Green tea, anti-diabetic or diabetogenic: a dose response study.
Present study was conducted to clarify whether lower or higher dietary dose of green tea is beneficial for the reduction of risk of type 2 diabetes. Five weeks old male SD rats were fed high fat diet for 2 weeks then divided into 4 groups of 8 animals as Normal Control (NC), Diabetic Control (DBC), Green Tea Low (GTL, 0.5%, Green Tea High (GTH, 2.0%) groups. Diabetes was induced by intra-peritoneal (i.p) injection of STZ (40 mg/kg BW) in all animals except NC group. After 4 weeks feeding of experimental diets, serum fasting blood glucose was not decreased but relatively increased in both green tea fed groups compared to DBC group. Serum insulin concentration was significantly (p< 0.05) increased in GTL group but not in GTH group when compared with DBC group. Serum lipids were significantly decreased in GTH group but not in GTL group compared to DBC group. Intra-peritoneal glucose tolerance test, blood HbA1c, liver weight, and liver glycogen level were not influenced by the feeding of green tea containing diets. Data of this study suggest that lower dose of green tea is insulinotropic when higher dose is hyperglycemic but hypolipidemic at least in this experimental condition.
Islam
Md Shahidul
MS
Department of Food and Nutrition, Seoul National University, Seoul 151-742, South Korea. sislam1974@yahoo.com
Choi
Haymie
H
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight / Q000187:drug effects; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005951:Glucose Tolerance Test; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013662:Tea / Q000737:chemistry*; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004041:Dietary Fats; D010936:Plant Extracts; D013662:Tea; D014280:Triglycerides; D002784:Cholesterol