Tea and Glucose

Black tea is rich in polyphenols as are berries. One recent study concluded, "The consumption of black tea containing BTPP (an abreviation for black tea polyphenols) can decrease postprandial blood glucose (rises in glucose afer a meal) after sucrose intake in both normal subjects and pre-diabetes subjects, suggesting that black tea may be a promising anti-diabetic agent for glycemic control."

Reference:

Bumrungpert, Akkarach, Black tea consumption improves postprandial glycemic control in normal and pre-diabetic subjects: a randomized, double-blind, placebo-controlled crossover study, Asia Pac J Clin Nutr 2017;26(1):59-64