In a report published in the February 10 issue of Circulation, healthy seniors who drink moderate amounts of alcohol (one to seven drinks per week) were shown to have have lower blood levels of CRP and interleukin-6 (IL-6, another marker of inflammation) than their non-drinking counterparts, or those having more than seven drinks a week. (CRP and other markers of inflammation have been associated with an increased risk of cardiovascular disease. Click here for a brief review of CRP and CRP testing).
The data was accumulated from the 2574 healthy American seniors participating in the Health, Aging, and Body Composition Study. Those participants who had 1 - 7 drinks per week had lower CRP and IL-6 levels than other participants. Notably, however, those who consumed more than 7 drinks per week had the highest CRP and IL-6 levels of all. The data in this study was adjusted to account for other factors that might influence inflammatory markers, such as age, race, gender, smoking, physical activity, or diabetes.
The authors postulate that alcohol has a direct effect on IL-6 metabolism. IL-6, in turn, is one of the factors that regulates CRP levels - by altering IL-6, then, alcohol can affect both kinds of inflammatory markers. However, since excessive alcohol consumption often causes alcohol-related inflammatory diseases (such as hepatitis), drinking more than 7 drinks per week can increase inflammatory markers, thus negating any possible beneficial effects of more moderate alcohol consumption.
This study does not help doctors decide whether they ought to tell their patients about the cardioprotective effects of alcohol. While it offers one mechanism to explain how alcohol might protect the heart, this study at the same time re-emphasizes the risks of alcohol. Moderate amounts of alcohol might indeed be beneficial to many, but drinking more than moderate amounts is clearly dangerous. Doctors know that many individuals have a hard time controlling the amount of alcohol they consume, and by encouraging "some" drinking in their patients, doctors may very well do more harm than good. This is why the formal policy of the AHA is to discourage doctors from telling their patients that alcohol might be beneficial.