Patient Investigations

NOTE: This trial has now ended. Results to follow.

We are delighted to announce that The Functional Gut Clinic will shortly be embarking on a novel Clinical Trial to look at the relationship between colonic pH and symptoms in IBS patients. Our previously published work (Caecal pH in IBS pdf) using the Wireless Motility Capsule (SmartPill) has shown that the proximal colonic pH is lower in IBS patients with bloating, distension and an alternating bowel habit when compared to healthy controls.

This image shows a typical SmartPill trace with pressure in red, temperature in blue and pH in green. This particular tracing shows a stable pH in the ileum followed by a sharp drop as the capsule moves into the caecum. This pH drop is due to bacterial fermentation of undigested food. The capsule unusually moves back into the Ileum in this patient who was subsequently shown to have Small intestinal Bacterial Overgrowth (SIBO).



The low pH is due to excessive fermentation of (predominantly) carbohydrates by the colonic microbiota, and the subsequent over production of short chain fatty acids (SCFA). SCFA’s then affect the motility and sensitivity within this region and along with excessive gas production this leads to IBS symptoms.

We now wish to examine whether altering diet (using a low FODMAP approach) can normalise the colonic pH and whether this correlates with an improvement in symptoms in patients with IBS and an alternating bowel habit (IBS-A). 

In addition, we have shown that in constipation patients, the colonic pH is higher than healthy controls and we will see if this pH profiles normalises in patients that are taking a prokinteic (linaclotide).

This is an investigator led study designed by Dr Anthony Hobson and Dr Adam Farmer which was fortunate enough to win a European wide grant competition sponsored by Almirall. We are looking to recruit 32 IBS patients with IBS-A and 16 with constipation predominant IBS (IBS-C).

Patient that are successfully enrolled into the study will have their whole gut motility, pH and transit assessed as well as have a hydrogen and methane lactulose breath test prior to and following the randomised intervention (Low FODMAP v’s Control diet in IBS-A, Linaclotide only in IBS-C). After 28-days, all tests will be repeated and a formal report generated for the referring consultant / physician. We will also be using the new IBSchek, blood test; a Commonwealth Diagnostics International, Inc (CDI) product, to see what proportion of our IBS cohort test positive for post gastro-intestinal infection antibodies (IBSChek official website).

NOTE: This trial has now ended. Results to follow. 

Kind regards,

Dr Anthony Hobson and Dr Adam Farmer (2015)