Diet challenge to study irritable bowel syndrome and gut microbiota

Fecal Bile Acids, Fecal Short Chain Fatty Acids and the Intestinal Microbiota in Patients With Irritable Bowel Syndrome (IBS) and Control Volunteers: Diet Challenge

Not applicable Interventional University of California, Los Angeles · NCT06668922

This study is testing how a specific diet affects gut bacteria and bowel symptoms in people with irritable bowel syndrome to see if it helps them feel better.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment72 (estimated)
Ages17 Years to 65 Years
SexAll
SponsorUniversity of California, Los Angeles Academic / other
Drugs / interventionsradiation
Locations1 site (Los Angeles, California)
Trial IDNCT06668922 on ClinicalTrials.gov

What this trial studies

This study investigates the relationship between fecal bile acids, short-chain fatty acids (SCFAs), and the gut microbiota in individuals with irritable bowel syndrome (IBS). It aims to identify specific microbiome signatures in IBS subtypes (IBS-C and IBS-D) and matched controls, and to determine how these signatures correlate with fecal SCFAs and bile acids after a dietary challenge involving inulin. Participants will undergo a screening process, followed by a dietary intervention where they will record their bowel symptoms and collect stool samples for analysis.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18-65 who meet the Rome IV criteria for IBS, both diarrhea-predominant and constipation-predominant.

Not a fit: Patients with inflammatory bowel disease, celiac disease, or other significant gastrointestinal issues may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to better understanding and management of IBS symptoms through dietary interventions.

How similar studies have performed: Other studies have shown promising results in understanding the gut microbiome's role in IBS, making this approach both relevant and potentially impactful.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age 18-75
* Individuals with irritable bowel syndrome (IBS)
* Healthy volunteers (healthy controls) with no prior history of gastrointestinal (GI) disease or symptoms
* No dietary restrictions other than vegetarian

Exclusion Criteria:

* Inflammatory bowel disease, celiac disease, or certain types of abdominal cancer, as well as those with thyroid or liver issues
* Abdominal surgery or abdominal radiation within 6 months of study participation, with an exception for C-section or gallbladder removal
* Use of any prescription, over the counter, or herbal medications known to affect gastrointestinal function or study interpretation, such as opioids, inflammatory drugs or certain antidepressants, within 6 months prior to study participation for healthy volunteers, or within 2 days of study participation for participants with IBS.
* An exception will be permitted for limited use of stable low doses of antidepressants for individuals who have been taking them for a period greater than one month.
* Rescue medication such as Bisacodyl (dulcolax) to relieve severe constipation and allow for stool collection will be permitted when needed.
* Use of Ozempic and Ozempic-type medications
* Pregnant or breastfeeding women
* Antibiotic use within 3 months of study participation
* Use of prebiotics or probiotics within the 2 weeks before the study initiation
* Regular tobacco use within the past 6 months

Where this trial is running

Los Angeles, California

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Irritable Bowel Syndromeirritable bowel syndromeIBSshort-chain fatty acidsSCFAsbile acidsfecal inulinmicrobiota
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.