Think drinking one to two glasses of red wine a day is good for the heart? Think again. A new study flies in the face of a widely held scientific belief that light to moderate alcohol consumption helps keep drinkers healthy.
Researchers from the University of Pennsylvania, University College London and the London School of Hygiene and Tropical Medicine found that reducing alcohol consumption even in light drinkers may lead to better heart health, a lower risk of coronary diseases, better blood pressure and better chances of keeping a healthy weight. The study was published in Thursday's issue of the British Medical Journal.
"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," says Juan P. Casas, lead researcher and professor of epidemiology in a statement. "Assuming the association is causal, it appears that even if you're a light drinker, reducing your alcohol consumption could be beneficial for your heart."
The researchers conducted a meta-analysis of 50 studies that examined the drinking habits of more than 260,000 people and found that subjects who carried a genetic variant that was linked to lower alcohol consumption drank 17% less alcohol than those who didn't have the gene and were 78% less likely to binge-drink. The researchers also found that these individuals had 10% lower risk of cardiovascular problems, lower blood pressure and a lower body mass index.
People with the alcohol dehydrogenase 1B gene are known to have faster alcohol breakdown, leading to sensitive reactions such as facial flushing and nausea. This, the researchers explain, have led to overall lower consumption in individuals with this gene. In contrast to most studies that have relied on self-reporting to measure individuals' drinking habits over time, the study used the presence of this gene to indicate lower alcohol consumption.
"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," says Dr. Shannon Arnoils, senior research advisor at the British Heart Foundation, which funded the study.
Critics agree and, although they say the new findings are worth a second glance, the debate on whether a glass or two of an alcoholic beverage isn't likely to end soon. Particularly significant is the study's statistical nature, which critics point out does not explain why individuals who have the alcohol dehydrogenase 1B gene are healthier than those who don't.
"People with genes for alcohol intolerance may have other unmeasured behaviors or traits that reduce heart disease," says Tim Specter, epidemiologist at King's College London. "A good example might be if they also had different gut microbes which prevented heart disease."
