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Completed

NCT Number: NCT05807919

Evaluating the Efficacy of the Mediterranean Diet to the Low- Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) Diet in Treating Irritable Bowel Syndrome(IBS)

This study is being completed to determine if the Mediterranean (MD) and low FODMAP (fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols) diets are comparable in the effectiveness to treat Irritable Bowel Syndrome (IBS).

The study team hypothesizes that:

* The low FODMAP and Mediterranean groups will achieve a similar improvement in abdominal pain * Both groups will achieve similar improvements in bloating, overall IBS symptom severity, and adequate relief

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Key information

Conditions

Irritable Bowel Syndrome Colonic Diseases Colonic Diseases, Functional Digestive System Diseases Gastrointestinal Diseases Intestinal Diseases

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Michigan

Ann Arbor, Michigan, 48109, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients with IBS-D (diarrhea-predominant IBS) or IBS-M (IBS with mixed subtype) diagnosed per Rome IV questionnaire and without any unexplained alarm features (rectal bleeding, weight loss, nocturnal symptoms, personal history of celiac disease, microscopic colitis, inflammatory bowel disease)
  • Aged 18-70 years at the time of screening
  • Weekly average of worst daily (in the past 24 hours) abdominal pain score of ≥3.0 on a 0-to-10-point scale
  • At least 80 percent compliance in daily questionnaire entries during the 7-day screening period

Exclusion criteria

  • Subjects adhering to any dietary IBS treatment such as the low-fodmap diet, or gluten-free diet, Mediterranean currently or within the past 6 months
  • Subjects with a known food allergy to eggs, seafood, peanuts, tree nuts or milk (subjects with lactose intolerance that are experiencing IBS symptoms while on a lactose-free diet will not be excluded from the study).
  • Subjects with a history of poorly controlled insulin-dependent or non-insulin-dependent diabetes
  • Subjects with a known history of organic Gastrointestinal (GI) disease (i.e., celiac disease, inflammatory bowel disease or microscopic colitis)
  • Subjects with a history of an eating disorder requiring medical or behavioral treatment within the past 10 years.
  • Subjects with prior small bowel or colonic surgery (excluding appendectomy or cholecystectomy if over 6 months since these 2 procedures)
  • Oral antibiotic use in the past 3 months
  • Any planned significant changes in dietary or exercise regimen within 30 days prior to Screening or during the study.
  • Currently pregnant or breastfeeding.

Treatment and study plan

Diet low in all FODMAP groups

Other

Randomized participants will eat this diet for 4 weeks (all meals and snacks will be provided). Participants will only eat the study food for this intervention. Participants will be asked to complete surveys, food diaries, and have blood and stools samples pre and post treatment.

Diet - Mediterranean

Other

Randomized participants will eat this diet for 4 weeks (all meals and snacks will be provided). Participants will only eat the study food for this intervention. Participants will be asked to complete surveys, food diaries, and have blood and stools samples pre and post treatment.

Primary outcomes

  1. Proportion of Participants Who Are Responders Based on the Abdominal Pain Intensity Score for at Least 2 of 4 Weeks

    Time frame: 4 weeks

    Results reflect the participants who were weekly responders for at least 2 of the 4 weeks based on their abdominal pain intensity score. The abdominal pain score was a single-question, 11-point numeric rating scale in which 0 represented no abdominal pain and 11 represented the worst possible abdominal pain. Once per day, subjects reported their worst daily (in the past 24 hours) abdominal pain. A weekly responder was defined as a participant whose score decreased in the weekly average of worst abdominal pain in the past 24 hours by at least 30% compared with baseline.

Secondary outcomes

  1. Proportion of Participants Who Are Weekly Responders to Adequate Relief Symptom Assessment for at Least 2 of 4 Weeks

    Time frame: 4 weeks

    Results reflect the participants who were weekly responders based on the adequate relief symptom assessment for at least 2 of the 4 weeks. Participants provided a binary (yes or no) response to rate the adequacy of relief of global irritable bowel syndrome (IBS) symptoms at the start of the study and weekly thereafter. A weekly responder was defined as a participant who achieved adequate relief in symptoms in at least 2 out of 4 weeks of the treatment period.

  2. Proportion of Participants Who Are Weekly Responders Based on the Irritable Bowel Severity Scoring System (IBS-SSS) Modified Version for at Least 2 of the 4 Weeks

    Time frame: 4 weeks

    Results reflect participants who were weekly responders for at least 2 of the 4 weeks based on their scores on a modified version of the IBS-SSS. This version of the IBS-SSS was comprised of 5 questions participants answered based on their stomach and bowels. The total score for this modified version of the IBS-SSS was 0-500, with 0 indicating no IBS symptoms and 500 indicating the highest amount of IBS symptoms. A weekly responder was defined as a participant whose score decreased in the weekly IBS-SSS by at least 50 points compared with baseline.

  3. Change in Mean Score of the Irritable Bowel Severity Scoring System (IBS-SSS) Modified Version

    Time frame: Baseline, 4 weeks

    The modified version of the IBS-SSS was comprised of 5 questions participants answered based on their stomach and bowels. The total score for this modified version of the IBS-SSS was 0-500, with 0 indicating no IBS symptoms and 500 indicating the highest amount of IBS symptoms. The results represent the mean change from baseline minus 4 weeks.

  4. Proportion of Participants Who Are Weekly Responders to Bloating for at Least 2 of the 4 Weeks

    Time frame: 4 weeks

    Results reflect the number of participants who were weekly responders based on their abdominal bloating score for at least 2 of 4 weeks. The abdominal bloating score was a single-question, 11-point numeric rating scale in which 0 represented no abdominal bloating and 11 represented the worst possible abdominal bloating. Once per day, participants reported their worst daily (in the past 24 hours) abdominal bloating. A weekly responder was defined as a participant whose score decreased in the weekly average of worst bloating in the past 24 hours by at least 30% compared with baseline.

  5. Participants Who Are Weekly Responders to Stool Consistency Based on the Bristol Stool Scale (BSS) for at Least 2 of the 4 Weeks

    Time frame: 4 weeks

    Results reflect the participants who were weekly responders based on their stool consistency assessment for at least 2 of 4 weeks. A stool consistency weekly responder was defined as a participant with a 50% or greater reduction in the number of days per week with at least one abnormal stool. Stools that scored as 1 or 2 (hard stool) or 6 or 7 (liquid stool) on the BSS were defined as abnormal.

Sponsors and collaborators

Lead sponsor

University of Michigan

Other

Collaborators

  • ModifyHealth
  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Registry information

Official study title

Evaluate and Compare the Clinical Efficacy of the Mediterranean Diet to the Low-FODMAP Diet in Treating Irritable Bowel Syndrome

Important dates

Study start
2023
Primary completion
2023
Study completion
2023
First posted
Apr 11, 2023
Registry last updated
Mar 28, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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