A new study challenges the widely held belief that light drinking of alcohol may be good for your heart.
Researchers analyzed more than 50 studies that examined drinking habits and heart health in more than 260,000 people.
They found that those with a form of a gene tied to lower levels of drinking generally had healthier hearts. The gene affects how a person's body breaks down alcohol, resulting in unpleasant symptoms such as nausea and facial flushing. Having this variant has been shown to lead to lower drinking over the long term, the researchers explained.
On average, people with the gene had lower blood pressure, lower body-mass index (an estimate of body fat based on height and weight) and a 10 percent lower risk of heart disease.
The results suggest that cutting alcohol intake -- even for light-to-moderate drinkers -- benefits heart health, according to the authors of the study in the July 11 issue of the BMJ.
"While the damaging effects of heavy alcohol consumption on the heart are well-established, for the last few decades we've often heard reports of the potential health benefits of light-to-moderate drinking," study senior author Juan Casas, a professor of epidemiology at the London School of Hygiene & Tropical Medicine, said in a university news release. "However, we now have evidence that some of these studies suffer from limitations that may affect the validity of their findings.
"In our study, we saw a link between a reduced consumption of alcohol and improved cardiovascular health, regardless of whether the individual was a light, moderate or heavy drinker," Casas said. The study could only show an association between the two, however, it couldn't prove cause-and-effect.
Further large-scale gene studies are needed to confirm these findings, the researchers said.
"Studies into alcohol consumption are fraught with difficulty, in part because they rely on people giving accurate accounts of their drinking habits," Dr. Shannon Amoils, senior research advisor at the British Heart Foundation, said in the news release "Here the researchers used a clever study design to get round this problem by including people who had a gene that predisposes them to drink less."
"The results reinforce the view that small to moderate amounts of alcohol may not be healthy for the heart, although the study would need to be repeated in a larger group of people for definitive results," Amoils said.
However, Dr. Suzanne Steinbaum, a preventive cardiologist at Lenox Hill Hospital in New York City, issued a word of caution about the latest findings.
"In light of the many trials revealing the [antioxidant] polyphenols found in red wine as being beneficial for cardiovascular disease, one must look at this trial with a critical eye," Steinbaum said. "It is clear that the patients with this genetic variant have a reduction in alcohol intake, but it is unclear if this in itself is the factor improving [their] cardiovascular outcomes."