Dark Chocolate Helps Keep Blood-Clotting Dangers at Bay

The "chocolate offenders" admitted to eating chocolate on the sly, however. Rather than just disqualifying them, the study authors decided to use their cheating ways for an additional analysis. Becker and her team tested platelet samples from the "offenders" and from a control group to see how long it took for platelets to clump together.

Chocolate appeared to slow clotting. On average, platelets in the chocoholics took 130 seconds to stick together, and in the control group about 123 seconds.

A test of urine for the waste products of platelet activity found that chocolate eaters also had less activity and produced fewer waste products.

"People who ate chocolate had markedly lower amounts of urinary excretion of this byproduct of platelet activity, which meant that the platelets are not being activated and not clumping so much in the body," Becker said. "The magnitude of the difference is very significant."

"What you eat in everyday life in relatively small quantities, as long ago as 12 hours, affects platelet function -- which is kind of a way to express the amount of time it takes for blood to clot," she continued. "It makes blood less sticky and less likely to clot and less likely to be part of a process that could cause a heart attack."

The bottom line? A little high-quality chocolate once in a while probably won't kill you. But follow nutritionists' advice, too -- don't ingest pounds of the stuff because the sugar and fatmaykill you.

More information

There's more on diet and the heart at the American Heart Association.

SOURCES: Diane Becker, Sc.D., professor, medicine, Johns Hopkins University School of Medicine, Baltimore; Robert H. Eckel, M.D., professor, medicine, University of Colorado School of Medicine, Denver, past president, American Heart Association; Nov. 14, 2006, presentation, American Heart Association Scientific Sessions, Chicago