The Role That Food and Bacteria Play in Generating Abdominal Pain

NCT07688044 | Recruiting

• 1 other identifier: 6044324
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

Irritable Bowel Syndrom (IBS) affects up to five percent of Canadians and has proven difficult to treat. Our research will explore how a type of dietary carbohydrate, called FODMAPS, contributes to chronic abdominal pain in irritable bowel syndrome (IBS). FODMAPs, are poorly digested carbohydrates and removing FODMAPs from the diet relieves abdominal pain in approximately half of IBS patients. Unfortunately, FODMAPs are contained in many foods, which makes it challenging for patients to remain on a low FODMAP diet for extended periods. Our proposed research will identify which subtypes of FODMAPs are most responsible for increasing pain and will tease apart whether the pain-causing effects of FODMAPs rely on the gut microbiota or not. To identify which specific type of FODMAP causes pain, IBS patients will adopt a low FODMAP diet and then individual FODMAP subtypes will be added back to their diet while monitoring changes to their pain. Stool samples will be collected from the participants to determine whether the composition of the gut microbiota or the chemicals that it produces are changed when symptoms are improved or exacerbated by manipulating FODMAP availability. In parallel studies, the microbiota of each IBS patient will be grown in specialized conditions to mimic the environment of the gut. These patient microbial communities will be exposed to the same FODMAP manipulations as the patients themselves experience. This will allow us to test whether the changes in gut microbiota composition and the chemicals produced that occur in IBS patients in response to FODMAP manipulations also occur when only the microbiota is exposed to these manipulations. Together, these studies will aim to optimize a dietary therapy for a common chronic pain condition and will provide novel insights into how diet affects the chemicals the gut microbiota produces that contribute to abdominal pain.

Conditions

Irritable Bowel Syndrome (IBS)

Keywords

FODMAPs; Microbiota; Neuroactive mediators; Abdominal pain; GI pain signaling

Outcome Measures

Primary Outcomes (2)

• Change in Dorsal Root Ganglion (DRG) neuron rheobase by chemostat supernatant

  DRG neurons will be incubated overnight with chemostat supernatant after steady state, low fodmap media, fodmap subtype media and glucose media. Patch clamp recordings will be made from neurons the following day the rheobase (minimum current required to elicit an action potential in a neuron) will be measured. The mean rheobase for neurons exposed to the different supernatant conditions will be compared.

  2-3 week of recording for each supernatant condition.

• Change in Dorsal Root Ganglion (DRG) neuron rheobase by fecal supernatant

  DRG neurons will be incubated overnight with fecal supernatant at baseline, after low fodmap diet, fodmap subtype challenge and glucose challenge. Patch clamp recordings will be made from neurons the following day the rheobase (minimum current required to elicit an action potential in a neuron) will be measured. The mean rheobase for neurons exposed to the different supernatant conditions will be compared.

  2-3 weeks for each supernatant condition

Secondary Outcomes (3)

• Irritable Bowel Syndrome (IBS) Symptom Severity Score

  6 weeks

• Patient-Reported Outcomes Measurement Information System Belly Pain Score

  6 weeks

• Microbial community composition

  6 weeks

Study Arms (1)

FODMAP Challenge

EXPERIMENTAL

Participants will be on a low fodmap diet (LFD) for a total of 6 weeks. After two weeks on LFD, each participant whose IBS-symptom severity score was reduced by 50 points will be deemed a responder, and will proceed to the next stage of the study. This will entail each participant remaining on the LFD while beginning 4 four-day individual challenges every 7 days consisting of 3 FODMAP subgroup challenges (galacto-oligosaccahride, fructan, and sorbitol) and 1 glucose challenge as a non-FODMAP carbohydrate control. Each challenge will comprise of a 4-day challenge with one of the three FODMAP subgroups or a glucose challenge (as a negative control) followed by a 3-day washout period with any residual symptoms resolved while remaining on the LFD prior to the next challenge.

Other: FODMAP Challenge

Interventions

FODMAP Challenge OTHER

Prior to beginning the LFD, each participant will provide a stool sample. This will be used to inoculate a continuous culture system (chemostat) as these vessels maintain fecal microbial communities under controlled anaerobic conditions. After reaching steady state in culture media with FODMAPs (7 days), the media will be switched to a low FODMAP media for 7 days. Then each vessel will be exposed to the same FODMAP subgroups challenges and glucose challenge as the participants for 3 days. At each stage (i.e., steady state, after low fodmap media, after each challenge) culture supernatant will be collected. This supernatant will be used to test its neurophysiological effects on pain sensing neurons in pre-clinical studies. In addition, participants will provide a stool sample at each stage. Fecal supernatants will be produced from these samples and the neurophysiological effects of the fecal supernatants will be tested in pre-clinical studies.

FODMAP Challenge

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 18-70 with IBS (Rome IV (now V) criteria)
• PROMIS belly pain score \>12

You may not qualify if:

• Concurrent significant organic GI pathology (i.e. celiac, IBD, etc.) as some symptoms may be related to their disease and not IBS.
• Concurrent systemic disease and/or laboratory abnormalities considered by investigators to be risky or that could interfere with data collection.
• Major gastrointestinal surgery (e.g. Roux en y, bowel resection) as symptoms may be related to previous surgery rather than IBS.
• Body mass index above 35 kg/m2 as it is unknown how mediators in the GI tract that may be involved in pain signaling in the gut are affected by obesity.
• History of active cancer in the last 5 years, other than basal cell cancer as the treatment may have impacted the GI tract.
• Pregnant or breastfeeding women.
• Active or recent participation (\< 1 month) in a clinical study.
• Use of antibiotics, probiotics, during, or one month prior to the study as may affect gut microbiota.
• Use of new medications less than 4 weeks prior to the study as may alter gut microbiota and/or IBS symptoms.
• Allergies to any of the ingredients used in the study.
• Any immune-compromising conditions as may affect GI symptoms.
• Currently being treated for eating disorder, schizophrenia, psychosis or other acute mental disorders as participating in a diet challenge study may have negative impact on these disorders.

Sponsors & Collaborators

• David Reed: lead
• Weston Family Foundation: collaborator

Study Sites (1)

Hotel Dieu Hospital

Kingston, Ontario, K7L 5G2, Canada

RECRUITING

MeSH Terms

Conditions

Irritable Bowel Syndrome; Abdominal Pain

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Signs and Symptoms, Digestive

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Associate Professor, Division of Gastroenterology, Department of Medicine, Queen's University

Study Record Dates

• First Submitted: June 30, 2026
• First Posted: July 7, 2026
• Study Start: March 16, 2026
• Primary Completion (Estimated): March 1, 2030
• Study Completion (Estimated): March 1, 2031
• Last Updated: July 15, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)