Sucrase-Isomaltase (SI) Genes and Meal Load (SI IBS)

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

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?

Study Overview

• Status: Recruiting
• Conditions: IBS - Irritable Bowel Syndrome; Sucrase-Isomaltase Deficiency
• Intervention / Treatment: Dietary supplement: Meal load

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 70
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Bodil Ohlsson C Professor, MD, PhD; Phone Number: +46+402712660; Email: bodil.ohlsson@med.lu.se
• Study Contact Backup: Name: Mauro D'Amato Professor; Email: mdamato@cicbiogune.es

Study Locations

• Sweden
  • Skåne County
    • Malmo, Skåne County, Sweden, 20502
      • Recruiting
      • Skåne University Hospital
      • Contact: Bodil Ohlsson, Professor, MD, PhD; Phone Number: +46402712660; Email: bodil.ohlsson@med.lu.se
      • Contact: Cecilia Kennbäck, Nurse; Email: cecilia.kennback@skane.se

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Meal intake	Dietary supplement: Meal load; Meal load during 15 minutes

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes of blood glucose after a meal intake	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.	2 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes of gastrointestinal and extraintestinal symptoms after a meal intake assesssed by self-reported completion on visual analog scales	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).	2 hours

Collaborators and Investigators

• Sponsor: Region Skane
• Collaborators: Region Skåne FoUU
• Investigators: Study Chair: Cecilia Kennbäck, Registered Nurse, Department of Internal Medicine, Skåne University Hospital, 20502 Malmö

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2026
• Primary Completion (Estimated): February 1, 2028
• Study Completion (Estimated): February 1, 2030

Study Registration Dates

• First Submitted: December 2, 2025
• First Submitted That Met QC Criteria: December 15, 2025
• First Posted (Actual): December 30, 2025

Study Record Updates

• Last Update Posted (Actual): April 29, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: IBS; bowel symptoms; blood glucose levels; SI genes; Starch and sucrose
• Additional Relevant MeSH Terms: Intestinal Diseases; Digestive System Diseases; Gastrointestinal Diseases; Colonic Diseases; Colonic Diseases, Functional; Irritable Bowel Syndrome; Sucrase-isomaltase deficiency, congenital
• Other Study ID Numbers: 2025-07563-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Due to ethical rules in Sweden, we can not share individual data. The participants have written an informed concent that data will be presented group wise.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No