A glass of wine a day helps keep heart disease away, right? We've all heard that enticing claim. But is it true?

Although an excessive amount of red wine remains a definite risk for health, it has been suggested that mild-to-moderate amounts of red wine may provide a net beneficial effect. The "French paradox" describes the epidemiological observation that French people have a relatively low incidence of coronary heart disease (CHD) despite having a diet relatively rich in saturated fats.

According to some studies, drinking modest amounts of alcohol (one to two drinks per day) may be associated with reduced mortality related to heart disease. These studies suggest that the components in red wine such as flavonoids in the grape skin and other antioxidants protect the heart and vessels from the damaging effects of free oxygen radicals produced by our bodies.

That said, specific links between red wine and fewer heart attacks have not been completely understood.

However, recent research by Tim Stockwell, Ph.D., director of the Centre for Addictions Research at the University of Victoria, in British Columbia, Canada, indicates a possible flaw in the assumption that those who drink moderately may have a lower risk for heart disease than those who do not drink at all.

His analysis of 45 previous cohort studies reveals that nondrinkers may have stopped alcohol consumption or cut down for health reasons or increasing age reasons. Furthermore, older persons who continue to be moderate drinkers are usually healthier and not taking medications that may interact with alcohol.

Basically, Stockwell reports that people change their drinking habits over time.

The 45 unique studies selected included 269 estimates of the risk relationship between level of alcohol consumption and CHD mortality, more than in previously published meta-analyses. There were 2,913,140 subjects and 65,476 deaths available for the analysis.

In addition to newly published studies, Stockwell and colleagues included several older studies omitted from previous meta-analyses. An additional nine published studies that met the selection criteria for the study have been included since the last meta-analysis was published.

Drinking categories were defined and reclassified as:

  • former drinkers now completely abstaining
  • current occasional drinkers, defined as up to one drink per week (<1.30 g per day)
  • current low-volume drinkers, up to two drinks or 1.30 to 24.99 g per day
  • current medium-volume drinkers, up to four drinks or 25 to 44.99 g per day
  • current high-volume drinkers, up to six drinks or 45 to 64.99 g per day
  • current higher-volume drinkers, six drinks or 65 g or more per day

These results, however, were not the same in younger drinkers, those 55 years and under. Studies that looked at younger drinkers (ages 55 and younger) until they were older and more prone to heart disease showed no benefits from moderate drinking.

Stockwell remains skeptical about the claim that moderate drinking is cardio-protective. He suggests that people should not drink just because they think it wards off disease and recommends future prospective studies to avoid biased abstainer reference groups as well as to minimize other forms of selection bias, including those from competing disease risks.