Fecal Bile Acids, Fecal Short Chain Fatty Acids and the Intestinal Microbiota in Patients With Irritable Bowel Syndrome (IBS) and Control Volunteers: Diet Challenge
University of California, Los Angeles
Summary
The study will investigate the relationship between fecal bile acids, short-chain fatty acids (SCFAs), and the gut microbiota in irritable bowel syndrome (IBS). The central hypothesis of this study is that specific shifts in the GI microbiome composition correlate with altered colonic SCFAs and BAs and contribute to IBS symptoms. Primary aims include: (a) identifying GI microbiome signatures in IBS subtypes (IBS-C and IBS-D) and matched controls, and test if microbiome signatures in these groups correlate with fecal SCFAs and bacterial fermentation of an indigestible carbohydrate (inulin) after a dietary challenge (fecal inulin), and (b) determining if GI microbiome signatures in IBS subtypes and controls correlate with fecal BAs or markers of SCFA production (fecal SCFAs or inulin) and test if BAs correlate with fecal SCFAs or inulin. The target population is adults ages 18-65 years meeting Rome IV criteria for IBS (both diarrhea- and constipation-predominant, IBS-D and IBS-C) and asymptomatic controls. Primary outcomes will be fecal bile acid excretion and profile, short-chain fatty acid excretion and profile, colonic transit, and fecal microbiota. Secondary outcomes will be stool characteristics based on responses to validated bowel diaries. Stool samples will be collected from participants during the last 2 days of a 4-day 100 g fat diet and split into 3 samples for fecal microbiota, SCFA, and bile acid analysis.
Description
During the study: Screening/Visit 1 * Participants will be asked to read and sign this informed consent after all questions about the study have been answered to satisfaction. * This is a screening visit, and we may determine that a participant is ineligible to continue to participate in the study. * The study team will collect medication and medical history. * A physical exam will be performed by the physician. Vital signs and body measurements will be collected. * Participants will be provided with a take-home lasagna meal (vegetarian and non-vegetarian option) and dessert. * Participants…
Eligibility
- Age range
- 17–65 years
- Sex
- All
- Healthy volunteers
- Yes
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…
Interventions
- Dietary SupplementInulin
Inulin ingestion is not being used to diagnose, treat, or prevent IBS. Inulin is being used to study an individual's ability to ferment dietary fiber.
Location
- University of California, Los AngelesLos Angeles, California