Red wine and tea may help type 2 diabetes patients metabolize sugars and starches properly, according to research published in the February 2008 issue of Journal of Food Biochemistry. But the study's authors warn that more research is necessary before prescribing a bottle and kettle a day.
People who live with type 2 diabetes must keep blood sugar levels as normal as possible to prevent the disease from elevating the chances of heart disease, high blood pressure and possible damage to eyes, kidneys, nerves and blood vessels. "Levels of blood sugar, or blood glucose, rise sharply in patients with type 2 diabetes immediately following a meal," said researcher Kalidas Shetty, a professor of food biotechnology at the University of Massachusetts, Amherst, and a U.S. State Department Jefferson Science Fellow. "Red wine and tea contain natural [phenolic] antioxidants that may slow the passage of glucose through the small intestine and eventually into the bloodstream and prevent this spike."
Shetty and his team at the department of food science conducted the study as part of a larger initiative to examine the benefits of a diverse diet filled with fresh and healthy, locally available ingredients. Current type 2 diabetes medication to regulate blood sugar has side effects that include intestinal issues. The medication induces improper regulation of pancreatic enzymes, which may cause cramping, flatulence and diarrhea. Shetty and fellow scientists Young-In Kwon and Emmanouil Apostolidis said that alternative therapies, such as dietary management, may offer a solution with no uncomfortable side effects.
Diets rich in red wine have already shown established benefits to heart health. The "Mediterranean diet," rich in wine and fruit, has been shown to protect against heart attacks. Likewise, research on tea has shown beneficial effects on health. Both are rich in phenols, plant-based chemicals that have been found in previous studies to prevent cardiovascular disease. The chemicals also act as antioxidants, which help reduce the damaging oxidative stress on human tissues prevalent in type 2 diabetes.
The scientists prepared samples of two enzymes. The first enzyme alpha-glucosidase, is responsible for triggering the absorption of glucose by the small intestine. In type 2 diabetes sufferers, alpha-glucosidase causes too much starch and sugar to be broken down in the small intestine, thus flooding the blood with too much sugar. The second enzyme, called alpha-amylase, is often triggered by type 2 diabetes medications, causing the painful side effects.
After preparing the enzymes, the scientists exposed the samples to four types of tea: green, black, oolong and white, as well as eight kinds of wine: four reds and four whites, all sourced from local liquor stores. When the scientists exposed the enzymes separately to the teas and wines, they found all of the red wines were able to inhibit the enzyme alpha-glucosidase by nearly 100 percent, which meant better blood-sugar regulation. The white wines were only able to inhibit the glucose-digesting molecule by 20 percent. All of the teas inhibited alpha-glucosidase by 85 to 95 percent. Shetty added that the differences between red and white wines came as no surprise given the levels of phenols in red is considerable higher.
Furthermore, neither the wine nor the tea triggered the pancreatic enzyme, alpha-amylase, which means the beverages may potentially prevent the painful side effects.
In spite of this, Shetty warns that red wine as a type 2 diabetes therapy is still in the distant future as it is difficult to create a daily dosage recommendation for the general population based on one study. "I would not suggest drinking red wine to solve a problem all on its own," he said. "I would suggest one to two glasses [of red wine daily] plus four to five glasses of tea and a range of choices of whole foods," in order to consume optimal levels of phenols.
"We feel the best approach is to have sufficient local food and traditional food diversity, and especially whole and fresh foods, that can provide incremental doses of these protective phenolic chemicals," he said.