Effect of Different Carbohydrate Intake Patterns on Glycemic Control in Patients With Type 1 Diabetes

Summary

This multicenter, randomized, controlled, open-label clinical trial aims to evaluate the effects of different carbohydrate intake patterns on glycemic control in adults with type 1 diabetes. Participants will first complete a 2-week run-in period and will then be randomly assigned in a 1:1 ratio to one of two dietary groups. Both diets provide similar proportions of total energy from carbohydrates, protein, and fat, but differ in the sources of staple carbohydrates. In the moderate carbohydrate diet group, most staple foods are refined grains, whereas in the diverse carbohydrate diet group, approximately half of the staple foods are whole grains and legumes. 80 participants will follow the assigned dietary intervention for 2 weeks, followed by a 12-week follow-up period. The primary outcome is time in range (TIR), defined as the percentage of time that glucose levels are within the target range, measured using continuous glucose monitoring. Other measures of glycemic control, glycemic variability, insulin requirements, body measurements, metabolic indicators, and safety will also be evaluated. Exploratory analyses will assess potential changes in gut microbiota, immune function, and metabolomic profiles.

Eligibility

Inclusion Criteria:

1. Participants who agree to participate in the study and provide written informed consent;
2. Diagnosed with type 1 diabetes mellitus according to the ADA 2024 criteria;
3. Aged 18 to 70 years, inclusive;
4. Receiving exogenous insulin therapy with a stable treatment regimen for at least 2 months before enrollment (the type of insulin should remain unchanged, while the dose may be adjusted according to blood glucose levels);
5. Body mass index (BMI) between 18.0 and 25.0 kg/m², inclusive;
6. Glycated hemoglobin A1c (HbA1c) \<11%.

Exclusion Criteria:

1. Type 1 diabetes mellitus in the honeymoon phase;
2. Pregnant or breastfeeding women, or women for whom pregnancy cannot be ruled out;
3. Patients who are vegetarians or are undergoing weight loss;
4. Patients who are users of oral hypoglycemic drugs (alpha-glucosidase inhibitors, DPP-4 inhibitors, etc.);
5. Use of glucocorticoids within 30 days before enrollment;
6. History of severe food allergy;
7. Patients with acute complications such as diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS) within the previous 6 months;
8. Patients with gastroparesis, inflammatory bowel disease or other complications;
9. Patients with macroalbuminuria (albumin-to-creatinine ratio \> 34 mg/mmol) or renal insufficiency (creatinine \> 200 μmol/L);
10. Patients with uncontrolled hyperthyroidism or hypothyroidism (Uncontrolled hyperthyroidism is defined as abnormal TSH and FT4. Uncontrolled hypothyroidism is defined as TSH \> 10 mIU/L.);
11. History of heart disease, coronary artery disease or arrhythmia;
12. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \>3 times the upper limit of normal;
13. History of malignant tumors; history of tumors or surgery affecting digestion or nutrient absorption. Eligibility of participants with a history of benign tumors will be determined by the investigator;
14. Patients with other uncontrolled immune system diseases or uncontrolled infections;
15. Alcohol abuse, drug abuse, mental disorders, or other conditions unsuitable for study participation;
16. Any disease or condition that, in the investigator's judgment, may interfere with study participation or evaluation.

Conditions4

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