Red Wine Chemical May Treat Diabetes

CBSNEW HEALTH
Oct 14, 2009
Red Wine Chemical May Treat Diabetes
Resveratrol Lowers Blood Sugar Levels, Improves Insulin Levels in Mouse Study

(WebMD) The much touted compound resveratrol shows some promise as a future type 2 diabetes, but drinking wine or taking resveratrol supplements isn't likely to do diabetic people much good, researchers say.

Resveratrol, found in red wine, was found to lower blood sugar levels and improve insulin levels when injected directly into the brains of mice fed very high-calorie diets in a study conducted by researchers at the University of Texas Southwestern Medical Center (UTSW).

The finding suggests that the brain plays a key role in resveratrol's
beneficial effect on diabetes and that the benefits may occur independently of diet and body weight.

If this is true, new type 2 diabetes treatments targeting the brain may be possible, lead researcher Roberto Coppari, PhD, tells WebMD.

But drinking red wine is not likely to improve blood sugar and insulin
levels because resveratrol does not cross the blood-brain barrier very efficiently.

"We don't want to send the message that you can treat diabetes by drinking red wine," Coppari tells WebMD. "Two or three glasses a day wouldn't be nearly enough for the brain to accumulate the amount of resveratrol delivered in our study. It would take many, many bottles, and clearly that wouldn't be good for you."

Resveratrol: Fountain of Youth?
Resveratrol first made headlines several years ago when researchers identified it as the substance likely responsible for the health benefits to the heart attributed to red wine.

The buzz became almost deafening early this year, when the news program 60 Minutes aired a story suggesting that resveratrol-based drugs may one day succeed in slowing aging in humans.

Found mostly in the skin of red grapes and other dark fruits, resveratrol has been shown to protect against diabetes in studies involving mice, although very high doses of the molecule have been needed.

In the newly published study, Coppari and colleagues examined whether injecting resveratrol directly into the brains of diabetic mice would activate a group of proteins known as sirtuins, which have been shown to have anti-diabetes properties in earlier animal studies.

The UTSW researchers injected one group of diabetic mice with resveratrol, while a second group was given saline-containing placebo injections.

All the mice were fed a very high-fat diet throughout the study.

Despite this, insulin levels in the resveratrol-treated mice dropped
significantly and were halfway to normal by the end of the five-week study. Insulin levels among the placebo-treated mice continued to rise.

Resveratrol Activates SIRT1
The resveratrol injections were found to activate SIRT1 proteins in the brain and they reduced brain inflammation related to the mice's high-calorie diets.

The study was published this week online and it will appear in the December issue of the journal Endocrinology.

"The brain appears to be a major player in diabetes," Coppari says. "The treatments we have for diabetes target other organs like the liver. The brain hasn't really been on the map."

If the findings are confirmed, Coppari believes the brain could become a target for not only diabetes treatments, but treatments for cardiovascular disease and obesity as well.

The study is not the first to show that resveratrol can prevent the deleterious consequences of a high-fat diet. In November of 2006, researchers from Harvard Medical School and the National Institute on Aging reported that obese mice fed a diet containing 60 percent of calories from fat lived significantly longer if they were treated with resveratrol.

The resveratrol-treated mice lived as long as lean mice, with a much better quality of life, as measured by motor skills tests.

"After six months, resveratrol essentially prevented most of the negative effects of the high calorie diet in mice," study co-author Rafael de Cabo, PhD, of the National Institutes of Aging says in a news release.

Red Wine Helps Kick-Start Good Digestion

Wine Spectator
Red Wine Helps Kick-Start Good Digestion
Portuguese study finds the beverage triggers chemical reactions inside the stomach
Jacob Gaffney
Posted: October 14, 2009

Red wine not only goes well with a nice meal, it helps the stomach convert potentially harmful chemicals into less dangerous molecules before they're circulated in the body, according to a new study slated to be published in an upcoming journal of Toxicology. A team of Portuguese researchers found that specific polyphenols in red wine trigger the release of nitric oxide, a chemical that relaxes the stomach wall, helping to optimize digestion.
According to co-author Dr. João Laranjinha, an associate professor at the Center for Neurosciences and Cell Biology at the University of Coimbra, Portugal, the research bucks current theory. Since the 1990s, many researchers have believed that many of wine's observed health benefits are due to the antioxidative properties of polyphenols. Studies have found wine appears to counteract deleterious, oxidative injury to the body's molecules and cells, as with chronic, inflammatory conditions such as atherosclerosis, a condition in which fatty material collects along the walls of arteries.
Many of these studies suggest that people would need to consume impossibly large amounts of red wine in order to see any antioxidative benefit, because polyphenols are extensively metabolized during absorption in the intestines, said Laranjinha. Estimates range anywhere from a couple of bottles per day, to 10,000 per week.
But an earlier study by the same team and published in Free Radical Biology & Medicine in 2008 found that red wine's benefits may begin before it reaches the intestine. "We started to check for beneficial effects occurring before the absorption phase, that is in the stomach," said Laranjinha. "Overall, the observations of the current study suggest a new pathway for the health benefits of wine ethanol and polyphenols in humans, beyond antioxidant activity, via production of nitric oxide."
While in large doses nitric oxide is a pollutant, in smaller amounts it can dilate arteries, helping blood flow. It also has the ability to "relax" the walls of the stomach, allowing nutrients to pass more freely into the bloodstream. In the earlier study, Laranjinha and his team noted that red wine showed a higher level of another chemical, called ethyl nitrite, when compared to non-alcoholic beverages and brandy. Ethyl nitrite, they found, reacts with potentially harmful free radicals, called nitrites, by chemically converting the molecules into nitric oxide. (Nitrites are found in salty and processed meats and can react poorly in the body, forming carcinogens.)
For the current research, the Portuguese researchers used samples of various red-wine polyphenols, such as catechin, epicatechin and quercetin, which are also found abundantly in apples, berries and onions.
To test if these polyphenols reduce the levels of nitrites in the stomach, the scientists examined the combined effect on preserved rodent gastric strips and on a sample of synthetic stomach acid. After 60 minutes of being exposed to the polyphenols, the stomach strips relaxed and the acid showed high levels of ethyl nitrite.
Taking it one step further, they recruited six healthy volunteers to eat a serving of lettuce, which is known to produce nitrites in the stomach, then served them red wine. After 60 minutes the participants would regurgitate into airtight containers so the contents could be examined. The scientists also found high levels of nitric oxide in the stomach acid.
"Both major [components] of red wine, the polyphenols and the ethanol, may induce beneficial effects via production of nitric oxide," said Laranjinha. "Mechanistically, the polyphenols reduce the nitrites consumed in the diet into nitric oxide in the stomach, and the ethanol reacts with nitrite and derived species in the stomach yielding a new molecule, ethyl nitrite, that releases the nitric oxide."