Gastrointestinal and Microbiome Dysfunction
Gastrointestinal symptoms affect the majority of ME/CFS patients, with 50–90% reporting irritable bowel syndrome (IBS)-like symptoms. The gut microbiome—the complex ecosystem of bacteria, archaea, fungi, and viruses inhabiting the intestinal tract—has emerged as a key player in ME/CFS pathophysiology, with bidirectional connections to immune function, metabolism, and the central nervous system.
GI dysmotility is one component of the “Septad” framework of frequently co-occurring conditions in ME/CFS (Section Prospective Phenotyping as Harm Reduction). This chapter examines microbiome alterations, intestinal permeability, motility disorders, and their connections to systemic symptoms.
For patients: read the treatment approaches and dietary sections (SIBO treatment, low-FODMAP, probiotics) for actionable GI management, the gut-brain-axis section to understand brain fog and mood links, and the intestinal-permeability (“leaky gut”) section if dietary-sensitivity triggers are relevant.
For caregivers: read the GI-dysfunction and treatment sections to support dietary and motility management. The microbiome molecular sections can be skimmed.
For clinicians: read the SIBO, intestinal-permeability, and treatment sections for diagnostic testing (breath tests) and management decisions. The probiotics section carries a strain-specificity caution.
For researchers: read the multi-omic integration and butyrate-mechanism sections, plus the gut-brain axis. These cross-link to Chapter Integrative Models and Multi-System Pathophysiology.