A study has shown that elderly people who drank two or more alcoholic drinks per day had hearts with thicker walls and larger pumping chambers, and possibly reduced heart function, researchers say.
Alcohol may protect against problems like heart attacks, said senior author Dr. Scott D. Solomon, "but in high quantities alcohol is a heart toxin."
"We wanted to determine whether there were any subtle effects on heart structure," said Solomon, of Brigham and Women's Hospital in Boston, U.S.
How the study was done
As reported in Circulation: Cardiovascular Imaging, the researchers analysed data on more than 4,000 men and women from an ongoing study. Participants had their heart imaged between 2011 and 2013 at an average age of 75.
"We got a very good look at the size of the heart chambers and how well is it contracting and relaxing," Solomon told Reuters Health.
About 2,400 participants said they did not drink. About 1,500 said they consumed one to seven drinks per week, 402 said they had seven to 14 drinks and 195 said they had more than 14 drinks per week.
As the number of drinks per week increased, so did the diameter of the hearts' two left chambers: the atrium, which takes oxygen-rich blood from the lungs, and the ventricle, which delivers the oxygenated blood to the rest of the body.
For men, as drinks per week increased, so did the mass of the left ventricle.
For women, more alcohol intake was tied to a reduced amount of blood the left ventricle was able to pump out with each contraction.
"We found that as you get past the moderate alcohol exposure into two drinks or above per day in men, we start to see evidence of alteration of structure and function that we think could potentially in the long term be deleterious," Solomon said.
The threshold for women was lower at about roughly one drink per day, he said.
"I never recommend that people start drinking if they haven't," said Dr. Mary A. Whooley of the department of Veterans Affairs Medical Center in San Francisco.
"The potential benefits of alcohol do not outweigh the risk," said Whooley, who was not part of the new study.
High amounts of alcohol may have a similar toxic effect on the cells of the heart muscle for younger people as well, but the changes may be harder to see, she told Reuters Health.
Changes in heart structure may reverse themselves when drinking stops, but this study was not designed to answer that question, Solomon said.
Heavy drinking also increases the risk of liver damage and driving accidents, he said.
"It's definitely not all about the heart when you talk about alcohol," he said.
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Sources: Circulation: Cardiovascular Imaging