dysbiosis causes ME/CFS—it establishes association and mechanistic plausibility but cannot establish causation. The review does not demonstrate that current microbiome-targeted interventions (probiotics, FMT) are effective in ME/CFS, as controlled clinical evidence remains limited. Individual patient responses to microbiome interventions may vary significantly and require further investigation.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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