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NCT Number: NCT07309601

Sucrase-Isomaltase (SI) Genes and Meal Load

The goal of this interventional study is to examine whether those patients with irritable bowel syndrome (IBS) and a reduced abitility do degrade starch and sugar (lowe levels of enzymes) have lower raise in blood glucose after a meal than those with normal expression of enzymes. We also want to examine whether those IBS patients with reduced enzyme levels have increased bowel symptom in relation to this meal.

The main questions it aims to answer are:

Does reduced ability to degrade starch and sugar due to less enzyme activity lead to lower increase in blood glucose after a meal? Does reduced ability to degrade starch and sugar due to less enzyme activity lead to increased bowel symptoms after a meal?

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Key information

Conditions

IBS - Irritable Bowel Syndrome Colonic Diseases Colonic Diseases, Functional Digestive System Diseases Gastrointestinal Diseases Intestinal Diseases Irritable Bowel Syndrome Sucrase-Isomaltase Deficiency Sucrase-isomaltase deficiency, congenital

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

All IBS patients who have been included in the previous studies (Dnr 2017/171, Dnr 2021-05407-01 and Dnr 2023-01377-01) and have been genetically tested for the sucrase-isomaltse enzyme (SI gene) and other genes encoding enzymes important for carbohydrate absorption will be called and asked if they want to participate in the present study.

The patient receives a basic questionnaire about lifestyle, health and symptoms over the past 2 weeks, including Rome IV questionnaire, irritable bowel syndrome-severity scoring system (IBS-SSS), and visual analog scale for irritable bowel syndrome (VAS-IBS) to be completed at home and brought to the test. The patient comes to the clinic fasting (only allowed to drink water at home in the morning). A plastic tube is placed in the arm, and the patient has to eat a sugar-rich meal during 15 minutes. Blood samples are drawn 10 minutes before start, at the start of the meal, and 10, 20, 30, 45, 60, 90, och 120 minutes aftrewards. Blood samples are analyzed for glucose levels in blood at the Department of Clinical Chemistry, at the hospital. At the same time points as blood sampling, the patient has to complete a questionnaire about bowel symptoms.

Raise in blood glucose and bowel symptoms will be compared between those with reduced enzyme activity and those with normal enzyme activity. The correlation between blood glucose levels and symptoms will be calculated.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Diagnosis of irritable bowel syndrome (IBS)
  • Gene testing has been conducted regarding genes regulating the production of sucrase-isomaltase ensymes in previous dietary interventions using the starch- and sucrose reduced diet (SSRD) or multi-center study.

Exclusion criteria

  • Diagnosis of inflammatory bowel disease, celiac disease, bile salt malabsorption, gastroenteritis or enteric dysmotility
  • Severe food allergy
  • Serious heart-, lung-, cardiovascular-, malignant- or mental illness
  • Ongoing eating disorder
  • Pregnancy
  • Recent major gastrointestinal surgery
  • Alcohol and/or drug addiction

Treatment and study plan

Meal load

Dietary Supplement

Meal load during 15 minutes

Primary outcomes

  1. Changes of blood glucose after a meal intake

    Time frame: 2 hours

    We will measure blood glucose levels in plasma through a plastic tube. Two samples will be collected before the meal start. One sample 10 minutes before the meal intake and one immediately prior the meal intake. The meal consists of a sugar-rich breakfast, which must be ingested within 15 minutes. Blood samples will then be collected at 10, 20, 30, 45, 60, 90, and 120 minutes afterwards. Blood glucose will be measured at the Department of Clinical Chemistry at the hospital, according to clinical routines.

Secondary outcomes

  1. Changes of gastrointestinal and extraintestinal symptoms after a meal intake assesssed by self-reported completion on visual analog scales

    Time frame: 2 hours

    The assessment of changes of gastrointestinal and extraintestinal symptoms will be registered during the breakfast meal. The degree of the symptoms abdominal pain; diarrhea; constipation; bloating/flatulence; vomiting/nausea; belching/excess wind; reflux; headache; back pain; muscle/joint pain; and fatigue will be rated by the participants on 100 mm visual analg scales (VAS); one scale for each symptom. 0 mm means no symptoms and 100 means maximal symptoms. The symptoms will be registered at the same tima as the blood samples will be collected. Thus, participants have to register the symptoms 10 minutes before the meal intake, immediately prior the meal intake, and then 10, 20, 30, 45, 60, 90, and 120 minutes afterwards. These VAS scales are extracted from the validated questionnaires the irritable bowel syndrome-severity symptom score (IBS-SSS) and the visual analg scale for irritable bowel syndrome (VAS-IBS).

Study contacts

Contact information is provided by the study sponsor or research team.

Bodil Ohlsson C Professor, MD, PhD

CONTACT

[email protected]

+46+402712660

Mauro D'Amato Professor

CONTACT

[email protected]

Sponsors and collaborators

Lead sponsor

Region Skane

Other

Registry information

Official study title

Comparison of a Meal Load Between Normal and Functional Variants of the Sucrase-isomaltase (SI) Gene in IBS

Acronym: SI IBS

Important dates

Study start
2026
Primary completion
2028
Study completion
2030
First posted
Dec 30, 2025
Registry last updated
Apr 29, 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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