Effect of a Probiotic Supplement on Gut Microbiota and Glycemic Control in Patients With Type 1 Diabetes (PRODIAB)

Not Applicable

Not yet recruiting

• Conditions: Diabete Type 1

• Registration Number: NCT07062224
• Lead Sponsor: Universidad Católica San Antonio de Murcia

Brief Summary

This randomized, double-blind clinical trial aims to evaluate the effect of a probiotic supplement on gut microbiota composition and glycemic control in adults with type 1 diabetes mellitus. A secondary comparison will be made with a healthy control group. Participants will be assigned to receive either a probiotic or a placebo for 98 days. Stool samples and metabolic parameters will be collected at baseline and after the intervention period. The study seeks to better understand how modulation of the intestinal microbiota may influence glucose regulation in people with type 1 diabetes.

Detailed Description

This randomized, double-blind clinical trial aims to evaluate the impact of a nutritional supplement composed of inulin (prebiotic) and tyndallized probiotics (paraprobiotics) on gut microbiota composition, intestinal barrier integrity, and glycemic control in individuals with type 1 diabetes mellitus (T1D). A total of 80 participants will be recruited: 40 with T1D and 40 healthy controls. Each group will be randomly assigned to receive either the active supplement or a placebo for a period of approximately 98 days.

The study will include pre- and post-intervention assessments using stool samples (for microbiota analysis and intestinal inflammation markers like zonulin and calprotectin), continuous glucose monitor (CGM) data, blood tests (for glycemic, hepatic, renal, and lipid profiles), body composition analysis by bioimpedance (including phase angle), and validated questionnaires assessing gastrointestinal symptoms, lifestyle, dietary intake, and diabetes-related quality of life.

The main objectives are to analyze changes in gut microbiota diversity and composition, assess effects on intestinal permeability and inflammation, evaluate the safety and tolerability of the supplement, and determine its impact on metabolic markers such as fasting glucose, HbA1c, glycemic variability, and HOMA-IR.

This project seeks to explore microbiota modulation as a potential complementary therapeutic strategy for improving glycemic control and metabolic health in individuals with T1D. The supplement will be provided in 10 mL gel sticks, containing 4000 mg of inulin and 1000 mg of tyndallized probiotics, taken once daily. The intervention period has been strategically planned to avoid holidays and vacation times to ensure adherence and minimize lifestyle variability.

Study Timeline

• Status Verified: 2025-07
• Study First Submitted: 2025-07-02
• Study First Submitted QC: 2025-07-02
• Last Update Submitted: 2025-07-02
• Study First Posted: 2025-07-14
• Last Update Posted: 2025-07-14
• Study Start: 2025-09-01
• Primary Completion: 2025-11
• Study Completion: 2025-12-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 80

Inclusion Criteria

• Age between 18 and 65 years.
• Ability to understand and sign the informed consent form.
• For the patient group: diagnosis of type 1 diabetes with at least 1 year of disease progression.
• For the control group: healthy individuals without a diagnosis of diabetes or other metabolic disorders.
• No use of antibiotics, probiotics, or prebiotics during the 4 weeks prior to the study start.
• Willingness to comply with the study protocol and attend scheduled visits.

Exclusion Criteria

• Current use of probiotics, prebiotics, or antibiotics.
• Chronic gastrointestinal diseases (e.g., inflammatory bowel disease, irritable bowel syndrome).
• Pregnancy or breastfeeding.
• Participation in another clinical trial within the past 3 months.
• Immunosuppressive diseases, active cancer, or treatment with immunosuppressants.
• Known allergy or intolerance to any component of the supplement or placebo.
• Excessive alcohol or drug use.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: FACTORIAL

Primary Outcome Measures

Name	Time	Method
Change in gut microbiota composition	Baseline and 98 days post-intervention	Variation in the relative abundance and diversity of gut microbiota species assessed by 16S rRNA sequencing from stool samples collected at baseline and after 98 days of intervention.

Secondary Outcome Measures

Name	Time	Method
Change in fasting glucose [Time Frame: Day 1 and Day 98]	Baseline and 98 days post-intervention	Assessment of changes in fasting glucose levels (mg/dL) via blood test.
Change in HbA1c [Time Frame: Day 1 and Day 98]	Baseline and 98 days post-intervention	Assessment of changes in glycated hemoglobin levels (HbA1c, %) via blood test.
Change in fasting insulin [Time Frame: Day 1 and Day 98]	Baseline and 98 days post-intervention	Assessment of changes in fasting insulin levels via blood test. μU/mL
Change in HOMA-IR index [Time Frame: Day 1 and Day 98]	Baseline and 98 days post-intervention	Assessment of changes in insulin resistance estimated using the HOMA-IR index.
Change in time in range (70-180 mg/dL) [Time Frame: 3 months]	Baseline and 98 days post-intervention	Assessment of the percentage of time that glucose levels are within the target range using continuous glucose monitoring (CGM).
Change in time above range (>180 mg/dL) [Time Frame: 3 months]	Baseline and 98 days post-intervention	Assessment of the percentage of time with hyperglycemia using CGM.
Change in time below range (<70 mg/dL) [Time Frame: 3 months]	Baseline and 98 days post-intervention	Assessment of the percentage of time with hypoglycemia using CGM.
Change in mean glucose [Time Frame: 3 months]	Baseline and 98 days post-intervention	Assessment of average glucose concentration (mg/dL) using CGM.
Change in glucose variability [Time Frame: 3 months]	Baseline and 98 days post-intervention	Assessment of glucose coefficient of variation (%) using CGM.
Change in plasma zonulin levels [Time Frame: Day 1 and Day 98]	Baseline and 98 days post-intervention	Zonulin levels will be measured in fasting plasma samples using ELISA at baseline and after the intervention (ng/mL).
Change in fecal calprotectin levels [Time Frame: Day 1 and Day 98]	Baseline and 98 days post-intervention	Calprotectin levels will be measured in stool samples using immunoassay at baseline and after the intervention (µg/g).

Trial Locations

Locations (1)

UCAM San Antonio Catholic University of Murcia; 🇪🇸 Murcia, Spain