Alcohol and the Heart

What Should Doctors Tell Their Patients?

Couple toasting wine at outdoor restaurant, focus on glasses
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Is alcohol good for the heart? Or, is alcohol bad for the heart? Surprisingly, it looks a lot like the answer to both of these questions may be - Yes.  Like many things in life, a little of it may be beneficial; but too much of it can be ruinous. 

Doctors, alcohol, and the heart

Doctors have struggled for several years now over whether to tell their patients about the potential cardiac benefits of alcohol.

Over 60 clinical studies have suggested that light to moderate alcohol consumption (the equivalent of one or two 1 ½ oz. drinks of alcohol per day) can increase HDL cholesterol levels (the “good” cholesterol,) can reduce the incidence of myocardial infarction (heart attack), and may have other cardiovascular benefits.

However, excessive alcohol consumption reliably causes a number of severe and often fatal medical problems, not to mention the destructive social pathologies associated with alcoholism itself.

For all these reasons, a special advisory panel of the American Heart Association issued a formal statement urging doctors not to recommend alcohol to their non-drinking patients as a means of reducing the risk of heart disease. This makes perfect sense. If doctors were seen to be encouraging alcohol, that would not only be politically incorrect, but might also lead to a significant increase in alcohol-related medical and social problems.

Still, the apparent cardiac benefits of alcohol creates something of a dilemma for doctors.

The Evidence in Favor of Alcohol

Numerous prospective studies now suggest that people who engage in light to moderate alcohol consumption have a substantially reduced risk of coronary artery disease (CAD) - by as much as 40 - 70% - compared to those who drink either no alcohol, or those who drink more heavily.

 And in a large meta-analysis that included over 80 observational studies, those with light to moderate alcohol intake had a 25% reduction in death from cardiovascular causes.

People who engage in light alcohol consumption appear to have a significantly reduced risk of developing heart failure.

Light to moderate alcohol consumption may help to prevent type II diabetes and metabolic syndrome. And in people who have diabetes, it may help to protect against CAD.

Up to two drinks per day may help to protect against stroke.

How Can Alcohol Protect the Heart?

Theories as to how light to moderate alcohol consumption can benefit cardiovascular health include the following:

  • Alcohol increases HDL cholesterol levels
  • Alcohol has antioxidant activity
  • Alcohol increases insulin sensitivity
  • Alcohol may help prevent abnormal blood clotting
  • Alcohol in low doses has anti-inflammatory properties

While it is widely believed that red wine may have special protective properties (largely stemming from the antioxidant properties of red grapes), in fact the overall data strongly suggests that it is the alcohol itself that is cardioprotective in small doses - regardless of the particular type of alcoholic beverage consumed.

The Evidence Against Alcohol

It is noteworthy that in all the studies assessing the effect of alcohol on the heart, women who consumed more than two drinks a day, and men who consumed more than three, had a substantial increase in overall cardiovascular mortality, including sudden death. Furthermore, several studies show that binge drinking (abstaining for several days, but drinking heavily on the days when alcohol is consumed) is associated with a substantially increased risk of CAD and of cardiovascular death.

In addition, drinking large amounts of alcohol is a well-recognized cause of cardiomyopathy and heart failure. People who have more than two drinks per day have a significantly increased risk of developing hypertension.  And consuming more than two drinks per day appears to significantly increase the risk of stroke.

Both heavy drinking and binge drinking increase the risk of atrial fibrillation.

The Bottom Line

It appears quite evident that the relationship between alcohol and cardiac risk follows a "J-shaped" curve.  Cardiac risk is lower when low to moderate alcohol is consumed than if either no alcohol is consumed, or if higher amounts of alcohol are consumed.

The problem for professional bodies and guideline-writers, obviously, is that many, many people find it difficult or impossible to limit their alcohol to one or two drinks per day.  If guidelines actively promoted light alcohol consumption for the population, there is every reason to believe that the overall result would be a negative one, rather than a positive one.  So, despite all the evidence regarding the cardiovascular benefits of light alcohol consumption, you should not hold your breath waiting for guidelines (or your doctor) to recommend such a thing.

Sources:

Di Castelnuovo A, Costanzo S, Bagnardi V, et al. Alcohol dosing and total mortality in men and women: an updated meta-analysis of 34 prospective studies. Arch Intern Med 2006; 166:2437.

Kloner RA, Rezkalla SH. To drink or not to drink? That is the question. Circulation 2007; 116:1306.

Ronksley PE, Brien SE, Turner BJ, et al. Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. BMJ 2011; 342:d671.

Costanzo S, Di Castelnuovo A, Donati MB, et al. Alcohol consumption and mortality in patients with cardiovascular disease: a meta-analysis. J Am Coll Cardiol 2010; 55:1339.

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