Diet challenge to study irritable bowel syndrome and gut microbiota
Official title: Fecal Bile Acids, Fecal Short Chain Fatty Acids and the Intestinal Microbiota in Patients With Irritable Bowel Syndrome (IBS) and Control Volunteers: Diet Challenge
Run by University of California, Los Angeles · NCT06668922 · Data updated 2026-11-12
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
| Study type | Interventional |
|---|---|
| Ages | 18 Years to 75 Years |
| Sex | All |
| Enrollment | 72 (estimated) |
| Sponsor | University of California, Los Angeles Academic / other |
| Drugs / interventions | radiation |
| Locations | 1 site (Los Angeles, California) |
| Status | Recruiting |
| Started | November 28, 2024 |
| Main results expected | December 31, 2029 |
| Study ends | December 31, 2030 |
| Registry record updated | August 12, 2026 |
| Trial ID | NCT06668922 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates include adults aged 18-65 who meet the Rome IV criteria for IBS, both diarrhea-predominant and constipation-predominant.
✕Probably not a fit
Patients with inflammatory bowel disease, celiac disease, or other significant gastrointestinal issues may not benefit from this study.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
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.
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 gone: Other studies have shown promising results in understanding the gut microbiome's role in IBS, making this approach both relevant and potentially impactful.
Who can join: the full rules
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 it's running
-
University of California, Los Angeles
Los Angeles, California, United States Recruiting
Similar studies
Other studies for the same condition or treatment. Recruiting studies are listed first.
-
Vitamin D Supplementation in Children with Irritable Bowel Syndrome
This study tests whether giving vitamin D to children with IBS and low vitamin D levels can improve their IBS symptoms compared with a placebo.
-
IBS-oriented Crohn's Disease Exclusion Diet versus Low FODMAP Diet for IBS
This study tests whether an IBS-adapted Crohn's Disease Exclusion Diet (CDED) can better help adults with IBS-D or IBS-M than the low FODMAP diet.
-
How certain FODMAPs affect IBS pain in adults
This study tests whether adding back specific FODMAP types after a low-FODMAP diet can reveal which ones drive abdominal pain in adults with IBS.
-
Gut–brain gut study in IBS with anxiety and depression
This study will compare people with IBS and mood symptoms to healthy volunteers to see if gut bacteria relate to brain function using questionnaires, stool and blood samples, and a brain MRI.
-
Pregabalin for irritable bowel syndrome in adults
A clinician-led study will test whether pregabalin helps adults with irritable bowel syndrome who meet specific symptom criteria.
-
Probiotic combination for irritable bowel syndrome
This trial will test whether a daily probiotic capsule lowers symptom severity and affects gut transit time in adults with IBS.
How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.