Drinking moderate amounts of alcohol helps protect men and women from developing heart disease compared with teetotalers, two new Canadian papers conclude.

The first is a review of 84 studies on alcohol consumption and heart disease. It concluded that people who drink one drink or less per day had a 1.4 to 2.5 times reduction in risk of developing cardiovascular disease and dying of heart disease and stroke compared with those drinking no alcohol at all.

Extensive research has established the link between drinking alcohol and decreased cardiovascular risk, Professor William Ghali of the University of Calgary and his co-authors concluded in the British Medical Journal.

But there's a lingering question of whether there is a cause-and-effect relationship.

To try to answer it, a second paper published in the same issue looked at biomarkers such as levels of high density lipoprotein also called HDL or "good" cholesterol in drinkers and non-drinkers.

It was a review of 63 studies. Moderate alcohol consumption had favourable effects on such physical markers of heart disease like HDL, levels of inflammation, and the condition of blood vessels, Dr. Susan Brien of the University of Calgary and her co-authors concluded. 

Moderate consumption was defined as up to one drink or 15 grams of alcohol per day for women and up to two drinks or 30 grams of alcohol per day for men. It was the alcohol content rather than the type of drink (wine, beer or spirits) that offered health benefits.

"With respect to public health messages, there may now be an impetus to better communicate to the public that alcohol, in moderation, may have overall health benefits that outweigh the risks in selected subsets of patients," Ghali's team concluded.

The researchers recognized the tricky balance between identifying heart benefits of drinking alcohol and its harmful effects on some in society.

"The debate on how to integrate this evidence into clinical practice and public health messages will require integration of all possible effects of alcohol — from injury and violence to glucose metabolism and inflammation — and recognition that these effects may be distributed unequally across the population. For example, injury risk probably disproportionately affects younger individuals, whereas cardiovascular disease mainly affects older adults."

The research was funded in part by the Robert Wood Johnson Foundation.