The Effects of Carbohydrates in Irritable Bowel Syndrome

Last updated: November 19, 2025
Sponsor: Sahlgrenska University Hospital
Overall Status: Completed

Phase

N/A

Condition

Colic

Bowel Dysfunction

Lactose Intolerance

Treatment

Fructan reintroduction

Placebo reintroduction

Clinical Study ID

NCT04830410
FIBS 2020-03644
  • Ages 18-50
  • All Genders

Study Summary

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.

Eligibility Criteria

Inclusion

Inclusion Criteria:

  • IBS according to ROME IV criteria (with diarrhoea)

Exclusion

Exclusion Criteria:

  • Celiac disease or any other gastroenterology disease (such as inflammatory boweldisease, celiac disease, microscopic colitis, diverticulitis, radiation enteritis).

  • Suspected or known strictures, fistulas or physiological/mechanical GI obstruction,history of gastric bezoar.

  • Appendicectomy and cholecystectomy <3 months.

  • Heart-, liver-, neurological-, or current psychiatric disease, diabetes, obesity (BMI>30), other disease or surgery to the abdomen that affected intestinal function.

  • Implantable or portable electro-mechanical medical devices, e.g. pacemakers.

  • Swallowing disorders/dysphagia to food or pills.

  • Allergy or intolerances to foods.

  • Compliance to a special diet (including vegan, vegetarian, gluten-free or low FODMAPdiet).

  • Pregnant or breast feeding.

  • Usage of antibiotics within 4 weeks prior to inclusion

  • Usage of alcohol more than 14 units per week.

  • No new pharmacological treatment during the study period.

  • Medications: laxatives, neuromodulators or opioids (morphine, codeine, tramadol…)

Study Design

Total Participants: 65
Treatment Group(s): 2
Primary Treatment: Fructan reintroduction
Phase:
Study Start date:
March 30, 2021
Estimated Completion Date:
June 02, 2025

Connect with a study center

  • Sahlgrenska University Hospital

    Gothenburg 2711537,
    Sweden

    Site Not Available

  • Sahlgrenska University Hospital

    Göteborg,
    Sweden

    Site Not Available

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