Traditional Dietary Advice Vs. Mediterranean Diet in IBS

NCT05985018 | Completed

• 1 other identifier: STH20655b
• Study Type: interventional
• Target: 139
• Locations: 1 country
• Sites: 1

Brief Summary

Irritable bowel syndrome (IBS) affects 5-10% of the population, and incurs substantial health impairment and healthcare utilization. Over 80% of individuals with IBS report food to trigger or aggravate symptoms, with many seeking to undertake dietary modifications. Current guidelines recommend first-line therapy with the relatively straightforward traditional dietary advice, with the more complex and restrictive low FODMAP diet reserved as second-line therapy. There is emerging data suggesting that the Mediterranean diet may also improve the symptoms of IBS, although it has not yet been subject to any head-to-head randomized dietary trials to help position it within the treatment algorithm. Given the relative ease of implementing the Mediterranean diet, alongside its recognized cardio-metabolic and mental health benefits, studying its efficacy in IBS is attractive as it could potentially pave the way for another first-line dietary option being available to patients before escalating to the demanding and resource intensive second-line therapies. The investigators will perform a randomized trial comparing the clinical efficacy of traditional dietary advice vs. a Mediterranean diet in IBS. Following dietary randomization, participants will complete validated questionnaires to assess changes in IBS symptoms, quality of life, mood, somatic symptoms, nutritional status, as well as dietary satisfaction and adherence.

Conditions

Irritable Bowel Syndrome

Outcome Measures

Primary Outcomes (1)

• Proportion of IBS patients experiencing clinical response with traditional dietary advice vs. Mediterranean diet

  IBS symptom severity scale (IBS-SSS) where a 50-point reduction denotes a meaningful clinical response

  Baseline to Week 6

Secondary Outcomes (7)

• Changes in individual items of the IBS-SSS

  Baseline to Week 6

• Changes in Anxiety and Depression

  Baseline to Week 6

• Changes in Somatic Symptom reporting

  Baseline to Week 6

• Changes in quality of life

  Baseline to Week 6

• Dietary satisfaction to assigned intervention

  Week 6

Study Arms (2)

Traditional Dietary Advice

ACTIVE COMPARATOR

Its main elements are to adopt sensible eating habits and avoid excess fatty foods, spicy foods, processed foods, caffeine, fizzy drinks and alcohol.

Other: Traditional Diet

Mediterranean Diet

ACTIVE COMPARATOR

The principle components is a diet rich in vegetables, pulses, whole grains, and olive oil

Other: Mediterranean Diet

Interventions

Traditional Diet OTHER

Provided as an educational leaflet

Traditional Dietary Advice

Mediterranean Diet OTHER

Provided as an educational leaflet

Mediterranean Diet

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• IBS Symptom Severity Scale(IBS-SSS) \> 75
• Online access
• English literate

You may not qualify if:

• Organic gastrointestinal diseases (e.g. inflammatory bowel disease, GI cancer, coeliac disease, microscopic colitis, bile acid diarrhoea)
• Major abdominal surgery (except laparoscopy, appendectomy, cholecystectomy)
• History of eating disorder
• Body mass index \<20
• Current dietary interventions
• Current use of opioids/antibiotics
• Titrating dose of neuromodulators
• Severe systemic disease (e.g. cardiac, renal, respiratory, psychiatric) necessitating frequent medical consultations/hospitilisations
• Pregnant
• Diabetes mellitus
• Scleroderma
• Memory impairment

Sponsors & Collaborators

• Sheffield Teaching Hospitals NHS Foundation Trust: lead

Study Sites (1)

Royal Hallamshire Hospital

Sheffield, South Yorkshire, S10 2JF, United Kingdom

Location

Related Publications (1)

• Bamidele JO, Brownlow GM, Flack RM, Buckle RL, Shaw CC, Shiha MG, Aziz I. The Mediterranean Diet for Irritable Bowel Syndrome : A Randomized Clinical Trial. Ann Intern Med. 2025 Dec;178(12):1709-1717. doi: 10.7326/ANNALS-25-01519. Epub 2025 Oct 28.

  PMID: 41144975 DERIVED

MeSH Terms

Conditions

Irritable Bowel Syndrome

Interventions

Diet, Mediterranean

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases

Intervention Hierarchy (Ancestors)

Diet, Plant-Based; Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Imran Aziz

  Sheffield Teaching Hospitals NHS Foundation Trust

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 25, 2023
• First Posted: August 9, 2023
• Study Start: September 30, 2023
• Primary Completion: December 20, 2024
• Study Completion: December 20, 2024
• Last Updated: March 14, 2025

Record last verified: 2025-03

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)