Key Terms
Concise definitions for terms used throughout this guide
The following definitions are provided for quick reference. Full context for each appears in the relevant section of the guide.
Autologous FMT (Faecal Microbiota Transplantation)
A procedure using a person's own, previously banked stool sample to restore their gut microbiome — shown in controlled trials to produce faster, more complete post-antibiotic recovery than probiotic supplementation.
Gut-Brain Axis
The bidirectional communication system between the gut microbiome and the central nervous system, involving neural (vagus nerve), immune, and biochemical signalling pathways.
IBS (Irritable Bowel Syndrome)
A common, clinically diagnosed condition involving recurrent abdominal pain with altered bowel habits, in the absence of an identifiable structural abnormality. Diagnosed via a recognised symptom pattern (Rome IV criteria), not a single test.
Microbiome
The collective community of microorganisms — predominantly bacteria — living in and on the body, concentrated in the gut. Diversity of this community is generally more informative of health than raw microbial count.
Prebiotic
Dietary fibre that feeds and supports existing beneficial gut bacteria, as distinct from probiotics, which introduce new bacterial strains.
Probiotic
A supplement or food containing live bacterial strains intended to confer a health benefit. Rigorous trials find probiotics generally don't durably restructure the fecal microbiome of healthy adults, suggesting any benefit works through a different mechanism.
Vagus Nerve
The main communication channel between the gut and the brain, carrying signals directly in both directions — a core pathway of the gut-brain axis (Section 4).