Exclude or Expose in Irritable Bowel Syndrome: What Works for Whom and How?

NCT ID: NCT06940596

Last Updated: 2025-07-10

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 200 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-05-22
• Study Completion Date: 2027-07-31

Brief Summary

This research project will assess how two treatments for irritable bowel syndrome (one dietary and one behavioral) work and for whom. This will be done by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). Investigators will also assess how the diet and behavioral treatments affect IBS symptoms during treatment. Participants will be randomized to either: i. A FODMAP diet online program that focuses on modifying the consumption of foods high or moderate in fermentable carbohydrates (FODMAPS) to manage IBS symptoms. or, ii. An Exposure-based Cognitive Behavioral Therapy (E-CBT) online program for IBS that focuses on changing symptom-related behaviors which are known to worsen IBS symptoms.

Detailed Description

This research uses a randomized controlled trial to investigate the treatment of irritable bowel syndrome (IBS). A range of treatments for IBS are available, but each work for only a portion of patients, and it is unclear why. This research project will assess how two treatments (one dietary and one behavioral) work and for whom. Investigators will do this by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). This project will also assess how the diet and behavioral treatments affect IBS symptoms during treatment. Participants will be randomized to either: i. A FODMAP diet online program that focuses on modifying the consumption of foods high or moderate in fermentable carbohydrates (FODMAPS) to manage IBS symptoms. This treatment involves 3-phases: FODMAP restriction (phase 1), FODMAP re-introduction (phase 2), and FODMAP personalization (phase 3), or, ii. An Exposure-based Cognitive Behavioral Therapy (E-CBT) online program for IBS that focuses on symptom-related behaviors such as avoidance of activities and foods, excessive toilet visits, and behaviors to control symptoms which are known to worsen IBS symptoms. E-CBT uses daily self-observation and exposure exercises to change these behaviors to relieve IBS symptoms. Investigators believe that both treatments, FODMAP diet and E-CBT, will lead to an improvement in IBS gastrointestinal symptoms. Primary moderators and mediators to be assessed include gastrointestinal symptom anxiety, food avoidance behaviour and FODMAP intake.

Conditions

Irritable Bowel Syndrome (IBS); Intestinal Diseases; Gastrointestinal Disease

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

FODMAP Diet

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) Diet is a 12-week online intervention with dietitian support.

Group Type: EXPERIMENTAL

FODMAP Diet

Intervention Type: OTHER

The intervention is an online diet program. The diet is the low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet. It is a 3-phase diet which involves: 1.Phase 1 FODMAP restriction: restrict foods high or moderate in FODMAPs and swap these for low FODMAP alternatives; 2. Phase 2 FODMAP reintroduction: continue to follow a low FODMAP diet and complete a series of food challenges to understand which foods and FODMAPs are tolerated and which trigger symptoms; 3. Phase 3 FODMAP personalization: include well-tolerated foods and FODMAPs back into the diet, and restrict poorly tolerated foods and FODMAPs to a level needed to maintain symptom relief. The online FODMAP program is a self-directed diet program with support from an online clinician (Accredited Practicing Dietitian \[APD\]). The content is delivered over 12 weeks. After each module participants will complete homework activities and questions and submit them to the dietitian for feedback.

Exposure-based Cognitive Behavioral Therapy (E-CBT)

Exposure-based Cognitive Behavioral Therapy is a 12-week online intervention with psychologist support.

Group Type: EXPERIMENTAL

Exposure-based Cognitive Behavioral Therapy

Intervention Type: BEHAVIORAL

The intervention is an online behavioral therapy program. The behavioral therapy is Exposure-based Cognitive Behavioral Therapy (E-CBT) Program. The E-CBT program is organised into six steps to be completed over 12 weekly modules with support from an online clinician (Psychologist). The first step contains a rationale for the treatment and instructions on self-observation. Steps 2, 3 and 4 contain a presentation of a psychological model of IBS and continued self-observation exercises. The fifth step covers exposure exercises, divided into three categories; (1) exercises that provoke symptoms, (2) abolishment of behaviors that serve to control symptoms, (3) exposure to situations where symptoms were unwanted. The final step (Step 6) includes how to handle relapses into avoidance behaviors and how to maintain a widened behavioral repertoire. After each module participants will be directed to complete homework activities and questions and submit them to the psychologist for feedback.

Interventions

FODMAP Diet

The intervention is an online diet program. The diet is the low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet. It is a 3-phase diet which involves: 1.Phase 1 FODMAP restriction: restrict foods high or moderate in FODMAPs and swap these for low FODMAP alternatives; 2. Phase 2 FODMAP reintroduction: continue to follow a low FODMAP diet and complete a series of food challenges to understand which foods and FODMAPs are tolerated and which trigger symptoms; 3. Phase 3 FODMAP personalization: include well-tolerated foods and FODMAPs back into the diet, and restrict poorly tolerated foods and FODMAPs to a level needed to maintain symptom relief. The online FODMAP program is a self-directed diet program with support from an online clinician (Accredited Practicing Dietitian \[APD\]). The content is delivered over 12 weeks. After each module participants will complete homework activities and questions and submit them to the dietitian for feedback.

