A large new study suggests that people who have up to seven drinks a week in middle age have a lower risk of heart failure over the long term than those who abstain – though too much wine, beer or liquor could lead to an earlier death from other causes.
The study authors cautioned that people with heart failure should avoid alcohol, and that their study does not mean that others should start drinking "with abandon".
The results are based on observation over time, so they cannot prove that moderate drinking protects against heart failure, they added.
Alcohol and better health
"We don't know if alcohol is protective or if people who drink a little bit might do other things that might be contributing to their better health," said Dr. Scott Solomon of Harvard Medical School in Boston, the study's senior author.
While previous research has shown a link between mild to moderate alcohol intake and lower risk of coronary heart disease, such as heart attacks, "what we didn't know was whether this would also extend to heart failure even in patients who did not have prior heart attacks," Solomon said.
Read: Regular drinking of small amounts lowers heart risk
"We were concerned because there is some evidence that alcohol is toxic to the heart directly," he said.
A moderate amount of alcohol is less than some people might expect – about seven drinks over the whole week. The study assumed that one drink contained 14 grams of alcohol, which is the amount in a little over five ounces of wine, 13 ounces of beer or 1.5 ounces of liquor.
What the data shows
The researchers used data from the large and ongoing Atherosclerosis Risk in Communities Study, following 14 629 adults who were 45 to 64 years old at the start of the study in 1987. People who didn't drink at all made up 61 percent of those included in the analysis, though 19 percent were former drinkers. About 25 percent of the study population drank up to seven drinks weekly, 8 percent averaged seven to 14 drinks a week, 3 percent had 14 to 21 drinks weekly and 3 percent drank 21 or more.
Men who had up to 14 drinks weekly were 20 percent less likely than abstainers to develop heart failure and women who drank up to 7 glasses weekly were 16 percent less likely, according to the results in the European Heart Journal.
"If we were giving a drug and doing this in a trial and showing that effect, people would say, okay that's a modest reduction," Solomon told Reuters Health. "It's simply not as robust for women," he said.
Read: Energy drinks, heart disease link
"It could be women are smaller in general and so this might have to do to some degree with body size. But also other factors with gender in terms of how we metabolize alcohol," he added.
A higher percentage of men and women developed heart failure if they were former drinkers compared to those who never drank. Men and women who drank 21 or more drinks weekly were also more likely to die from other causes than those who didn't drink that much.
Not a random move
"The decision to stop drinking may not be random, it may be influenced by other factors that might be related to risk of illness," said Solomon, who also directs Noninvasive Cardiology and the Cardiac Imaging Core Laboratory and Clinical Trials Endpoints Centre at Brigham and Women's Hospital in Boston.
Showing that link between a low to moderate amount of alcohol and lower risk of heart failure (and not just heart attacks or stroke) is a "novel" finding, said Dr. Andrew J. Sauer at the Centre for Heart Failure, Heart Transplantation, Mechanical Assistance at Northwestern University Feinberg School of Medicine in Chicago.
Read: Light drinking lowers stroke risk in women
"A lot of us in the heart failure community have been suggesting something similar for patients," said Sauer, who was not involved in the study.
He pointed out that the researchers accounted for factors like age, education, body mass index, smoking, cholesterol and high blood pressure, which bolsters the suggestion that alcohol is what protected people from heart failure.
A little more alcohol . . .
But, the study did not show how often people were drinking daily or whether they might have even had seven drinks in one night, he said. Sauer also noted that many people pour seven or eight ounces of wine when they drink, and people who could stick to a truly moderate amount "are probably very disciplined" and might therefore have healthier lifestyles.
"A little more alcohol in your diet is continuing to show up . . . as a potential protector for cardiovascular events," Sauer said. "But until there is a trial where people are randomised to abstaining or drinking low to moderate amounts, we'll never know for sure."
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