Irritable Bowel Syndrome and Control Volunteers: Diet Challenge

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

The purpose of this study is to study the relationship between the bile acids, short chain fatty acids and bacteria within the intestines. The hypothesis is that changes in the bacterial composition of the stool are associated with the differences in bile acids and short chain fatty acids in patients having irritable bowel syndrome compared to healthy individuals.

Study Overview

• Status: Terminated
• Conditions: IBS - Irritable Bowel Syndrome
• Intervention / Treatment: Dietary supplement: Inulin

Detailed Description

The Study involves 3 visits and will in include 3 types of subjects - those who have irritable bowel syndrome (IBS) with constipation (IBS-C), IBS with diarrhea (IBS-D) and those who have no IBS symptoms or diagnosis.

Visit 1

• Volunteers will read and sign this informed consent after all questions about the study have been answered
• This is a screening visit and we may determine that volunteers ineligible to continue to participate in the study.
• Volunteers will have a medical history taken including demographics, history of symptoms and illness
• Volunteers will be asked about all medications
• A physical exam will be performed by the physician.
• Vital signs will be measured.
• Urine Pregnancy test may be done for woman in the reproductive age range.
• Eligible participants will be provided with a take-home lasagna meal.
• Participants will be given instructions and supplies for collection, storage and transportation of stool for the next visit.
• Participants will be provided with instructions for a low fiber, high fat diet which should be consumed for 2 days before stool collection and during the 2 days of stool collection. Instructions will also come with materials to allow participants to record diet intake during these 4 days.
• Participants will be provided a bowel pattern diary to record bowel symptoms over the course of the study

Day 1: this may be the same as Visit 1 or it may be a different day. It will depend upon the day that participants can make it back to the clinic for the Day 5 visit.

Day 2-4 (at home):

• Participants record stool symptoms and patterns in a diary daily starting from Day 2 to Day 5.
• During this time, participants will be instructed to consume a low fiber diet, avoid alcohol, and start a 4-day 100 g fat diet.
• On the evening before Day 5, a standardized, completely digestible, and non-fermentable meal (lasagna) will be consumed which will be provided to you on Day 1.
• Participants will collect stool at home on Day 4 and 5 and store as per instructions provided on Visit 1. They will

Day 5 (Visit 2):

• Participants return to the clinic on Day 5 after an overnight fast.
• You will receive a standard breakfast and lasanga meal with 10 g inulin (Orafti®) powder and 200 mL of water.
• Take-home meals will be provided (white bread sandwich with ham or cheese) to be consumed at 4 and 8 hours after breakfast.

Day 6 (Visit 3):

• Participants will return to the clinic in order to return stool collections and the daily diaries.
• Participants may also submit diaries by fax or email.

Day 30-90

• Optional dietary follow-up (Day 30-90): To further assess the utility of the 24 hour dietary recall, willing participants will be invited to participate in a an optional follow-up activity during which they will complete the Automated Self-Administered Dietary Assessment Tool with or without assistance of a trained interviewer. Interested volunteers will be contacted by phone and provided instructions on how to complete the tool online by the study team.

• Study Type: Interventional
• Enrollment (Actual): 29
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Indiana
    • Indianapolis, Indiana, United States, 46202
      • Indiana University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Patients with IBS, ages 18-65 fulfilling Rome IV criteria and asymptomatic controls with no prior history of GI disease or symptoms.
• Participants should be on a stable and consistent diet regimen and should not be following an extreme diet intervention such as gluten-free or a low FODMAP diet at the time of study participation.

Exclusion Criteria:

