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 ) .
Effect of cocoa and green tea on biomarkers of glucose regulation, oxidative stress, inflammation and hemostasis in obese adults at risk for insulin resistance
Background / Objectives : Flavanols may provide protection against insulin resistance , but little is known about the amounts and types of flavanols that may be efficacious . Subjects/ Methods : This study was design ed to determine whether cocoa flavanols , over a range of intakes , improve biomarkers of glucose regulation , inflammation and hemostasis in obese adults at risk for insulin resistance . As an adjunct , green tea and cocoa flavanols were compared for their ability to modulate these biomarkers . In a r and omized crossover design , 20 adults consumed a controlled diet for 5 days along with four cocoa beverages containing 30–900 mg flavanol per day , or tea matched to a cocoa beverage for monomeric flavanol content . Results : Cocoa beverages produced no significant changes in glucose , insulin , total area under the concentration – time curve ( AUC ) for glucose or total insulin AUC . As the dose of cocoa flavanols increased , total 8-isoprostane concentrations were lowered ( linear contrast , P=0.02 ) , as were C-reactive protein ( CRP ) concentrations ( linear contrast , P=0.01 ) . The relationship between cocoa flavanol levels and interleukin-6 ( IL-6 ) concentrations was quadratic , suggesting that a maximum effective dose was achieved ( quadratic contrast , P=0.01 ) . There were no significant effects on measured indices of glucose regulation , nor on those of total 8-isoprostane , CRP and IL-6 concentrations , when cocoa and green tea were compared . However , relative to cocoa , green tea  lowered fibrinogen concentrations ( P=0.0003 ) . Conclusions : Short-term intake of cocoa and green tea flavanols does not appear to improve glucose metabolism ; they do affect selected markers of one or more measures of oxidative stress , inflammation or hemostasis in obese adults at risk for insulin resistance
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 ) .