Red wine has been shown to protect people from heart disease, even when they follow a diet high in saturated fat, and the healing powers of tea are becoming the stuff of legend.
Now, researchers at the University of Massachusetts Amherst have shown that certain antioxidants found in red wine and tea may help regulate the blood sugar of people with type 2 diabetes by inhibiting the action of alpha-glucosidase that controls the absorption of glucose from the small intestine, and protect the body from complications such as high blood pressure and heart disease.
"Levels of blood sugar, or blood glucose, rise sharply in patients with type 2 diabetes immediately following a meal. Red wine and tea contain natural antioxidants that may slow the passage of glucose through the small intestine and eventually into the bloodstream and prevent this spike, which is an important step in managing this disease," said Kalidas Shetty, a food scientist at the University of Massachusetts.
For the study, both red and white wines were tested in the laboratory using in vitro enzyme studies to determine how well they could stall the activity of a target enzyme called alpha-glucosidase, responsible for triggering the absorption of glucose by the small intestine.
The researchers found that red wine was the winner, and was able to inhibit the enzyme by nearly 100 percent. Values for white wine hovered around 20 percent.
This was clearly related to the amount of a specific type of antioxidants, called polyphenolics, found in the wines, Shetty said.
"Our testing showed that red wine contains roughly ten times more polyphenolics than white wine. Laboratory results suggest that these compounds, found in many plant-based foods, may play a role in inhibiting alpha-glucosidase and slowing the passage of carbohydrates into the bloodstream," he added.
Alpha-glucosidase is the target for current drugs used to treat type 2 diabetes and the development of new drugs.
The team also tested four kinds of tea, including black, oolong, white and green teas. Water extracts of black tea had the highest effect on inhibiting the activity of alpha-glucosidase, followed by white tea and oolong tea.
Wine and tea had no effect on a pancreatic enzyme called alpha-amylase that breaks down starch, which could help patients avoid the side effects of medications used to control blood sugar.
"A major drawback of medications that control both enzymes is the bacterial fermentation of undigested carbohydrates, especially starch, in the colon, which can lead to side effects such as flatulence, bloating and diarrhea," said Shetty.
"Tea and wine had no effect on the breakdown of starch by alpha-amylase, which could potentially help patients avoid these side effects," he added.
Another benefit is that the polyphenolics in wine and tea could also help in protecting the rest of the body from the additional complications of diabetes such as high blood pressure and heart disease.
"These results provide strong evidence for further studying the use of wine and tea to manage some stages of type 2 diabetes using animal models and clinical studies, and point to the importance of an antioxidant-rich diet as part of an overall management strategy," said Shetty.
"This concept is not new, but we are finding clear cellular targets for the functions of dietary polyphenolics. Using specific beverage combinations could generate a whole food profile that has the potential to manage type 2 diabetes and its complications, especially in the early stages," he added.
The study is published in the Journal of Food Biochemistry.