This is a single-arm study to investigate the heterogeneity of glycemic response to Lactobacillus paracasei LC19 in patients with newly diagnosed type 2 diabetes. Participants will receive LC19 for 12 weeks, and changes in glycemic control will be evaluated.

This is a single-center, open-label, single-arm study designed to investigate inter-individual variability in glycemic response to Lactobacillus paracasei LC19 (LC19) in patients with newly diagnosed type 2 diabetes (T2D). A total of 70 eligible participants with newly diagnosed T2DM will be enrolled. All participants will receive oral LC19 strain powder (2 packets per day, 2 g per packet) for 12 weeks. No placebo or active comparator will be included in this study.

Inclusion Criteria:

• Age 18-65 years, both genders eligible
• Drug-naive patients with newly diagnosed type 2 diabetes
• Subjects with screening HbA1c ≥ 7.0% and ≤ 9.0%
• Subjects understand the nature, significance, potential benefits, inconvenience, and risks and procedure of the study, and voluntarily sign the informed consent form

Exclusion Criteria:

• Other types of diabetes except T2D: type 1 diabetes (including adult latent autoimmune diabetes), special type diabetes, or secondary diabetes (such as acromegaly or Cushing's syndrome, etc.)
• Subjects with acute diabetic complications such as diabetic ketoacidosis or diabetic hyperosmolar coma in the past 6 months
• Subjects with history of hypoglycemia in the past 6 months
• Subjects with history of New York Heart Association class (NYHA) grade of heart function ≥ III or serious cardiovascular diseases (myocardial infarction, or with the history of cardiac interventional therapy or stent implantation, valve disease or valve repair, unstable angina, transient ischemic attack or stroke) within 6 months before the screening period
• Subjects with history of chronic active hepatitis and/or severe liver dysfunction, renal dysfunction, and thyroid dysfunction
• Subjects with a medical history of malignant tumor
• Subjects with history of gastrointestinal diseases that affect food digestion and absorption (such as severe diarrhea, constipation, irritable bowel syndrome, inflammatory bowel disease, active gastrointestinal ulcers, acute cholecystitis, etc.) or with a history of intestinal resection or other gastrointestinal surgery (such as cholecystectomy) within one year before the screening period
• Subjects with history of surgery, or severe trauma in the past 6 months, or planning to undergo surgery during the study period
• Subjects suffering from severe infections, severe anemia, or neutropenia
• Subjects pregnant or in lactation, or those planning to become pregnant or impregnate during or within 3 months after the study period
• Subjects with history of receiving immunosuppressants, steroids, anti diarrheal drugs, antibiotics, lipid-lowering drugs, or other gastrointestinal motility medications within the past 3 months
• Subjects using other medications that can affect blood glucose in the past 3 months
• Subjects with consumption of other probiotic or prebiotic products in the past 3 months before secreening
• Subjects with lactose intolerance, known or suspected allergy to probiotics used in experiments, history of drug allergies or allergic diseases
• Subjects with weight fluctuations ≥ 5kg in the past 3 months or planning to take medication to control weight during the study period
• Subjects with history of mental illness or epilepsy, or taking antidepressant medications
• Subjects with history of alcohol abuse (for men, alcohol consumption exceeding 40 grams per day and for women, exceeding 20 grams per day)
• Subjects have participated in any other clinical study in the past 3 months