Alcohol and the Heart

Can a drink a day keep the cardiologist away? Does alcohol decrease the risk for heart attack and cardiac death or is it harmful to the heart?

Before tackling this question, some definitions are in order. Moderate drinking is defined as two or less drinks per day for men and one or less for women.  A drink is 12 ounces of regular beer or 5 ounces of wine or 1.5 ounces of spirits.

In large studies looking at alcohol and cardiac mortality there appears to be a J shaped curve. Patients with moderate alcohol consumption were at the bottom of the curve (the lowest mortality) with 16% reduction in deaths for men and 12% reduction for women compared to nondrinkers. Nondrinkers had an intermediate mortality rate. Patients with heavy alcohol use, greater than 4 drinks per day, had the highest mortality. The possible heart protective effect of alcohol was even given a name, “the French Paradox”, based on the observation that people in France have low levels of heart disease despite diets high in saturated fat.  In 1991, 60 Minutes aired a show on the paradox, and it was suggested that the high French intake of alcohol, particularly red wine, was responsible for the effect and the lower cardiac mortality. After the show, red wine consumption in the US increased by 44%.

How does alcohol decrease cardiac disease?  While the answer to this question is still not known, it had been theorized that resveratrol, an antioxidant found in the skin of grapes, was the mechanism. Resveratrol, which is found in red wine, is purported to have anti-inflammatory properties and to increase longevity. However, it has been found that the amount of resveratrol in wine is rather low and cannot explain any protective benefits.  Alcohol itself, it seems, may provide benefit by increasing HDL (“good cholesterol”) and decreasing inflammation.  Alcohol, especially after meals, increases insulin sensitivity and sugar metabolism, keeping weight down and diabetes risk low.  On the other hand, heavy alcohol consumption can cause liver disease and cancer as well as having adverse effects on the heart, such as hypertension (elevated blood pressure), atrial fibrillation (an irregular rhythm from the upper chambers of the heart), congestive heart failure and stroke.

Alcohol is a well-known heart toxin. In patients who drink and are susceptible, alcohol can weaken the heart muscle (a condition called cardiomyopathy), decreasing the heart’s pumping ability and causing congestive heart failure, with fluid filling up in the lungs and leading to shortness of breath.  If the heart’s ability to pump blood continues to worsen, the body is deprived of oxygen, several organ systems fail (for example the kidneys stop working) and death follows. In extreme cases, alcoholic cardiomyopathy can lead to heart transplantation. Fortunately abstaining from alcohol once the diagnosis is made can lead to recovery of the function of the heart muscle.  The amount of alcohol needed to cause cardiomyopathy is not known. Women need lower amounts than men and the same consumption in one person may cause no adverse effect while in another person it may cause heart failure. Alcohol is implicated in atrial fibrillation as well. Atrial fibrillation is dangerous in that it can lead to heart failure or blood clots and stroke. Drinking less than 2 drinks per day was not associated with an increased risk for atrial fibrillation. However, for those who drink more than two per day, the risk of atrial fibrillation increases 8% for each drink above two. The more alcohol consumed, the greater the risk for atrial fibrillation. In addition, binge drinking can lead to atrial fibrillation, a phenomenon termed “Holiday Heart Syndrome”  (due to excess consumption of alcohol on weekends or on holidays).  Lastly, for some people, even moderate alcohol consumption can be dangerous, including patients on blood thinners or those with uncontrolled high blood pressure.

Clearly, alcohol is a double-edged sword and the scientific community is still split over whether it is beneficial or not.  There are several factors to keep in mind regarding the data on alcohol’s cardiac protective effects. In almost all of the studies, patients are asked about their alcohol consumption rather than having it measured. This certainly can lead to inaccurate data, as many people will not be truthful about their alcohol use.  It is not known whether moderate drinking is truly protective or whether it is a marker of a healthy lifestyle (moderate drinkers tend to have better over all health, watch a better diet and exercise more than heavy drinkers).  It had been thought that wine was better than other types drinks, however, it seems that the type of alcoholic beverage is less important than the amount and pattern of usage.  In addition, more recent data has shown that the death rates between moderate drinkers and nondrinkers are not that different. In fact, it has been suggested that no amount of alcohol is safe for the heart.

What then is the recommendation for alcohol use? No health agency or major medical group recommends drinking for health purposes. The American Heart Association suggests that if you don’t drink, then don’t start. If you choose to drink alcohol, do so in moderation, without binge drinking. Further, if your moderate drinking is wine with meals, then the benefit seems to be the greatest.