ORLANDO, Fla. - Like chocolate and wine, the darker the beer, the better it could be for your heart, according to a new study.
In a comparison of Guinness Stout, a dark beer, and Heineken, a light beer, the darker brew had substantially more anti-clotting activity, according to a University of Wisconsin-Madison scientist who presented his findings yesterday at the annual meeting of the American Heart Association.
Guinness was about twice as effective at preventing the blood platelets from clumping and forming the kind of clot that can cause a heart attack, according to the study's main author, John Folts, a professor of medicine and nutritional director of the University of Wisconsin Coronary Thrombosis Research and Vascular Biology Laboratory.
The beneficial effect comes from flavonoids, anti-oxidant compounds that provide the dark color in many fruits and vegetables. There are hundreds of flavonoids in beer, Folts said.
Flavonoids also work to prevent the oxidation of cholesterol, which plays a role in causing atherosclerosis - known as hardening of the arteries. They also help arteries to dilate, which improves blood flow and blood pressure, he said.
Folts did his research in test tube studies and on eight dogs.
He said a person would have to reach a blood alcohol level of 0.06 in order to get the optimal anti-clotting effect. He said that for the typical person, that could be accomplished with two 12-ounce bottles.
Doctors warned that even though dark beer might have heart-healthy properties, it has a downside that could negate any benefit: extra calories.
Dark chocolate and red wine have similar properties but also provide extra calories. Obesity raises the risk of heart disease.
Ronald Korthuis, a professor of physiology at the Louisiana State University Health Sciences Center, said Folts' research bolsters epidemiological studies suggesting that alcoholic beverages can reduce heart attacks.
"What is impressive about Dr. Folts' observations is that the flavonoids in dark beer produce anti-platelet effects that rival those of aspirin," Korthuis said.
Folts said his goal is to isolate the beneficial compounds and put them into a pill.