Food and their components are often reported as gastrointestinal (GI) symptom triggers in patients with IBS. The current interest in dietary management in IBS, has largely focused on the negative effect of poorly absorbed and subsequently fermented carbohydrates (FODMAP - Fermentable Oligo-, Di-, Mono-saccharides And Polyols). These unabsorbed carbohydrates can generate GI symptoms through osmosis, with increased amount of fluid in the gut lumen, and via modification of gut microbiota composition and function (fermentation and production of gas). Studies assessing diets low in FODMAPs have shown promising results in symptom improvement in some IBS patients, but not in all. The low FODMAP diet, as it is used today, is restrictive and difficult for patients to accommodate in their daily life. Moreover, the effect of this diet on microbiota composition and function is not defined, and there are also concerns that restrictive diets may lead to nutritional inadequacy. Fructan is a specific FODMAP which is built of fructose polymers. Examples of foods that contain fructans are wheat, onion, garlic and banana. The daily dietary intake of fructans varies approximately between 3 and 6 grams. Fructans are potential triggers of GI symptoms in IBS however, they are currently also used as prebiotic supplements. A recent systematic review and meta-analysis concluded that low dosages of fructans do not worsen GI symptoms, but they do increase the beneficial bifidobacteria. It remains unclear whether the potential benefits of fructans outweigh the potential harmful effects in patients with IBS. The investigators are aiming to assess the effects of fructans, as well as predictive factors and mechanisms involved, and to compare with placebo in IBS patients. The investigators will assess GI symptom severity, visceral sensitivity, intestinal gas production, gut immunity and microbiota, and metabolites produced in the gut.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
65
Patients will reintroduce fructan powder after 14-day of a low FODMAP diet
Patients will reintroduce placebo powder after 14-day of a low FODMAP diet
Sahlgrenska University Hospital
Gothenburg, Sweden
IBS-SSS
change in irritable bowel syndrome severity scoring system (IBS-SSS) between the 2 groups. IBS-SSS is between 0 and 500, with a higher score meaning more severe symptoms.
Time frame: before and after the reintroduction (7days +/-3 days)
visceral sensitivity
measured by a rectal barostat, predictor for a better GI response to a low FODMAP diet and predictor of a worse GI response to fructan reintroduction
Time frame: Baseline
change in intestinal gas production
measured by a gas sensing capsule (Atmo), between the 2 groups
Time frame: between baseline and after (7days +/-3 days) of reintroduction
change in gas production
measured by breath tests (H2 and CH4) between the 2 groups.
Time frame: between baseline and after (7days +/-3 days) of reintroduction
change in microbiota
Fecal microbiota analysis using 16S technique between the 2 groups.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
Change in metabolomics profiles
Targeted and untargeted metabolomics in urine, blood and stool samples measured by Liquid and gas chromatography-mass spectrometry between the 2 groups.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
change in stool form and frequency
Stool diary between the 2 groups.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
GSRS-IBS
change in Gastrointestinal symptom rating scale-IBS (GSRS-IBS) between the 2 groups. GSRS-IBS assesses five GI symptom domains: satiety, abdominal pain, diarrhea, constipation and bloating. The five domains are calculated using the mean of two to four items scored with 7-point Likert scales, with higher scores representing more severe symptoms.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
HAD
change in Hospital Anxiety and depression scale (HAD) between the 2 groups. HAD assesses the severity of psychological distress, i.e. anxiety and depression. In this 14-item scale, seven items measure anxiety and the other seven measure depression on a 4-point Likert scale (0-3) which provides a score between 0 (absence) and 21 (high level). Scores higher than 10 on each of the subscales is considered to define clinically relevant anxiety and/or depression.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
VSI
change in Visceral sensitivity index (VSI) between the 2 groups. VSI is a 15-item validated scale measuring GI symptom-specific anxiety, i.e. the cognitive, affective, and behavioural response to fear of GI sensations, symptoms, and the context in which these occur. The total score ranges between 0 (no GI-specific anxiety) to 75 (severe GI-specific anxiety).
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
IBSQOL
change in irritable bowel syndrome quality of life (IBSQOL) questionnaire between the 2 groups. IBSQOL is a disease-specific, self-administered questionnaire, with 30 items measuring nine aspects of health-related quality of life during the past four weeks. The nine domains are emotional health, mental health, sleep, energy, physical functioning, food/diet, social role, physical role and sexual relations. Each question has five or six response options. For each subscale, the score is transformed to a 0-100 scale. A higher score represents a better quality of life.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
PHQ12
change in patient health questionnaire 12 (PHQ12) between the 2 groups. The PHQ-15 is a somatic symptom subscale derived from the full PHQ. It inquires about 15 somatic symptoms; each individual symptom is coded as 0, 1, or 2, and the total score ranges from 0 to 30, with higher scores representing more severe symptoms.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
CSI
change in Central Sensitization Inventory (CSI) between the 2 groups. The responses were graded on a Likert scale from 0 (never) to 4 (always). The total score ranges from 0 to 100. A higher score suggest higher central sensitization syndrome.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
IBS-SSS
change in irritable bowel syndrome severity scoring system (IBS-SSS) between the 2 groups.
Time frame: between baseline, after the low FODMAP diet (14 days) and after reintroduction (7+/-3 days)
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