Contrary to what you may have heard previously, it now appears that any amount of alcohol can be harmful. Researchers reviewed more than 50 studies involving more than 260,000 people and concluded that reducing alcohol consumption helps to prevent heart attacks, whether a person is a light, moderate or heavy drinker (British Medical Journal, July 11, 2014).
Alcohol can damage every type of cell in your body, and your liver is the only organ that protects you. Your liver breaks down alcohol at a relatively constant rate, but first alcohol is converted to acetaldehyde, which is even more poisonous. It can make you feel like throwing up and make your face burn. Some people have a genetic variant of the “alcohol dehydrogenase 1B” gene, which breaks down alcohol much faster to the more potent acetaldehyde dehydrogenase. Since drinking even small amounts of alcohol makes these people very sick, they usually restrict or avoid alcohol completely. The researchers found that people with this gene, who are forced to restrict alcohol because it makes them sick, are at a 10 percent reduced risk for heart attacks. There may be other reasons to explain the reduced risk, beyond their avoidance of alcohol.
A study of 79,000 Swedish adults, aged 45 to 83, followed for up to 12 years, shows that those who drink any amount of wine or liquor daily are at increased risk for atrial fibrillation, an abnormally fast heartbeat that can cause clots, strokes and heart failure (Journal of the American College of Cardiology, July 14, 2014). The more they drank, the more likely they were to develop this irregular heartbeat.
Binge drinking, defined as having five or more drinks in a single bout, increased risk even more. Data from six prior studies including more than 12,500 cases of atrial fibrillation showed that each additional drink per day of any type of alcohol boosted risk of irregular heartbeat by eight percent. Many other studies have associated drinking alcohol with atrial fibrillation, high blood pressure, diabetes, heart failure and strokes. Association is not cause, but I believe that these studies give reason for caution.