Scientists now have a clear picture about the connection between binge drinking and heart attack.
Their study contributes to a growing body of evidence that drinking patterns matter as much, if not more, to risk for cardiovascular disease than the total amount consumed.
Going on a 'binge' means having five or more drinks for men, and four or more drinks for women, in two hours, according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA).
Many studies suggest that an irregular pattern of heavy drinking brings about a two-fold increase in risk for a fatal heart attack, even as moderate drinking has been shown to reduce risk (the red wine effect).
Alcoholic beverages contain ethanol, which is mostly converted into acetaldehyde once in the human system at 'binge' levels, with the levels of acetaldehyde remaining high for many hours after the binge has ended.
The new study clarified for the first time that binge levels of acetaldehyde cause an important type of immune cell, the monocyte, to become better able to stick to blood vessel walls, an important step in initiating atherosclerotic disease.
Researchers said that clarifying these mechanisms promises to empower the design of new treatments to counter the effects when combined with lifestyle change.
In the past, experts believed that atherosclerosis developed when too much cholesterol clogged arteries with fatty deposits called plaques. When blood vessels became completely blocked, heart attacks occurred.
Now most believe that the reaction of the body's immune system, more than the build-up itself, creates heart attack risk.
Vessel walls mistake fatty deposits for intruders, akin to bacteria, and call for help from the immune system.
Among other cell types, monocytes arrive with the goal of preventing infection, but end up causing inflammation that drives blood vessel blockage.
"Factors like binge-drinking have been linked to increased risk for heart disease, and the newer inflammatory model is beginning to explain how," said John Cullen, Ph.D., assistant professor in the Department of Surgery at the University of Rochester Medical Center.
"One of our experiments found that acetaldehyde, at levels found in the blood after binge drinking, increased the number of monocytes that can adhere to cells lining blood vessels by 700 percent," said Cullen, who led the study.
The authors hope the results of the new study empower public health campaigns that discourage binge drinking.
The study is published in the journal Atherosclerosis.