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Diet Challenge Study for Irritable Bowel Syndrome (IBS)

This study is looking at how your gut (gastrointestinal) microbiome, which are the tiny organisms living in your intestines, relates to Irritable Bowel Syndrome (IBS) symptoms. Researchers want to see if changes in these organisms are connected to certain substances in your stool called short-chain fatty acids (SCFAs) and bile acids. You could join if you are between 18 and 75 years old and have IBS, or if you are a healthy volunteer without a history of gut problems. The study involves a dietary challenge where you will consume inulin, a dietary supplement, to help understand how your body ferments fiber. The main goal is to measure your fecal bile acids and short-chain fatty acids 48 hours after this challenge. The study is currently recruiting 72 participants.

Study design
This is an interventional study involving 72 participants, including individuals with IBS and healthy volunteers.
What's involved
You will have a screening visit, which includes a physical exam and medical history. You will also receive a take-home meal, a stool collection kit, and instructions for a low-fiber, high-fat diet for three days at home.
Compensation
Not stated in the trial record.
Follow-up
Your fecal bile acids and short-chain fatty acids will be measured 48 hours after the dietary challenge.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06668922

Irritable Bowel Syndrome and Control Volunteers: Diet Challenge

Recruiting
NAAges 18–75InterventionalDiagnostic
University of California, Los Angeles
~72 participants
Updated 2026-08-12 on ClinicalTrials.gov
What's tested:Inulin

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Total fecal bile acids
Measured over 48 hours
+4 more outcomes measured

Conditions

Irritable Bowel Syndrome (IBS)

Explore related trials

HealthyIrritable Bowel Syndrome

Where it's being run

1 sites across 1 states
California1

Who to contact

Ren Cutrer
[email protected]
(310) 794-9507
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

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

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

What this trial measures

  • Total fecal bile acids48 hours

    Stool samples will be collected over 2 days for measurement of fecal bile acids (µmol/48h) by high performance liquid chromatography-mass spectometry.

  • Total fecal short chain fatty acids48 hours

    Stool samples will be collected for measurement of measurement of short chain fatty acids (µg/mg) by liquid chromatography-mass spectrometry

  • Individual fecal short chain fatty acids48 hours

    Stool samples will be collected for measurement of measurement of short chain fatty acids (µg/mg) by liquid chromatography-mass spectrometry

  • Fecal microbial population48 hours

    Stool samples will be be collected from participants for nucleic acid extraction, 16S allele PCR and sequencing to measure microbial communities and profiles of specimens

  • Fecal inulin48 hours

    Fecal inulin content will be measured using short acid hydrolysis and high-performance liquid chromatography