An interventional study of Low FODMAP diet and Gentle FODMAP diet in Functional Gastrointestinal Disorders (FGIDs), Irritable Bowel Syndrome (IBS) and Functional Dyspepsia, sponsored by Universiti Kebangsaan Malaysia Medical Centre. Recruiting at 1 site in Malaysia. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-25.
Sponsored by Universiti Kebangsaan Malaysia Medical Centre · Not applicable, Interventional, and Treatment
Brief Summary :
The goal of this clinical trial is to investigate the effects of differing FODMAP diets on gut microbiota, gut barrier function, symptom severity, quality of life, and psychological status in FGID patients. The main question it aims to answer is :
How does diets with differing FODMAP content affect the gut microbiota, gut barrier function, symptom severity, psychological status and quality of life in patients with FGID ? Researchers will compare low FODMAP diet, Gentle FODMAP diet and Traditional Dietary Advice (NICE guidelines) to see which diet is more suitable and effective for Malaysian FGID patients.
Participants will :
Be given either low FODMAP diet, Gentle FODMAP diet or Traditional Dietary Advice intervention and will be required to follow the intervention for two weeks.
Be required to provide stool and blood samples during baseline and intervention Record 4 day food diary and complete assessing questionnaires during baseline and intervention
Functional Gastrointestinal Disorder (FGIDs), including irritable bowel syndrome (IBS) and functional dyspepsia (FD), are prevalent conditions that effects about 40% of world population and 21% of Malaysian population. They represent a significant health burden, impacting patients' quality of life. While the low FODMAP diet is effective in managing FGID around the western region, there is limited research done on comparing the impacts of diets with differing FODMAP content on symptom severity, quality of life, gut microbiota and gut barrier function of FGID patients in the Asian region as low FODMAP is restrictive. Therefore, conducting a randomised controlled trial is vital in measuring the effectiveness of diet with differing FODMAPs on FGID patients.
The objectives of this study are :
This study would be able to provide significant understanding of dietary management of FGID. Conducting this study would provide critical insights into the role of gut microbiota and gut barrier function in the pathophysiology of FGID, highlighting how dietary modulation can impact overall symptom management.
The study design involve screening and recruiting participants, followed by baseline data collection, randomisation, group allocation, and intervention with data collection.
First Visit (Day 1) During baseline, vital information such as socio demographic data will be gathered and FGID screening will be conducted using the ROME III Asian Diagnostic Questionnaire for Adults which consists of the Irritable Bowel Syndrome module and the Gastroduodenal Disorders module. A total of 5 questionnaires will be provide to the participants. These are Irritable Bowel Syndrome Severity Scale (IBS-SSS), Gastrointestinal Symptom Rating Scale (GSRS), Food avoidance and Dietary trigger questionnaire, Hospital Anxiety and Depression Scale (HADS), and the EQ-5D-5L questionnaire.
Body weight and composition of participants will be assessed using the Tanita Body Composition scale, whereas height of participants will be measured using a stadiometer. Dietary and FODMAPs will be estimated using a 4-day food diary (3 weekdays, 1 weekend). Additionally, blood sample will be collected from participants for further assessment. 10 ml blood will be drawn from each participant to detect serum biomarkers. Stool bottle will be provided to participants for stool collection upon the next visit. Stool collection is implemented to assess participants' gut integrity and gut microbiota. After concluding the baseline assessments, patients will be randomised into three groups. Groups A, B and C will follow a restricted FODMAP diet (LFD), Gentle FODMAP diet and traditional dietary advice (TDA), respectively. Participants will be randomly assigned to a study arm by a computer-generated randomisation program using the open-access website www.randomization.com at a ratio of 1:1:1.
Second Visit (Day 8) Participants will return their stool sample and completed diary. The diary will be assessed for completion, and the stool sample will be collected and frozen per protocol. Based on randomisation, participants in the LFD group will be provided with restricted FODMAP advice. In contrast, those in the GFD group will be given general healthy advice by dietitians/researchers trained in delivering the diet. Meanwhile, participants in the TDA group will be given an overall healthy dietary intervention and counselling. All three groups will be advised to follow their respective diets for two weeks. A food diary and another stool collection bottle will be provided.
Phone follow up (Day 15) A phone follow-up is scheduled after a week to remind participants to complete their food diary, answer any doubts or questions relating to their allocated intervention and subsequently plan their next visit.
Final visit (Day 22) Visit 3 will be scheduled after 2 weeks of intervention. Participants will return their stool samples, food diary, and questionnaire. They will also complete two symptom severity questionnaires, food avoidance and dietary trigger questionnaire, with questionnaires to assess quality of life and psychological status and provide a non-fasting blood sample. Additionally, participants in the LFD group will be provided advice on reintroduction. Those who have completed the study will be given an inconvenience allowance.
1,116 studies on the registry are indexed under Irritable Bowel Syndrome; 208 are open to participants now.
This study's planned enrollment of 60 is below the median of 70 across 896 interventional studies indexed under Irritable Bowel Syndrome.
Browse Irritable Bowel Syndrome studies →Universiti Kebangsaan Malaysia Medical Centre is the lead sponsor of 58 studies on the registry; 8 are open to participants now.
Compared within Irritable Bowel Syndrome, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Gastrointestinal Diseases. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
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.
