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

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.

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.