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NCT Number: NCT05810168

Traditional Dietary Advice Versus Low FODMAP Diet in Postprandial Functional Dyspepsia

Functional dyspepsia is common, affecting 7.2% of the global population, and associated with substantial health impairment. Almost 80% of patients with functional dyspepsia report meal-related symptoms and are classified as having the postprandial distress syndrome (PDS) variant. However, studies evaluating dietary modifications in PDS are sparse.

The investigators will perform a randomised trial evaluating traditional dietary advice (TDA) vs. a diet low in fermentable fermentable oligo-, di-, mono- saccharides and polyols (low FODMAP diet) in PDS.

70 patients with PDS will be randomly assigned TDA or a low FODMAP diet. The TDA group will be recommended to eat small, regular meals and reduce the intake of caffeine/alcohol/fizzy drinks, fatty/processed/spicy foods, and fibre. The low FODMAP diet group will be advised to exclude fermentable carbohydrates, which are present in wheat-based products, many fruits/vegetables, pulses, beans, dairy, and sweeteners.

Questionnaires are to be completed during the 6-week trial, including self-reported adequate relief of dyspeptic symptoms, and the validated Leuven Postprandial Distress Scale (LPDS), Gastrointestinal Symptom Rating Scale, and Nepean Dyspepsia Quality of Life Index.

The primary endpoint to define clinical response will be evaluated over weeks 4-6 as >0.5-point reduction in the PDS subscale of the LPDS (calculated as the mean scores for early satiety, postprandial fullness, and upper abdominal bloating).

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Key information

Conditions

Dyspepsia Digestive System Diseases Functional Gastrointestinal Disorders Gastrointestinal Diseases Pathological Conditions, Signs and Symptoms Signs and Symptoms Signs and Symptoms, Digestive

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Royal Hallamshire Hospital

Sheffield, South Yorkshire, S10 2JF, United Kingdom

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Fulfil Rome IV symptoms criteria for postprandial functional dyspepsia
  • Normal upper gastrointestinal endoscopy within last 3years
  • Online access
  • English literate

Exclusion criteria

  • Organic gastrointestinal diseases (e.g. inflammatory bowel disease, GI cancer, coeliac disease)
  • Major abdominal surgery (except laparoscopy, appendectomy, cholecystectomy)
  • Documented H.pylori in the last 3 months
  • History of eating disorders
  • Body mass index <20
  • Current dietary interventions
  • Current use of opioids or anti-inflammatory drugs
  • Severe systemic disease (e.g. cardiac, renal, respiratory) necessitating frequent medical consultations)
  • Pregnant
  • Diabetes mellitus
  • Scleroderma
  • Memory impairment

Treatment and study plan

Dietary modifications

Other

TDA and low FODMAP diet

Primary outcomes

  1. Proportion of clinical responders between traditional dietary advice vs. a Low FODMAP diet on the leuven postprandial distress scale (LPDS)

    Time frame: 6 weeks

    The Leuven Postprandial Distress Scale (LPDS) assesses the severity of 8 upper gastrointestinal symptoms scored from 0 (none) to 4 (very severe). A difference of 0.5 from baseline for the cardinal PDS symptoms (average of first 3 questions) will be used as a cut-off to determine clinical response by comparing average pre-treatment scores with the average score during weeks 4-6.

Secondary outcomes

  1. Proportion of clinical responders between traditional dietary advice vs. a low FODMAP diet

    Time frame: 6 weeks

    Self-reported adequate relief of dyspeptic symptoms as a binary answer (yes or no). A responder will be defined if ≥50% adequate relief of dyspeptic symptoms during weeks 4-6

  2. Changes in Gastrointestinal Symptom Rating Irritable Bowel syndrome Scale

    Time frame: 6 weeks

    The validated Gastrointestinal Symptom Rating Scale assesses the symptoms of irritable bowel syndrome, depicting problems with satiety, abdominal pain, diarrhoea, constipation and bloating. Higher scores represent greater symptom severity. Change in scores will be compared within- and between- groups.

  3. Changes in Napean Dyspepsia-related Quality of Life Index

    Time frame: 6 weeks

    The Napean Dyspepsia Scale is a validated questionnaire assessing dyspepsia-related quality of life syndrome, with higher scores representing worse quality of life. Change in scores will be compared within- and between- groups

  4. Changes in Hospital Anxiety and Depression scale

    Time frame: 6 weeks

    The Hospital Anxiety and Depression Scale is a validated questionnaire assessing mood, with higher scores representing worse mood. Change in scores will be compared within- and between- groups

  5. Changes in Somatic Symptom reporting

    Time frame: 6 weeks

    The validated patient health questionnaire-12 assess extra-intestinal somatic symptoms, with higher scores representing greater somatic symptom severity. Change in scores will be compared within- and between- groups

  6. Changes in nutritional intake

    Time frame: 6 weeks

    The Comprehensive Nutritional Assessment Questionnaire assesses macronutrient and micronutrient intake, FODMAPs, fibre, starch, glycaemic index/load. Change in scores will be compared within- and between- groups

Sponsors and collaborators

Lead sponsor

Sheffield Teaching Hospitals NHS Foundation Trust

Other

Registry information

Official study title

Randomised Trial of Traditional Dietary Advice Versus a Low FODMAP Diet in Postprandial Functional Dyspepsia

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Apr 12, 2023
Registry last updated
May 1, 2026

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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