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

Not Applicable

Completed

Conditions: Irritable Bowel Syndrome

Interventions: Other: Diet - Mediterranean
Other: Diet low in all FODMAP groups

Registration Number: NCT05807919

Lead Sponsor: University of Michigan

Brief Summary: 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

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 26

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.

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Diet - Mediterranean	Diet - Mediterranean	-
Diet low in all FODMAP groups	Diet low in all FODMAP groups	-

Primary Outcome Measures

Name	Time	Method
Proportion of Participants Who Are Responders Based on the Abdominal Pain Intensity Score for at Least 2 of 4 Weeks	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 Outcome Measures

Name	Time	Method
Proportion of Participants Who Are Weekly Responders to Adequate Relief Symptom Assessment for at Least 2 of 4 Weeks	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.
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	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.
Change in Mean Score of the Irritable Bowel Severity Scoring System (IBS-SSS) Modified Version	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.
Proportion of Participants Who Are Weekly Responders to Bloating for at Least 2 of the 4 Weeks	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.
Participants Who Are Weekly Responders to Stool Consistency Based on the Bristol Stool Scale (BSS) for at Least 2 of the 4 Weeks	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.