No evidence support the consumption of GT/GTE could reduce the levels of HbA1c , HOMA-IR , fasting insulin , or fasting glucose in people with pre-diabetes/T2DM .
Green tea or green tea extract ( GT/GTE ) has been demonstrated to reduce insulin resistance and improve glycemic control .
However , evidence for this health beneficial effect is inconsistent .
This systematic review evaluated the effect of GT/GTE on insulin resistance and glycemic control in people with pre-diabetes/type 2 diabetes mellitus ( T2DM ) .
Diet supplementation with green tea extract epigallocatechin gallate prevents progression to glucose intolerance in db/db mice
Background Green tea was suggested as a therapeutic agent for the treatment of diabetes more than 70 years ago , but the mechanisms behind its antidiabetic effect remains elusive . In this work , we address this issue by feeding a green tea extract ( TEAVIGO ™ ) with a high content of epigallocatechin gallate ( EGCG ) or the thiazolidinedione PPAR-γ agonist rosiglitazone , as positive control , to db/db mice , an animal model for diabetes . Methods Young ( 7 week-old ) db/db mice were r and omized and assigned to receive diets supplemented with or without EGCG or rosiglitazone for 10 weeks . Fasting blood glucose , body weight and food intake was measured along the treatment . Glucose and insulin levels were determined during an oral glucose tolerance test after 10 weeks of treatment . Pancreata were sample d at the end of the study for blinded histomorphometric analysis . Islets were isolated and their mRNA expression analyzed by quantitative RT-PCR . Results The results show that , in db/db mice , EGCG  improves glucose tolerance and increases glucose-stimulated insulin secretion . EGCG supplementation reduces the number of pathologically changed islets of Langerhans , increases the number and the size of islets , and heightens pancreatic endocrine area . These effects occurred in parallel with a reduction in islet endoplasmic reticulum stress markers , possibly linked to the antioxidative capacity of EGCG . Conclusions This study shows that the green tea extract EGCG markedly preserves islet structure and enhances glucose tolerance in genetically diabetic mice . Dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes
No evidence support the consumption of GT/GTE could reduce the levels of HbA1c , HOMA-IR , fasting insulin , or fasting glucose in people with pre-diabetes/T2DM .
Green tea or green tea extract ( GT/GTE ) has been demonstrated to reduce insulin resistance and improve glycemic control .
However , evidence for this health beneficial effect is inconsistent .
This systematic review evaluated the effect of GT/GTE on insulin resistance and glycemic control in people with pre-diabetes/type 2 diabetes mellitus ( T2DM ) .