'Moderate alcohol intake convincingly confers a heart health benefit,' one expert maintains. 'At this point, the burden of proof is on those wishing to refute this.'

Studies published in the 1970s and 1980s have suggested that small to moderate amounts of alcohol can protect against heart disease, and that this benefit outweighs any adverse health effects of light drinking.

But this research is flawed, according to Dr. Rod Jackson, a professor of epidemiology at the University of Auckland, in New Zealand. "All the current research on alcohol and heart disease is from nonrandomized studies, which means it is prone to bias," he said.

Jackson and his colleagues make their case in an article in the Dec. 3 issue of The Lancet.

'Don't Kid Yourself'

Jackson said that nondrinkers are different from light-to-moderate drinkers, who are also different from heavy drinkers. "So, it is likely that the apparent benefits of light-to-moderate drinking on the heart are overestimated because light-to-moderate drinkers are light-to-moderate in their other behaviors as well, which is giving them some of the observed benefits, rather than the alcohol," he said.

In addition, heavier drinking is associated with increased heart disease, "but the adverse effect may be in part to do with heavier drinkers having other 'heavy' behaviors that give them more heart disease," Jackson said. "We probably overestimate the benefits of light-to-moderate drinking on the heart and overestimate the harms of heavier drinking on the heart."

While drinking may not protect your heart, it may not be a danger, Jackson added. "There are probably no levels of drinking that give you any health benefits, but up to one to two drinks per day is not harmful, just neutral," he said.

"Don't drink to protect yourself from heart disease risk," Jackson said. "Drink modestly, up to one to two drinks per day maximum, if you enjoy alcohol, but don't kid yourself that it is protecting your heart."

Probably Not Harmful

One expert agreed there is no proof that alcohol protects you from heart disease, and that moderate drinking is probably not harmful.

"At a practical level, I do not think the evidence is strong enough to support the recommendation of alcohol consumption to reduce heart disease to someone who does not normally drink," said Dr. J.C. Garbutt, a professor of psychiatry at the University of North Carolina.

"We know there are clear reasons why individuals shouldn't drink -- including risk of alcoholism and medical risks such as breast cancer and liver disease," Garbutt said. "However, if an individual is a moderate drinker and does not have risk factors that would make alcohol consumption problematic, then moderate drinking is probably reasonable from a health perspective."

Likely to Have a Protective Effect

Another expert thinks alcohol is likely to have a protective effect.

"I think Jackson and colleagues are likely to be wrong," said Dr. David L. Katz, an associate professor of public health and director of the Prevention Research Center at Yale University School of Medicine.

"While we don't have randomized trials of alcohol intake and heart attacks, we do have studies of the effects of alcohol, and especially red wine, on blood lipids, blood pressure, platelet stickiness, and even the ability of blood vessels to dilate," Katz said. "In all instances, moderate alcohol intake produces clear and quantifiable benefits."

Alcohol epitomizes the double-edged sword, Katz said. "The evidence is strong that it does, indeed, confer cardiovascular benefit at moderate dosing. But the harms quickly start to outweigh any benefits as the dose rises. So, the public health message about alcohol must be a cautious and judicious one."

"Moderate alcohol intake convincingly confers a heart health benefit," Katz said. "At this point, the burden of proof is on those wishing to refute this."

More information: For more on alcohol and the heart, head to the American Heart Association.