Red Wine and Tea: Good for You?

Good news for red wine and tea drinkers—your favorite beverages may help control after-meal spikes in your blood glucose levels.

Researchers at the University of Massachusetts, Amherst, have published a study that looked at the effects of two types of wine and four types of tea on the activity of an enzyme, alpha-glucosidase. In the human body, alpha-glucosidase regulates the absorption of glucose by the small intestine, and blocking its action can help reduce the spike in blood glucose levels that can occur in people with diabetes after meals. (In fact, a class of drugs called alpha-glucosidase inhibitors, including Precose [acarbose] and Glyset [miglitol], does just that.)

In their study, which was published on April 3 in the Journal of Food Biochemistry, the researchers tested the effects of red wine and white wine on alpha-glucosidase in test tubes. They found that red wine inhibited the enzyme’s activity by almost 100%, while white wine inhibited it by about 20%. They also tested black, oolong, white, and green teas, and found that black tea inhibited alpha-glucosidase the most of the teas, followed by white tea and oolong tea. What’s more, neither wine nor tea affected another enzyme, pancreatic alpha-amylase, which breaks down starch. Some of the drugs that block alpha-glucosidase action can also block alpha-amylase, which can lead to uncomfortable side effects such as bloating, flatulence, and diarrhea.

The researchers believe that the helpful effects of red wine and tea are related to their high antioxidant content; in particular, to a type of antioxidant called polyphenolics, which are found in many plant-based foods. Polyphenolics may play a role in blocking alpha-glucosidase and slowing the absorption of glucose into the bloodstream. They may also fight oxidative stress in other parts of the body, helping to protect the body from diabetes complications, such as heart disease.

While this study took place in a laboratory and didn’t involve any human subjects, the researchers conclude that it should inspire further study of the use of wine and tea in managing Type 2 diabetes. They also point out that it highlights “the importance of an antioxidant-rich diet as part of an overall management strategy.”

For a more in-depth explanation of how antioxidants work in the body, please see the article “Antioxidants: Should You Supplement?”