An interventional study of Mediterranean Standard Diet and Mediterranean Modified Low FODMAP Diet in Irritable Bowel Syndrome, sponsored by University Hospital of Patras. Not yet recruiting. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-10-28.
Sponsored by University Hospital of Patras · Not applicable, Interventional, and Treatment
Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder with a significant impact on the quality of life of patients. Its global prevalence varies considerably, estimated at up to 10%, due to differences in diagnostic criteria, cultural factors and dietary patterns. Dietary interventions have emerged as first-line strategies for symptom management, with the low Fermentable Oligo-, Di-, and Monosaccharides and Polyols (FODMAP) diet demonstrating strong efficacy in reducing gastrointestinal symptoms by minimizing poorly absorbed, fermentable carbohydrates. However, concerns about long-term nutritional adequacy, potential alterations in gut microbiota composition, and sustainability of the low-FODMAP diet have led to the need for more comprehensive and nutritionally balanced dietary models.
In contrast, the Mediterranean Diet (MD), is widely recognized for its anti-inflammatory, cardiometabolic, and potential anticancer effects. Notably, adherence to the MD has been associated with favorable gut microbial profiles and a reduced risk of colorectal and other gastrointestinal cancers. However, the high FODMAP content of many components of the MD may limit its direct compatibility with dietary protocols for IBS. Incorporating the principles of the MD into a low-FODMAP dietary approach offers a promising strategy for enhancing the nutritional quality, sustainability, and long-term effectiveness of dietary management in IBS.
The aim of the study is to investigate and compare the effectiveness of a Mediterranean Modified Low FODMAP diet (Med-Mod LFD) with standard Mediterranean dietary recommendations (Med standard) in managing the symptoms of IBS. Specifically, the study aims to evaluate the impact of the two dietary interventions on the frequency and severity of gastrointestinal symptoms, to examine potential differences in quality of life, to assess patient compliance and acceptance of the two dietary approaches, and to explore whether the Med-Mod Low FODMAP variation of the Mediterranean diet offers advantages over the classical Mediterranean diet without compromising the health-promoting characteristics that make it beneficial.Dietary intake will also be assessed using a three-day food diary, which will be used for the dietary analysis of participants' food intake and for the assessment of macro- and micronutrient intake of the two dietary interventions
1,116 studies on the registry are indexed under Irritable Bowel Syndrome; 208 are open to participants now.
This study's planned enrollment of 108 is above the median of 70 across 896 interventional studies indexed under Irritable Bowel Syndrome.
Browse Irritable Bowel Syndrome studies →University Hospital of Patras is the lead sponsor of 43 studies on the registry; 11 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants in this group will be instructed to follow Mediterranean diet recommendations, based on the Greek National Dietary Guidelines, for the management of Irritable Bowel Syndrome for a period of 6 weeks.
Other: Mediterranean Standard Diet
All participants in this group will initially follow the Mediterranean Modified Low FODMAP Diet during Phase 1 (the elimination phase) for 6 weeks. During Phase 2 (the reintroduction phase), patients will gradually reintroduce foods high in FODMAPs over a period of 6-8 weeks and assess their individual tolerance. During Phase 3 (the maintenance phase), following the reintroduction of high-FODMAP foods, patients will follow an individualized diet based on their personal tolerance, combining high- and low-FODMAP foods.
Other: Mediterranean Modified Low FODMAP Diet
Mediterranean diet recommendations for a period of 6 weeks
Mediterranean-modified low-FODMAP dietary program, including elimination, reintroduction and personalization/maintenance phases
Change in symptom severity from baseline to post-intervention, assessed using a validated disease-specific questionnaire.
The Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) consists of five items, each accompanied by specific scoring instructions. The five items assess pain severity, pain frequency, severity of abdominal distension, satisfaction with bowel habits, and the impact of IBS on quality of life. Each item is scored from 0 to 100 using a visual analogue scale (VAS), yielding a total score ranging from 0 to 500, with higher scores indicating greater symptom severity. Patients may be classified as having mild (75-175), moderate (175-300), or severe (\>300) IBS. A reduction of 50 points is considered clinically meaningful.
Time frame: Baseline, 6 Weeks and 6 months
Assessment of IBS-related quality of life using a disease-specific questionnaire before and after the intervention, with comparisons between the study groups.
The Irritable Bowel Syndrome Quality of Life (IBS-QOL) is a self-reported, disease-specific measure that assesses the extent to which IBS has affected patients' quality of life during the previous 30 days. It includes eight domains: dysphoria, interference with activity, body image, health worry, food avoidance, social reactions, sexual concerns, and relationships. Each item is rated on a 5-point Likert scale, with higher scores indicating poorer quality of life. The total raw score ranges from 34 to 170. A reduction of at least 10 points is considered a clinically meaningful improvement.
Time frame: Baseline, 6 weeks and 6 months
Bristol Stool Form Scale (BSFS), Type 1-7
Stool consistency will be assessed using the Bristol Stool Form Scale, a 7-point categorical scale ranging from Type 1 (separate hard lumps) to Type 7 (watery stool with no solid pieces). Higher scores indicate progressively softer and looser stool consistency. Because both ends of the scale represent abnormal consistency - Types 1-2 indicating hard stool/constipation and Types 6-7 indicating loose/watery stool/diarrhea - the scale is not unidirectional, and neither a higher nor a lower score represents a uniformly better or worse outcome. Types 3-4 represent normal stool consistency and are generally considered the optimal range.
Time frame: baseline, 6 weeks and 6 months
Assessment of anxiety and depressive symptoms before and after the intervention.
The Hospital Anxiety and Depression Scale (HADS) is used to assess symptoms of anxiety and depression. It comprises 14 items divided into two seven-item subscales: anxiety (HADS-A) and depression (HADS-D). Each item is rated on a 4-point response scale ranging from 0 to 3. The score for each subscale is calculated by summing the corresponding seven items and ranges from 0 to 21. A score of 0-7 indicates no clinically relevant symptoms, 8-10 indicates mild symptoms, and a score of ≥11 indicates more severe symptoms of anxiety or depression.
Time frame: Baseline, 6 weeks and 6 months
Mediterranean Diet Adherence Score
The Mediterranean Diet Adherence Screener (MEDAS) is a 14-item questionnaire used to assess adherence to the Mediterranean diet. The items evaluate the consumption of key components of the Mediterranean dietary pattern, including whole grains, fruits, vegetables, legumes, fish, meat and meat products, poultry, full-fat dairy products, sweets, olive oil, and alcohol. The total MEDAS score ranges from 0 to 14, with higher scores indicating greater adherence. Adherence is classified as low (≤5), moderate (6-9), or high (≥10).
Time frame: Baseline, 6 weeks and 6 months
No study locations are listed for this record.
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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University Hospital of Patras