Elevated blood glucose can devastate the body, causing heart disease, stroke, kidney failure, nerve damage, gangrene (especially of the feet) and blindness. And while drinking green tea has been associated with a decrease in the absorption of carbohydrate and a reduced risk of developing type 2 diabetes, it’s still uncertain whether or not tea drinking can actually lower blood glucose.
To find out, researchers gathered dietary information (including consumption of black or green tea) from 300 elderly men and women living in the Mediterranean area. They also measured their fasting blood glucose levels, body mass index (BMI) and other factors.
The results? Tea intake was associated with lower blood glucose levels, but only in non-obese people. And moderate tea consumption (1-2 cups per day) reduced the risk of having diabetes by 88%, no matter what the participant’s age, sex, dietary and exercise habits, or smoking status -- but again, only in the non-obese.
(Polychronopoulos E, Zeimbekis A, Kastorini CM, et al. Effects of black and green tea consumption on blood glucose levels in non-obese elderly men and women from Mediterranean Islands (MEDIS epidemiological study). Eur J Nutr 2008;47(1):10-6.)