Effect of Changes in Carbohydrate Intake Patterns on Glucose Control in Patients With Type 1 Diabetes

• Main Objective: To evaluate the effect of changes of carbohydrate intake on glucose control in patients with type 1 diabetes.

• Primary endpoint: difference of time in range (TIR) between the 2 groups.
• Secondary endpoint:

• difference of coefficient of variation (CV), mean amplitude of glycemic excursions (MAGE) , large amplitude of glycemic excursions (LAGE) between the 2 groups; 2) difference of change in HbA1c，GA，1,5-anhydroglucitol (1,5-AG) from baseline between the 2 groups; 3) difference of change in incidence of hypoglycemic events (%), severe hypoglycemia and nocturnal hypoglycemia events from baseline between the 2 groups; 4) difference of change in insulin dose (IU/kg/day) from baseline between the 2 groups.

• Secondary objective: To explore the possible mechanism of dietary intervention to improve blood glucose control in patients with type 1 diabetes.

• Effects of dietary intervention on intestinal microenvironment and microflora of type 1 diabetes patients;
• Effects of dietary intervention on immune function of type 1 diabetes patients;
• Effects of dietary intervention on metabolomics of type 1 diabetes patients.

Inclusion criteria

• Those who agree to participate in the study and sign informed consent;
• Diagnosis of type 1 diabetes mellitus (ADA2024);
• Age of 18~70 years;
• Dependent on exogenous insulin therapy, the treatment plan remains unchanged within 2 months (the type of insulin cannot be changed, and the dose can be adjusted according to plasma glucose);
• Body mass index (BMI) of 18~25kg/m2;
• HbA1c ≤11%;

Exclusion criteria

• Honeymooners with type 1 diabetes mellitus;
• Women who are pregnant or plan to become pregnant;
• Patients who are vegetarians or are undergoing weight loss;
• Patients who are users of oral hypoglycemic drugs (alpha-glucosidase inhibitors, DPP-IV inhibitors, etc.);
• Patients who are users of glucocorticoids within 30 days;
• History of severe food allergy;
• Patients with acute complications such as DKA or HHS within six months;
• Patients with gastroparesis, inflammatory bowel disease and other complications;
• Patients with large albuminuria(albumin-to-creatinine ratio>34.09mg/mmol) and renal insufficiency(creatinine>200umol/L);
• Patients with uncontrolled hyperthyroidism and hypothyroidism(Uncontrolled hyperthyroidism is defined as abnormal TSH and T4. Uncontrolled hypothyroidism is defined as TSH > 10mIU/L.);
• History of heart disease, coronary heart disease and arrhythmia;
• Serious of liver dysfunction (ALT or AST>3 times the upper limit of normal);
• History of malignant tumors; History of tumors or surgeries affecting digestion and nutrient absorption; Patients with a history of benign tumors, which is judged by the physician to be not suitable;
• Patients with uncontrolled other immune system diseases or uncontrolled infections;
• Alcohol abuse, drug abuse, mental disorders or other conditions unfit to be an observer in drug tests;
• Patients with any disease likely to interfere with study participation or evaluation.