- Coronary heart disease (CHD) is the single largest killer of U.S. males and females.
- CHD is caused by partial or complete clogging of the coronary arteries that nourish the heart.
- Atherosclerosis refers to the accumulation of fatty streak lesions in the coronary arteries.
- A recent study has found that moderate consumption of alcohol seems to inhibit the development of atherosclerotic lesions as well as inhibit the progression of existing lesions.
- In some cases, alcohol appears to have protective properties against heart disease.
"Even though the French eat a lot more cholesterol than we do," said Eugene E. Emeson, professor of pathology at the University of Illinois at Chicago College of Medicine, "they have less heart disease than we do. It was once thought this was because they drink a lot of red wine." Emeson, lead author of a study in the September issue of Alcoholism: Clinical & Experimental Research (ACER), was explaining what is popularly known as the "French Paradox." Emeson said that while there may indeed be protective properties in the products of red and white grapes, he and his colleagues found that the alcohol itself also has protective properties against heart disease.
Coronary heart disease (CHD) is the single largest killer of U.S. males and females, according to the American Heart Association. In 1997, for example, CHD claimed the lives of close to 470,000 Americans. CHD is caused by partial or complete clogging of the coronary arteries that nourish the heart. This blockage can choke the blood supply to areas of the heart, resulting in tissue death (also known as a heart attack).
"This process can narrow the artery by up to 90 percent," said Emeson, "leaving only a pinpoint. This occurs very gradually, over a long period of time. However, once you have a clot, and sudden occlusion, the muscle dies. People can have occlusion at 25 percent blockage."
Accumulating data support a link between moderate consumption of alcohol and a reduced incidence of and mortality due to CHD. Atherosclerosis, the accumulation of fatty streak lesions in the coronary arteries, is a precursor to CHD and is often associated with high serum cholesterol levels. In an earlier study, Emeson found that alcohol seemed to reduce the incidence of atherosclerosis. In this month's ACER study, Emeson found that - at least in experimental animals - moderate amounts of alcohol in the diet may not only reduce the size of atheroslerotic lesions in the aorta but may even halt the progress of these lesions after they have formed.
"Clearly I'm not advocating that everyone should be drinking alcohol," said Emeson, "but this helps explain the folklore that has been around for years that a shot or two of whiskey may be good for you. Most importantly, this kind of research helps us understand what the mechanisms are why does alcohol seem to help the heart? The idea is that if we can find the mechanism, we might be able to one day prevent the disease and bypass the alcohol."
"Evidence has accumulated over the last two decades," observed Sam Zakhari, director of the Division of Basic Research at the National Institute on Alcohol Abuse and Alcoholism, "suggesting that moderate drinking can reduce the risk of coronary artery disease, and researchers are beginning to understand the mechanisms of this effect. Thus, it is enticing to simply advise people to drink moderately. Yet moderate drinking is not risk-free, and the tradeoff between risk and benefits should be considered for each individual, taking into account age, gender, and lifestyle. Furthermore, some people should not drink at all."
Zakhari listed a number of factors that need to be considered when weighing the pros and cons of drinking alcohol. Since CHD is uncommon before age 35 in men and age 50 in women, he said, younger people derive no benefit from drinking and may instead increase their risk of having an accident or becoming involved in an altercation. Furthermore, he added, people taking medications - especially the elderly -risk complications from interaction with the alcohol. In addition, Zakhari cautioned that people who have a family history of alcoholism and/or certain medical conditions such as pregnancy should exercise extreme caution in their decision to drink.
Despite his words of warning about alcohol use, Zakhari acknowledged that "how moderate alcohol consumption protects against risk of coronary artery disease is a very important question." Thus far, he noted, promising molecular studies have focused on some of the factors involved in atherogenesis (the formation of lipid deposits in the arteries) and coronary artery stenosis (a narrowing of the coronary artery). "Extensive research is needed in the study of other factors involved in atherogenesis," he said, "including nitric oxide, hormones, platelet activation, eicosanoids, and cytokines, all of which alcohol use may effect."
This is, in fact, what Emeson hopes to do: further explore the mechanisms of alcohol's apparent reduction of CHD risk. "One of the things that alcohol may do is alter the balance of something called 'cytokines,'" he said. "Cytokines are hormone-like proteins, biological substances that almost all cells make, particularly blood cells. I think that alcohol may alter the balance of cytokines, which may tip the balance in favor of protection against atherosclerosis. We may one day find there is a way of accomplishing this without using alcohol."
Co-authors of the Alcoholism: Clinical & Experimental Research paper included: Vlasios Manaves, Brian S. Emeson, Lu Chen, and Igor Jovanovic of the Department of Pathology at the University of Illinois at Chicago College of Medicine. The study was funded in part by the National Institute on Alcohol Abuse and Alcoholism, and the National Heart Lung and Blood Institute.
Contact: Eugene E. Emeson, M.D.
University of Illinois at Chicago
Add'l Contact: Sam Zakhari, Ph.D.
National Institute on Alcohol Abuse and Alcoholism