Low FODMAP diet will be administered for two weeks
Behavioral: Low FODMAP diet
Gentle FODMAP diet will be administered for two weeks
Behavioral: Gentle FODMAP diet
Traditional Dietary advice will be administered for two weeks
Behavioral: Traditional Dietary Advice
High FODMAP foods are swapped for low FODMAP alternatives, for two weeks (Elimination phase)
Key High FODMAP foods will be identified from patients' food diaries and swapped with low FODMAP alternatives. (Elimination phase)
Subjects are required to follow a set of healthy eating guidelines set by NICE guidelines for IBS for two weeks a. Have regular meals and take time to eat b. Avoid missing meals or leaving long gaps between eating c. Drink at least eight cups of fluid a day, especially water or other non-d. caffeinated drinks, such as herbal teas d. Restrict tea and coffee to three cups a day e. Reduce intake of alcohol and fizzy drinks . Limit intake of high-fibre food g. Reduce intake of resistant starch h. Limit fresh fruit to three portions a day
Effect of FODMAP restrictions on Gut Microbiota Abundance and Diversity
16s RNA gene seqeuncing will be conducted on the stool samples at both baseline and post-intervention timelines. This test would target the microbial diversity by assessing the abdundance of key bacterial taxa.
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Effect of FODMAP restrictions on Gut Barrier Function
The stool samples collected would be subjected to zonulin test and short-chain fatty acid quantification (SCFA) in order to assess gut barrier function of subjects at baseline and post-intervention timelines. Zonulin is a protein that reversibly modulates the intestinal permeability, while SCFA such as butyrate are by-products of the carbohydrate fermentation facilitated by gut microbiome that enhances the integrity of tight junction of the intestinal barrier
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Effect of 2 week FODMAP restrictions on Symptom Severity (IBS-SSS questionnaire)
Irritable Bowel Syndrome Symptom Severity Score (IBS-SSS) and Gastrointestinal Symptom Rating Scale (GSRS) will be filled out by subjects during baseline and post-intervention to assess symptom severity. For IBS-SSS, Four out of five items have visual analogue scales to describe the level of severity of abdominal pain, bloating or distension, disturbance of bowel habits and life impact of IBS symptoms. The level of severity will be categorised based on their total scores. A score of less than 25% is considered no pain, 25 to 50% is considered mild, 50 to 75% is considered moderate, and the score of 100% is very severe.
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Effect of 2-week FODMAP restriction on Psychological Status
Hospital Anxiety and Depression Scale (HADS) will be filled out by subjects during baseline and post-intervention to assess symptom severity. This self-reported questionnaire contains 14 items that are scored on a 4-point Likert-type scale, ranging from 0 to 3, and are classified into two subscales measuring cognitive and emotional symptoms of depression (HADS-D) and anxiety (HADS-A). The total score on each subscale ranges from 0 to 21, and a higher score represents worse symptoms. A score equal to or greater than eight on either HADS-D or HADS-A is considered a 'possible case', and above 11 a 'probable case'.
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Effect of 2-week FODMAP restriction on Quality of Life
European Quality of Life 5 Dimensions 5 Level Version Questionnaire (EQ-5D-5L) will be filled out by subjects during baseline and post-intervention to assess quality of life. This validated questionnaire consists of five items capturing different aspects of health, including mobility, self-care, ability to carry out usual activities, pain/discomfort and anxiety/depression. Each item has five levels of responses, where the minimum level being 'no problems' and maximum level being 'unable to do' things mentioned.
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Effect of 2-week FODMAP restriction on Food Avoidance
A validated food avoidance and dietary trigger questionnaire will be filled out by subjects during baseline and post-intervention to assess food avoidance. This questionnaire is a 10-item tool in which question 1 is to identify dietary triggers of subjects. Question 2, 3, and 4 are follow up questions to assess bowel symptoms and dietary triggers. Question 5 that assess fear of eating, has a 6-point Likert scale, where the minimum point is 'Strongly Disagree' and the maximum point is 'Strongly Agree'.Question 6 assesses food avoidance behaviour using a 4-point Likert scale, where the minimum point is 'Never' and the maximum point is 'Always'. Questions 6,7,8,9 and 10 are used to assess patient's medical knowledge and medical history.
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Effect of 2 week FODMAP restrictions on Anthropometry
The anthropometry parameters such as weight (in kilograms), height (in centimetres), and body mass index (BMI) (kg/m\^2) will be assessed using standard protocols. To measure changes in body composition, weight, and BMI, the Body Impedance Analysis (BIA) will be used. Parameters such as percentage of body fat (%), visceral fat, muscle mass (kg) and total body water (%) will be measured.
Time frame: Measurement before (Day 1) and after the diet (Day 22)
FODMAP Intake Before and After Intervention
FODMAP intake will be estimated from the 4-day food diary (3 weekdays, 1 weekend) given to subjects both before intervention and after following 2-week intervention. FODMAP intake will be estimated using the Monash University Database
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Effect of 2-week FODMAP restrictions on Symptom Severity (GSRS questionnaire)
The Gastrointestinal Symptom Rating Scale (GSRS) will be filled out by subjects during baseline and post-intervention to assess symptom severity. GSRS is 13 item questionnaire that are scored on a 7-point Likert scale, with the minimum point being 'no discomfort at all' and maximum value being 'very severe discomfort'.
Time frame: Measurement before (Day 1) and after the diet (Day 22)
Plan to share: No — We will not be sharing individual patient data to the trial registry to protect participant confidentiality, as institutional policies restrict such disclosure.
Ran from Jul 2025 to primary completion in Sep 2026, 14 months.
Of 305 non-industry interventional studies with no phase under Irritable Bowel Syndrome, half reached primary completion within 21 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 40. This study's 14 months is below that.
Counting every sponsor, half of 357 studies reached it within 19 months; a quarter within 9 and three quarters within 38.
Since we started tracking on Sep 25, 2026, the dates moved once, on Sep 25, 2026: primary completion Jun 2026 → Sep 2026 and completion Sep 2026 → Oct 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
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 ↗
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Universiti Kebangsaan Malaysia Medical Centre