Two alcoholic beverages a day may improve heart health, according to a new study from the University of Rochester Medical Center. Binge drinking, however, appears to have the opposite effect.

Led by John Cullen, a research associate professor, the study found that moderate drinking – two drinks a day – decreased atherosclerosis, or the hardening and narrowing of arteries. Atherosclerosis can lead to heart attack or stroke.

Binge drinking – seven drinks a day across a two day period – increased the development of atherosclerosis, indicating that drinking in moderation is really the best course of action.

“People need to consider not only how much alcohol they drink, but the way in which they are drinking it,” said Cullen.

“Research shows that people have yet to be convinced of the dangers of binge drinking to their health; we’re hoping our work changes that.”

Using mice, Cullen and his research team used three groups to observe the impacts of alcohol consumption and cholesterol. The first group received the ethanol equivalent of two drinks every day while a second group received seven drinks across a two day period.

A third group received a cornstarch mixture to serve as a comparison to the other two.

Mice in all three groups were fed a diet high in fat and cholesterol to encourage the development of atherosclerosis.

The levels of bad cholesterol dropped 40 percent in the two drinks a day group while it rose by 20 percent in the binge drinking group when both were compared to the cornstarch mixture group.

Both ethanol groups saw a small jump in good cholesterol levels, but Cullen considered this a short-term effect.

The plaque that builds up in arteries as a result of fatty diets also decreased in the moderate drinking group while it went up for the binge drinking group.

“This evidence is very interesting because it supports a pattern of drinking that is emerging in clinical studies as both safe and seemingly most protective against heart disease – frequent consumption of limited amounts of alcohol,” said Dr. Kenneth Mukamal, an associate professor of medicine at Harvard Medical School who was not involved in the study.

Cullen intends to build on these findings by studying genes that may turn on or off as a result of alcohol consumption to determine if they are the influencing factors.

The study was published in the journal Atherosclerosis.

The study was funded in part by the Founders Affiliate of the American Heart Association and the National Institute on Alcohol Abuse and Alcoholism at the National Institutes of Health.