Intervention Type: OTHER

Exposure-based Cognitive Behavioral Therapy

The intervention is an online behavioral therapy program. The behavioral therapy is Exposure-based Cognitive Behavioral Therapy (E-CBT) Program. The E-CBT program is organised into six steps to be completed over 12 weekly modules with support from an online clinician (Psychologist). The first step contains a rationale for the treatment and instructions on self-observation. Steps 2, 3 and 4 contain a presentation of a psychological model of IBS and continued self-observation exercises. The fifth step covers exposure exercises, divided into three categories; (1) exercises that provoke symptoms, (2) abolishment of behaviors that serve to control symptoms, (3) exposure to situations where symptoms were unwanted. The final step (Step 6) includes how to handle relapses into avoidance behaviors and how to maintain a widened behavioral repertoire. After each module participants will be directed to complete homework activities and questions and submit them to the psychologist for feedback.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Living in Australia or the United States
• Aged 18 years or older
• Body Mass Index (BMI) [Equation]18.5kg/m2 and [Equation] 34.9kg/m2
• Diagnosed with IBS by a General Practitioner, Family Physician, or Gastroenterologist, or Advanced Specialist Dietitian
• Currently fulfill Rome IV criteria for IBS
• Symptomatic at the time of recruitment (IBS-SSS > 175)
• Access to a computer and internet
• Sufficient English language and computer skills to complete a text-based online treatment
• Willing to make dietary or behavioral changes in line with the allocated treatment program
• Ability to provide informed consent

Exclusion Criteria

• Presence or known history of other GI disease (e.g. coeliac disease, Inflammatory Bowel Disease) or history of gastrointestinal cancer
• History of major gastrointestinal surgery (not appendectomy, cholecystectomy or hemorrhoidectomy)
• Individuals who report alarm symptoms (e.g., blood in stool, recent unexplained/unintentional weight loss >5% body weight, a recent change in bowel habits if >50 years, family history of gastrointestinal cancer or gastrointestinal diseases, large volumes of diarrhea occurring at night, fever associated with gut symptoms, recurrent vomiting, persistent unexplained iron deficiency) will be excluded if appropriate medical investigations have not been conducted, unless written medical approval is provided from a general practitioner, family physical, or gastroenterologist.
• Diagnosis of major disease that could explain current gastrointestinal symptoms such as severe diabetic, cardiac, liver, neurological, neuropathy disease
• History or current diagnosis of psychotic disorder or bipolar disorder
• Current diagnosis of substance abuse disorder or major depressive disorder or active suicidal ideation
• History or current diagnosis of an eating disorder
• Current enteral/parenteral feeding or use of supplemental feeds (e.g. Ensure)
• Pregnant or lactating or planning to become pregnant during the 12-week intervention period
• Commenced or change in dose of antibiotics and medications that potentially affect the gastrointestinal transit (e.g. anti-diarrheals and laxatives) in the 3 months preceding study commencement.
• Commenced taking or changed dose of probiotics, prebiotics, fibre supplements and digestive enzymes in the 3 months preceding study commencement
• Commenced or change dose in psychotropic medication in the 3 months preceding study commencement
• Are currently undertaking behavioral therapy for IBS (including cognitive behavioral therapy, CBT), or have undertaken clinician-delivered behavioral therapy for the treatment of IBS
• Are currently undertaking or have undertaken a dietitian-prescribed and delivered restrictive diet for IBS (e.g., FODMAP diet).

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Monash University

OTHER

Sponsor Role: collaborator

University of Melbourne

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Associate Professor Jessica Biesiekierski

Role: PRINCIPAL_INVESTIGATOR

University of Melbourne

Locations

University of Melbourne

Melbourne, Victoria, Australia

Site Status: RECRUITING

Countries

Australia

Central Contacts

Jessica Biesiekierski, A/Prof

Role: CONTACT

jessica.biesiekierski@unimelb.edu.au

+61 499 272 673

Jacqueline L Anderson, APD

Role: CONTACT

jacquia@student.unimelb.edu.au

Facility Contacts

Jessica Biesiekierski

Role: primary

References

Biesiekierski JR, Manning LP, Murray HB, Vlaeyen JWS, Ljotsson B, Van Oudenhove L. Review article: exclude or expose? The paradox of conceptually opposite treatments for irritable bowel syndrome. Aliment Pharmacol Ther. 2022 Aug;56(4):592-605. doi: 10.1111/apt.17111. Epub 2022 Jul 1.

Reference Type: BACKGROUND

PMID: 35775328 (View on PubMed)

Other Identifiers

2024

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

APP2025943

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

CT31293

Identifier Type: -

Identifier Source: org_study_id