British researchers say compounds in red wine inhibit the production of a substance called endothelin-1, which is critical to the development of heart disease. They believe the interaction may help explain the famous "French Paradox" the low incidence of coronary heart disease in red wine-drinking French populations that consume rich, fatty foods.
But a U.S. expert who co-wrote the American Heart Association's scientific advisory on wine and heart health says that as pleasant as a glass of red wine may be, a healthy diet and exercise work far better to improve your heart health.
Coronary heart disease, or the narrowing of the arteries that bring blood to the heart, affects roughly 7 million Americans, and heart attacks caused by the condition claim 500,000 lives every year.
"There has been speculation for a long time that red wine protects against heart disease, but no real mechanism had been put forward," said lead study author Roger Corder, a professor of experimental therapeutics at Barts & The London School of Medicine and Dentistry, in London.
Corder and his colleagues thought that if red wine were truly protective, it should inhibit a key element in the process that leads to hardening of the arteries. "Recent evidence shows that endothelin is one of those key factors," said Corder.
"If you have high endothelin, then you get more rapid hardening of the arteries in experimental models," said Corder. Patients with heart disease have high endothelin levels both in their blood and in the walls of their blood vessels. Therapies that block endothelin dilate blood vessels and improve blood flow, he said.
In a laboratory experiment, the researchers found that polyphenol compounds in red wine made from cabernet sauvignon grapes reduced endothelin-1 production in blood vessel cells cultured from cows.
A second test compared alcohol-free extracts from 23 red wines, four white wines, one ros and one red grape juice. "Ros made from cabernet sauvignon grapes had no activity at all, and white wine was completely inactive as well," said Corder.
The red grape juice extract had an inhibiting effect, but it was much weaker than the red wine extract. The researchers say this suggests that the effect is somehow derived from the skins or other components of red grapes.
"We imagine that, given the potency that we've seen, that it would only take one to two glasses of wine per day to have sufficient polyphenol intake to have an effect on endothelin production in the vascular wall," said Corder. "As a result, heart disease would be reduced."
"For your average person in the street, it might be something that they would want to include in a health-conscious diet," said Corder.
But Dr. Ira Goldberg, the chief of preventive medicine and nutrition at Columbia University, in New York City, is concerned that the public might see red wine as a healthy way to prevent heart disease.
"The wine idea, as joyful as it might be, is basically an epidemiological association with some tissue culture data," said Goldberg. Although palatable, he said it's not a serious way to improve heart health.
While he drinks red wine himself, he said, "I'm not drinking the wine because I think it's going to protect me against a heart attack."
"There are some well-documented ways to decrease cardiovascular disease. The ways to do that are to exercise, to lower your blood pressure if it's elevated, and to lower your cholesterol," said Goldberg.
He says the other half of the so-called "paradox" is that Japan, the country that consumes the least red wine, has the lowest incidence of heart disease. "There's clearly something else that the Japanese are doing. They have very low cholesterol levels. They don't get obese. They eat a lot of fish," said Goldberg.
Corder says further research could more precisely identify the mechanism of red wine's effect on endothelin-1 and could lead to treatments that don't require patients to drink red wine.
He says while commercially available polyphenol extracts may have protective effects, their safety and effectiveness have not yet been fully studied.
The researchers hope to move on to studies of whether moderate red wine consumption reduces endothelin-1 production in humans. Several people already have volunteered for the study, said Corder.
What to do
Consuming a moderate amount of red wine with food is safe for the average person, said Corder, but he stresses that some people with certain conditions, such as cirrhosis of the liver, are more vulnerable to the effects of alcohol.
The American Heart Association publishes information on alcohol, wine and cardiovascular disease.
You also can check information on heart disease from the Wine Institute or read an overview of red wine and heart health research from the Hong Kong Academy of Medicine.
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