title: Caecal pH is a biomarker of excessive colonic fermentation.
abstract: OBJECTIVE
  To ascertain whether caecal pH is different in patients with irritable bowel syndrome (IBS), whose primary symptoms are bloating and distension, to healthy controls.
  
  
  METHODS
  Motility and pH data were reviewed from 16 patients with Rome III defined IBS and 16 healthy controls, who had undergone a wireless motility capsule (WMC) study using a standardized protocol. Motility measures were anchored around known anatomical landmarks as identified by compartmental pH changes. Sixty-minute epochs were used to quantify antral, duodenal, ileal, caecal and distal colonic contractility. The maximum and minimum pH was measured either side of the ileo-caecal junction.
  
  
  RESULTS
  No differences were seen in motility parameters, compartmental transit times or maximal ileal pH between the two groups. Caecal pH was significantly lower in patients compared to controls (5.12 ± 0.05 vs 6.16 ± 0.15, P < 0.0001). The ileal:caecal Δchange was greater in patients than controls (-2.63 ± 0.08 vs -1.42 ± 0.11, P < 0.0001). There was a significant correlation between caecal pH and right colonic contractility (r = 0.54, P = 0.002).
  
  
  CONCLUSIONS
  Patients with bloating and distension have a lower caecal pH compared to controls. The measurement of caecal pH using the WMC provides a quantifiable biomarker of fermentation potentially identifying those patients that may preferentially benefit from antibiotic or dietary interventions.
authors.affiliation: Adam D Farmer, Sahar D Mohammed, S Mark Scott, Centre for Digestive Diseases, Blizard Institute of Cell and Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AJ, United Kingdom.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Farmer
authors.affiliation: Adam D Farmer, Sahar D Mohammed, S Mark Scott, Centre for Digestive Diseases, Blizard Institute of Cell and Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AJ, United Kingdom.
authors.forename: Sahar D
authors.initials: SD
authors.lastname: Mohammed
authors.affiliation: Adam D Farmer, Sahar D Mohammed, S Mark Scott, Centre for Digestive Diseases, Blizard Institute of Cell and Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AJ, United Kingdom.
authors.forename: George E
authors.initials: GE
authors.lastname: Dukes
authors.affiliation: Adam D Farmer, Sahar D Mohammed, S Mark Scott, Centre for Digestive Diseases, Blizard Institute of Cell and Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AJ, United Kingdom.
authors.forename: S Mark
authors.initials: SM
authors.lastname: Scott
authors.affiliation: Adam D Farmer, Sahar D Mohammed, S Mark Scott, Centre for Digestive Diseases, Blizard Institute of Cell and Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AJ, United Kingdom.
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Hobson
mesh_terms: D000328:Adult; D001419:Bacteria / Q000378:metabolism*; D053704:Capsule Endoscopy; D016022:Case-Control Studies; D002432:Cecum / Q000382:microbiology*; D005260:Female; D005285:Fermentation; D005769:Gastrointestinal Motility; D006801:Humans; D006863:Hydrogen-Ion Concentration; D043183:Irritable Bowel Syndrome / Q000382:microbiology* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D055815:Young Adult
keywords: Bloating; Caecal pH; Caecoparesis; Colonic microbiota; Fermentation