For decades, many scientific studies have suggested that moderate drinking was good for most people’s health and could even help them live longer. However, a new analysis of more than 40 years of research has found that many of those studies were flawed, and the opposite is true.
The review published in The New York Times, which analyzed over 100 studies of almost five million adults, found that the risks of premature death increase significantly for women who consume more than 25 grams of alcohol per day, which is less than two standard cocktails. For men, the risks increase significantly at 45 grams of alcohol per day, which is just over three drinks.
The new report was not designed to develop drinking recommendations but to correct methodological problems that plagued many of the older observational studies. The earlier reports consistently found that moderate drinkers were less likely to die of all causes, including those not related to alcohol consumption. However, most of these studies were observational, meaning they could identify links or associations but could be misleading and did not prove cause and effect.
The new study’s authors said that the older studies failed to recognize that light and moderate drinkers had various other healthy habits and advantages. The abstainers used as a comparison group often included former drinkers who had given up alcohol after developing health problems, making the current drinkers look healthier and have lower mortality.
“When you compare this unhealthy group to those who go on drinking, it makes the current drinkers look more healthy and like they have lower mortality,” said Tim Stockwell, a scientist with the Canadian Institute for Substance Use Research and one of the authors of the new report. Dr. Stockwell and his colleagues corrected these errors and others and found that the supposed health benefits of moderate drinking shrink dramatically and become non-statistically significant.
The comparisons of moderate drinkers with non-drinkers were flawed for numerous reasons. People who abstain completely from alcohol are a minority, and those who aren’t teetotalers for religious reasons are more likely to have chronic health problems, to have a disability, or to be from lower income backgrounds.
Moderate drinkers tend to be moderate in all ways. They tend to be wealthier, more likely to exercise and eat a healthy diet, and less likely to be overweight. They even have better teeth, scientists say. “They have a lot of things going for them that protect their health, that have nothing to do with their alcohol use,” Dr. Stockwell said.
The idea that moderate drinking may be beneficial dates back to 1924 when a Johns Hopkins biologist named Raymond Pearl published a graph with a J-shaped curve. The low point in the middle represented the moderate drinkers who had the lowest rates of mortality from all causes. The high point in the J represented the well-known risks of heavy alcohol consumption, such as liver disease and car crashes, and the hook on the left represented abstainers.
In more recent decades, wine and particularly red wine, developed a reputation for having health benefits after news stories highlighted its high concentration of a protective antioxidant called resveratrol, which is also found in blueberries and cranberries.
However, the moderate alcohol hypothesis has come under increasing criticism over the years as the alcohol industry’s role in funding research has come to light. Newer studies have found that even moderate consumption of alcohol, including red wine, may contribute to cancers of the breast, esophagus, and head and neck, high blood pressure, and a serious heart arrhythmia called atrial fibrillation.
