Antioxidant-rich red wine and tea could help regulate blood sugar levels in diabetics, suggests a new study from the University of Massachusetts.
Red wine and tea might inhibit the activity of alpha-glucosidase, an enzyme responsible for triggering the absorption of glucose by the small intestine according to the new laboratory study (in vitro). In addition the researchers report no effect on the activity of alpha-amylase, an enzyme responsible for starch metabolism, and an undesirable effect observed with some current medications used to control blood sugar.
The researchers took four random samples of red and white wine, and extracts from four types of tea (black, oolong, white and green teas). Laboratory tests focussed on the alpha-glucosidase enzyme, already used as a target for some current drugs used to treat type-2 diabetes, and tested the wines and tea extracts. The same concentration was also tested for alpha-amylase activity.
Results indicated that red wine inhibited alpha-glucosidase by almost 100%, while inhibition of the enzyme by white wines was only about 20%. A dose-dependent effect for the teas was observed, with black tea extracts possessing the highest level of inhibition (over 90% at a concentration of 200 micrograms per millilitre), followed by white tea and oolong tea (87% and 80%, respectively). Theresearchers concluded that these effects were related to the concentration of polyphenolics.
“The major phenolic components of red wine are caffeic acid, coumaric acid, gallic acid and quercetin, and of tea are protocatechuic acid, caffeic acid, coumaric acid and gallic acid,” stated the researchers. “These phenolic compounds were linked to high alpha-glucosidase inhibitory activity,” they added.
Small or negligible effects on alpha-amylase activity were recorded by the researchers.
“It is clear that some wine and tea types have high antioxidant activity and good inhibitory profiles on carbohydrate-modulating enzymes related to glucose absorption in the intestine,” stated the researchers. “The potential for managing both glucose absorption and cellular redox dysfunction for preventing postprandial hyperglycemia linked to type 2 diabetes and hyperglycemia-induced vascular complications leading to hypertension can be designed in part through food systems, and provides the basis for clinical studies.”
Source: Journal of Food Biochemistry Volume 32, Number 1, Pages 15-31, “Inhibitory potential of wine and tea against alpha-amylase and alpha-glucosidase for management of hyperglycemia linked to type-2 diabetes” Authors: Y.-I. Kwon, E. Apostolidis, K. Shetty