MOTILITY
Every 90 to 120 minutes when fasted, the migrating motor complex sweeps the gut. Continuous snacking switches it off.
Roland et al., 2015
Deep dive · 1/4
The terrain: why SIBO recurs
40 to 60 % relapse at one year if you treat the overgrowth without addressing what allowed it. Five levers explain most of the terrain.
Peer-reviewed sources, informed by the clinical experience of naturopaths.
Key takeaways
ACIDITY
Long-term PPI use significantly increases SIBO risk. Reassess, do not stop abruptly.
Su et al., 2018 meta-analysis
POST-INFECTIOUS
A Campylobacter gastroenteritis can trigger anti-vinculin autoimmunity that derails motility.
Pimentel & Lembo, 2020
H₂S, 3RD GAS
Since 2022, a third gas, hydrogen sulfide, completes the H₂ / CH₄ reading of breath tests.
Singh et al., 2023
Lever 1, Motility
The migrating motor complex (MMC), the gut's housekeeper
Every 90 to 120 minutes when fasted, a contractile wave sweeps the small bowel from stomach to colon. This 'migrating motor complex' clears residual bacteria and mucus. When it fails, diabetic gastroparesis, post-gastroenteritis sequelae, hypothyroidism, scleroderma, bacteria stagnate and proliferate. It is the first mechanical cause of SIBO.
Practical consequence: spacing meals 4 to 5 hours apart with no snacks lets the MMC do its job. Continuous snacking is enemy number one of the SIBO terrain.
Lever 2, Gastric acidity
Hypochlorhydria and long-term PPIs
Gastric acid is an antimicrobial barrier. A 2018 meta-analysis (Su et al.) confirms that prolonged proton-pump inhibitor (PPI) use significantly increases SIBO risk. It is not the only factor, but it is a major one, often invisible because PPIs are prescribed for years without reassessment.
The conversation to have with your doctor is not abrupt discontinuation, rebound is possible, but reassessment: is the treatment still indicated? Is a gradual taper with mechanical measures (raising the bed, splitting meals) feasible?
Lever 3, Anatomy
Ileocecal valve and adhesions
The ileocecal valve separates the small bowel (bacteria-poor) from the colon (densely populated). An incompetent valve, post-appendectomy, abdominal surgery, ileal Crohn's, lets colonic flora rise into the small bowel. Surgical adhesions, diverticula, and blind loops also create stagnation zones where bacteria settle.
Lever 4, Post-infectious
Anti-CdtB / anti-vinculin autoimmunity
An E. coli, Campylobacter or Salmonella gastroenteritis can trigger an autoimmune reaction against vinculin, a protein in the interstitial cells of Cajal that pace the MMC. Motility becomes deregulated and the terrain primes SIBO. It is also a recognised mechanism in post-infectious IBS (Pimentel & Lembo 2020). A serological test (IBS-Smart) exists but its clinical reach remains debated.
Lever 5, Gut-brain axis
Chronic stress slows the MMC
The autonomic nervous system paces gut motility through the vagus nerve. In chronic sympathetic mode (stress, hypervigilance, poor sleep), motility slows, the stomach empties less well and the MMC fades. This is not 'psychological' in a vague sense, it is physiology. Heart coherence, regular sleep, morning light exposure and post-meal walks act as real behavioural prokinetics.
The H₂S subtype, a new piece of the puzzle
Why a 3-gas test changes the reading
Standard breath tests measure hydrogen (H₂, diarrhoeal pattern) and methane (CH₄, constipated pattern, now called IMO). A third gas signature has emerged since 2022: hydrogen sulfide (H₂S), linked to a diarrhoeal phenotype with urgency and marked discomfort (Singh et al. 2023). The 3-gas Trio-Smart test can spot an H₂S profile 'masked' by an uninformative H₂/CH₄.
To date, diagnostic thresholds and an H₂S-SIBO-specific treatment protocol are not standardised. A Trio-Smart result is read in clinical context, not alone.
This exploration is educational and does not replace medical advice, in particular a gastroenterology consultation. Terms and conditions →
Sources
- Pimentel M et al.. « ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth ». Am J Gastroenterol, 2020.
- Singh R et al.. « Methanogens and hydrogen sulfide-producing bacteria guide distinct gut microbe profiles and IBS subtypes ». Am J Physiol Gastrointest Liver Physiol, 2022.
- Singh R et al.. « Hydrogen sulfide SIBO and the 3-gas breath test (Trio-Smart) ». Clin Transl Gastroenterol, 2023.
- Pimentel M, Lembo A. « Microbiome and its role in IBS: post-infectious IBS ». Gastroenterology, 2020.
- Su T et al.. « Meta-analysis: PPI use and SIBO risk ». J Gastroenterol, 2018.
- Roland BC et al.. « Small intestinal transit time is delayed in small intestinal bacterial overgrowth ». J Clin Gastroenterol, 2015.