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 ) .
Acute ingestion of catechin-rich green tea improves postprandial glucose status and increases serum thioredoxin concentrations in postmenopausal women.
Elevated postpr and ial hyperglycaemia and oxidative stress increase the risks of type 2 diabetes and CVD . Green tea catechin possesses antidiabetic properties and antioxidant capacity . In the present study , we examined the acute and continuous effects of ingestion of catechin-rich green tea on postpr and ial hyperglycaemia and oxidative stress in healthy postmenopausal women . Participants were r and omly assigned into the  placebo ( P , n 11 ) or green tea ( GT , n 11 ) group . The GT group consumed a catechin-rich green tea ( catechins 615 mg/350 ml ) beverage per d for 4 weeks . The P group consumed a placebo ( catechins 92 mg/350 ml ) beverage per d for 4 weeks . At baseline and after 4 weeks , participants of each group consumed their design ated beverages with breakfast and consumed lunch 3 h after breakfast . Venous blood sample s were collected in the fasted state ( 0 h ) and at 2 , 4 and 6 h after breakfast . Postpr and ial glucose concentrations were 3 % lower in the GT group than in the P group ( three-factor ANOVA , group × time interaction , P < 0·05 ) . Serum concentrations of the derivatives of reactive oxygen metabolites increased after meals ( P < 0·05 ) , but no effect of catechin-rich green tea intake was observed . Conversely , serum postpr and ial thioredoxin concentrations were 5 % higher in the GT group than in the P group ( three-factor ANOVA , group × time interaction , P < 0·05 ) . These findings indicate that an acute ingestion of catechin-rich green tea has beneficial effects on postpr and ial glucose and redox homeostasis in postmenopausal women
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 ) .