The Effects of Raspberry Leaf Tea on Blood Glucose Control

The volunteer inclusion criteria are: (Fasting blood glucose in the range \< 5.5 mmol/l (at day 0); A signed consent form; Age 18-65 years; Body mass index ≤ 34.9 kg/m2; Non-smoking; No pregnancy/lactation; No use of herbal medicines for at least the previous three months; Not on a weight loss program six months before screening; Not involved in clinical trial six months before screening; Not had severe cardiac, hepatic, or renal function impairment). The volunteer exclusion criteria are: (Smoking, Pregnancy/lactation; Use of herbal medicines for at least the previous three months; Involved in a weight loss program six months before screening; Involved in clinical trial six months before the screening; Had severe cardiac, hepatic, or renal function impairment; Sufferers of chronic illnesses; Individuals with food allergies; People with prediabetes or diabetes; People with coeliac disease) If all subjects are generally healthy, as demonstrated by their medical history and laboratory tests, including fasting blood sugar and insulin levels, as well as HOMA-IR, liver function tests (alanine transaminase, alkaline phosphatase, total bilirubin, and gamma-GT), renal function tests (uric acid and creatinine), and lipid profile tests (total cholesterol, Triglycerides). They will be asked to attend a four-study visit after an eight-hour overnight fast. Volunteers will be asked to consume 50 g of carbohydrate powder (sucrose and glucose) with or without 10 g of raspberry leaf tea, which will be dissolved in 300 mL of warm water during four visits (every month). Blood samples will be taken at intervals for a period of two hours after the consumption of raspberry leaf or control. Blood glucose and insulin levels will be tested 15 minutes before, at 15,30,60,90, and 120 minutes after carbohydrate intake.