The Stool Microbiome of Treated and Untreated IBS (Irritable Bowel Syndrome) Patients

NCT ID: NCT05972317

Last Updated: 2025-07-20

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 200 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-04-10
• Study Completion Date: 2026-11-30

Brief Summary

Irritable bowel syndrome (IBS) is considered the most common gastrointestinal disorder in humans, with an estimated global prevalence of 11%-20% of all humans. Alterations in the gut microbiome are at the center of IBS, and microbiome-induced volatile metabolites in response to dietary exposures is believed to drive a downstream impact on susceptible hosts, thereby driving the disease. However, the characteristics and functions of these metabolites remain unknown to date. The two main mechanisms invoking IBS development and flares include 1) an increase in luminal water content due to malabsorption of small molecules and 2) incrementation of colon gas production generated by the fermentation of small molecules by gut bacteria.Yet to date, a person-specific elucidation of the specific small molecules and bacteria driving IBS, and their downstream effects on the human gut epithelium remain unknown.

Over the past years, it became evident that dietary regimes, and their interactions with the intestinal microbiome, are at the center of IBS symptom generation and alleviation. The most widely used dietary intervention is a highly restrictive diet, the low-Fermentable Oligo-saccharides Di-saccharides Mono-saccharides And Polyols (FODMAP) diet, based on avoidance of multiple food items that contain available fermentable molecules.

The low-FODMAP diet remains an effective line of treatment for IBS patients, yet due to its complexity and unhealthy nature, it remains a last line of treatment and fails to impact the majority of IBS patients.

Conditions

Irritable Bowel Syndrome

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

Non-IBS

Participants which are not suffering from IBS symptoms.

Group Type: NO_INTERVENTION

No interventions assigned to this group

IBS -low FODMAP

individuals that are diagnosed with IBS according to Rome IV criteria

Group Type: EXPERIMENTAL

Low FODMAP dietary regimen

Intervention Type: OTHER

intervention will include a guidance by a clinical dietitian about low FODMAP diet

The FODMAP diet has three phases:

1. Elimination - Avoidance from high-FODMAP foods (2-6 weeks)

2. Reintroduction -Structured challenges of specific food groups each time (6-8 weeks).

3. Maintenance - personalized diet, according to the response in step 2.

FODMAP graduates

Individuals who have practiced a low-FODMAP diet in the past

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

Low FODMAP dietary regimen

intervention will include a guidance by a clinical dietitian about low FODMAP diet

The FODMAP diet has three phases:

1. Elimination - Avoidance from high-FODMAP foods (2-6 weeks)

2. Reintroduction -Structured challenges of specific food groups each time (6-8 weeks).

3. Maintenance - personalized diet, according to the response in step 2.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Male and Female
• Age - 18-70

Exclusion Criteria

• Consumption of antibiotics 2 months prior to the first day of the experiment.
• Consumption of probiotic supplements 1 month prior to the first day of the experiment.
• Type 1 or type 2 diabetes diagnosis.
• Pregnancy, fertility treatments, breastfeeding 3 months prior to the first day of the study.
• Chronic disease - to the discretion of the study doctor.
• Cancer and recent anticancer treatment.
• Psychiatric disorders - to the discretion of the study doctor.
• IBD (inflammatory bowel diseases).
• Alcohol or substance abuse.
• BMI > 35.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Weizmann Institute of Science

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Eran Elinav, Prof

Role: PRINCIPAL_INVESTIGATOR

Weizmann Institute of Science

Locations

Weizmann institute of science

Rehovot, Israel, Israel

Site Status: RECRUITING

Countries

Israel

Central Contacts

Yotam Cohen

Role: CONTACT

Yotam.cohen@weizmann.ac.il

+97289529173

Shimrit Eliyahu Miller

Role: CONTACT

shimrit.miller@weizmann.ac.il

Facility Contacts

Yotam Cohen

Role: primary

Other Identifiers

1914-4

Identifier Type: -

Identifier Source: org_study_id