• Participants with microscopic/lymphocytic/collagenous colitis, inflammatory bowel disease, celiac disease, visceral cancer, chronic infectious disease, immunodeficiency, uncontrolled thyroid disease, history of liver disease or history of elevated AST/ALT > 2.0x the upper limit of normal
• Prior radiation therapy of the abdomen or abdominal surgeries except for C-section, tubal ligation, vaginal hysterectomy and appendectomy or cholecystectomy, > 6 months prior to study initiation.
• Ingestion of any prescription, over the counter, or herbal medications which can affect GI transit or study interpretation (e.g. opioids, narcotics, anticholinergics, norepinephrine reuptake inhibitors, nonsteroidal anti-inflammatory drugs, COX-2 inhibitors, bile acid sequestrants) within 6 months of study initiation for asymptomatic volunteers or within 2 days before study initiation for IBS patients. Rescue therapy to facilitate stool collection will be permitted where needed.
• Any females who are pregnant or trying to become pregnant or breast-feeding
• Antibiotic usage within 3 months prior to study participation
• Prebiotic or probiotic usage within the 2 weeks prior to study initiation
• Regular use of tobacco products within the past 6 months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Healthy volunteers; Adults ages 18-65 years with no prior history of gastrointestinal diseases or symptoms.	Dietary supplement: Inulin; 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.
Experimental: Irritable Bowel Syndrome Patients with Diarrhea; Patients with irritable bowel syndrome (IBS) with diarrhea, ages 18-65 years fulfilling Rome IV criteria for IBS	Dietary supplement: Inulin; 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.
Experimental: Irritable Bowel Syndrome Patients with Constipation; Patients with irritable bowel syndrome (IBS) with constipation, ages 18-65 years fulfilling Rome IV criteria for IBS	Dietary supplement: Inulin; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Fecal Bile Acids	Stool samples will be collected over 2 days for measurement of fecal bile acids (mcmol/48h) by high performance liquid chromatography-mass spectometry	48 hours
Total Fecal Short Chain Fatty Acids	Stool samples will be collected for measurement of measurement of short chain fatty acids (mmol/kg) by liquid chromatography-mass spectrometry	48 hours
Individual Fecal Short Chain Fatty Acids - Acetate	Stool samples will be collected for measurement of measurement of short chain fatty acids (mmol/kg) by liquid chromatography-mass spectrometry	48 hours
Individual Fecal Short Chain Fatty Acids - Propionate	Stool samples will be collected for measurement of measurement of short chain fatty acids (mmol/kg) by liquid chromatography-mass spectrometry	48 hours
Individual Fecal Short Chain Fatty Acids - Butyrate	Stool samples will be collected for measurement of measurement of short chain fatty acids (mmol/kg) by liquid chromatography-mass spectrometry	48 hours
Fecal Microbial Population	Stool samples will be be collected from participants for nucleic acid extraction, shotgun sequencing is used to measure microbial communities and profiles of specimens. Shannon index is calculated to measure the diversity of species. The minimum value is 0. There is no upper limit. The higher the Shannon index is, the greater the diversity of species is.	48 hours
Fecal Inulin	Fecal inulin content will be measured using short acid hydrolysis and high-performance liquid chromatography	48 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percent Primary Fecal Bile Acids	Stool samples will be collected over 2 days for measurement of fecal bile acids (mcmol/48h) by high performance liquid chromatography-mass spectrometry. Percent primary bile acids is then calculated as primary bile acids divided by total bile acids multiplied by 100.	48 hours
Stool Characteristics - Stool Frequency in 4 Days	Stool characteristics will be measured using a 4 day bowel diary. Stool frequency is the total number of bowel movements in 4 days summarized on the subject level.	4 days
Stool Characteristics - Stool Form	Stool characteristics will be measured using a 4 day bowel diary. Stool form is on a scale from 1 to 7, where 1=hard lumps, 2=lumps sausage,3=cracked sausage, 4=normal, 5=soft lumps, 6=mushy,7=watery, summarized on the level of bowel movements.	4 days
Stool Characteristics - Ease of Passage	Stool characteristics will be measured using a 4 day bowel diary. Ease of passage is on a scale from 1 to 7, where 1=manual disimpaction, 2=enema needed, 3=straining needed, 4=normal, 5=urgent without pain, 6=urgent with pain, 7=incontinent, also summarized on the level of bowel movements.	4 days

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Energy	Optional 24-hour dietary intake will be submitted using web-based Automated Self-Administered Dietary Assessment Tool developed by the National Cancer Institute (https://epi.grants.cancer.gov/asa24/). Dietary intake within a 24-hour period in 30-90 days after study enrollment were collected.	24 hours

Collaborators and Investigators

• Sponsor: Indiana University
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Investigators: Principal Investigator: Huiping XU, Indiana University

Study record dates

Study Major Dates

• Study Start (Actual): August 13, 2019
• Primary Completion (Actual): July 31, 2023
• Study Completion (Actual): July 31, 2023

Study Registration Dates

• First Submitted: June 6, 2019
• First Submitted That Met QC Criteria: June 7, 2019
• First Posted (Actual): June 12, 2019

Study Record Updates

• Last Update Posted (Actual): April 30, 2025
• Last Update Submitted That Met QC Criteria: April 11, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: prebiotic; microbiome; microbiota; bile acids; short chain fatty acids
• Additional Relevant MeSH Terms: Pathologic Processes; Intestinal Diseases; Disease; Digestive System Diseases; Gastrointestinal Diseases; Colonic Diseases; Colonic Diseases, Functional; Irritable Bowel Syndrome; Syndrome
• Other Study ID Numbers: 1903209172; K23DK122015 (U.S. NIH Grant/Contract)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No