Studies show moderate drinking confers heart benefits

Q: I've heard that drinking red wine, or any alcoholic beverage, in moderation is “heart-healthy.” Is it true, and is red wine any healthier than other alcoholic beverages?

A: There are many studies of the two questions you ask. As for the first question, most studies have found that moderate drinkers are less likely to develop Type 2 diabetes and heart disease. That's when moderate drinkers are compared either to non-drinkers or to heavy drinkers.

“Moderate drinkers” refers to men who have an average of one to two alcoholic drinks per day, and women who have an average of one drink per day. The difference between men and women is because women metabolize alcohol somewhat differently from men.

A study published in 2015 from Harvard Medical School and other institutions analyzed results from nearly 15,000 people. The study lasted nearly 25 years.

No one had heart failure at the beginning of the study. By the end of the study, however, some did. But moderate drinkers were 20 percent less likely than non-drinkers or heavier drinkers to develop heart failure.

This positive effect of moderate drinking was somewhat stronger in men than in women. The study looked primarily at heart failure, and not at other types of heart problems.

Now to your second question, about whether red wine is a more heart-healthy type of alcoholic drink than other alcoholic beverages.

Here, I'd say the evidence is less clear.

A study reported in late 2015 got a lot of attention in the media for showing that red wine is heart-healthy. In fact, that study did not really compare red wine to all other types of alcoholic beverages.

The study involved over 200 adults who were at high risk for heart disease because they had Type 2 diabetes. Participants were assigned at random to drink 5 ounces (two-thirds of a cup) of either red wine, white wine or mineral water each day. The drinks were provided for free, to encourage study participants to drink as they were assigned by the study to do.

After about two years, the red wine drinkers had higher HDL cholesterol (“good” cholesterol), lower ratios of total cholesterol to HDL cholesterol, and fewer markers of “metabolic syndrome” (a cluster of conditions that increase the risk of heart disease, stroke and diabetes), compared to the mineral water drinkers.

Each of these changes has been linked to lower rates of heart disease. However, the study was too short to determine if heart disease rates were actually lowered.

Interestingly, the white wine drinkers had somewhat different beneficial effects.

Compared to the mineral water drinkers, the white wine drinkers had lower blood sugar levels, lower levels of triglyceride fats and less insulin resistance.

Each of these changes, too, has been linked to lower rates of heart disease. But again, the study was too short to determine if heart disease rates were actually lowered.

To make a long story short, moderate drinkers have heart benefits, compared to non-drinkers or heavier drinkers.

Heavier drinking puts the heart (and other organs) at risk.

It's not clear that red wine is superior to other alcoholic beverages.

• Dr. Komaroff is a physician and professor at Harvard Medical School. For questions, go to AskDoctorK.com.