Cheers! Moderate Drinking May Help Prevent Blood Clots

From the WebMD Archives

April 26, 2000 -- As with food and exercise, moderation is key to reaping the benefits of drinking alcohol. And, yes, there are benefits. Studies have shown men and women, middle-aged or older who have one or two drinks per day have lower death rates from heart disease than both teetotalers and those who drink three drinks or more a day. Part of the reason is that alcohol seems to increase the concentration of heart-healthy HDL (or "good") cholesterol. Another benefit, according to a new study, is that a moderate amount of alcohol acts as a kind of blood thinner.

Researchers at Georgetown University Medical Center in Washington, D.C., discovered that the alcohol equivalent of two drinks decreases the clumping together of platelets, cells that are essential to blood clotting. This is important because the formation of a blood clot that blocks an artery leading to the heart is the triggering event in a heart attack.

This new research may also partially explain the so-called French paradox, which is the fact the French have less heart disease than Americans, despite the fact that they eat high-fat foods. Ingredients in red wine, which the French also enjoy as part of their culture, are thought to be partially responsible.

"Whether it's red wine or alcohol has not really been addressed," Adam K. Myers, PhD, tells WebMD. He adds that it may be an effect of alcohol mixed with the substances found in grapes.

Myers and his colleagues also found that these effects of alcohol on blood clotting were greater in women than men. "The differences between men and women really is a surprise, and it's going to be an important issue to think about in the future," Myers explains, adding that scientists need to be aware that there may be gender and racial differences in people's responses to alcohol.

The participants in the study were given enough grain alcohol mixed in a soft drink to equal either one or two drinks of alcohol. Their blood was then drawn one hour after the drink to test the alcohol level in the body and to see what effects there were on blood clotting. One drink did not have a significant effect, but the higher dose prevented the platelets from sticking together and clotting. Whether the effect would last is unknown. Myers says they were only looking at a single dose of alcohol, and any effects after this point will need further study. He is professor and director of graduate studies in the department of physiology and biophysics at Georgetown University Medical Center.

Myers is not suggesting that people who don't drink should start, but, he says, from the point of view of protecting against heart disease, "I would suggest that moderate drinking ? and no binge drinking ? is probably not harmful. I would not leap to conclusions about any particular beneficial effect of drinking in general or drinking any specific type of beverage."

"The small magnitude of the changes ? is only a clue to what alcohol does to blood clotting," Thomas DeLoughery, MD, who was not involved in the study, tells WebMD. He also points out that methods of studying platelets in blood that have been removed from the body are not as precise as methods used to evaluate them while they are circulating in the bloodstream. Myers' tests on the platelets were done in a test tube.

DeLoughery acknowledges that studies on large groups of people have shown that those who consume moderate amounts of alcohol have fewer heart attacks, and he finds the Georgetown University study interesting. Nevertheless, he says bigger and better studies in humans are needed to determine the true effect of moderate alcohol use on blood clotting. "Certainly one should not adopt a potentially risky habit based on one laboratory study," he adds. DeLoughery is associate professor of medicine and director of anticoagulation services at Oregon Health Sciences University in Portland.

Vital Information:

  • Studies have shown that people who drink moderate amounts of alcohol have lower death rates than those who abstain from drinking or who drink heavily.
  • Alcohol is known to increase levels of the "good" cholesterol, or HDL, and new research shows that it may act as a blood thinner.
  • In the new study, drinking alcohol decreased the clumping together of clotting cells in the blood, a process that can lead to blood vessel blockages in the heart and possibly a heart attack.