For decades, studies have linked light and moderate drinking to improved cardiovascular health. Modest amounts of alcohol have been found to increase HDL cholesterol (the "good" kind) and inhibit the formation of blood clots that can cause heart attack and stroke. But a recent study, published in June in the Journal of the American College of Cardiology, claims we've been missing a crucial piece of the scientific puzzle. Maybe it's all in our minds, so to speak.
Researchers at Massachusetts General Hospital have found that drinking lowers stress signaling in the brain—particularly in the amygdala—which is a key driver of cardiovascular problems. The study found that light or moderate drinking was associated with a 21.4 percent reduced risk of major adverse cardiovascular events compared to no or minimal drinking.
Although previous research has described how alcohol decreases amygdala activity in the short term, this is the first study to demonstrate alcohol's long-lasting beneficial effect on brain stress—and to link that effect to cardiovascular health.
The brain-heart connection
The study proposes a new mechanism by which modest amounts of alcohol may improve heart health. Chronic stress increases brain activity in the amygdala, a part of the brain strongly connected to fear and anxiety, which leads to harmful inflammation and other negative effects. High blood pressure, obesity, diabetes and cardiovascular disease (including heart attack and stroke) are among the ultimate possible effects of this heightened stress signaling. By reducing resting stress-associated neural network activity, alcohol consumption lowers the risk of major adverse cardiovascular events.
Anxiety is associated with higher baseline levels of stress signaling, and light and moderate drinkers with a history of anxiety experienced nearly twice the benefit of alcohol compared to drinkers without anxiety. Dr. Michael Osborne (a cardiologist at Mass General) and Dr. Kenechukwu Mezue (a clinical fellow at the Yale School of Medicine), co-lead authors of the study, told Wine Spectator that while this finding supports their hypothesis that alcohol reduces stress signaling and improves heart health, it "does not imply that those with anxiety should be encouraged to drink more alcohol."
The methods
The researchers used data from the Mass General Brigham Biobank, a large-scale project that has collected health information on more than 135,000 participants so far, studying how genes, lifestyle and other factors affect people's health and contribute to disease. For this study, the team examined data on more than 50,000 participants, just over half of whom were light or moderate drinkers (defined as consuming 1 to 14 drinks per week for both women and men). From this large group of subjects, the researchers collected brain imaging data from a subset of around 750 individuals to look for a link between light or moderate drinking, reduced stress-related neural network activity and improved cardiovascular health.
The researchers controlled for many potentially confounding variables, including socioeconomic status, genetics, lifestyle factors (such as smoking and exercise habits) and health conditions (including high blood pressure, high cholesterol and diabetes). The link between light and moderate drinking, reduced brain stress and improved cardiovascular health remained significant even after controlling for these variables. They also controlled for potential "sick quitter" bias, the possibility that non-drinkers are people who no longer drink alcohol because of past alcohol-related health problems.
The study didn't differentiate between types of alcohol consumed, so it's unclear whether people who mostly drink wine would have different outcomes than people who drink beer or spirits. The research did not determine the amount of alcohol that maximized health benefits, and it is an observational study, meaning it can't establish causality.
What does it mean for wine drinkers?
The study is exciting news for light and moderate wine drinkers, particularly those concerned about their heart. By establishing a new pathway by which alcohol may lower the risk of cardiovascular issues, the research adds to the evidence that a glass or two of wine a day can be part of a healthy lifestyle—and may have significant health benefits. Even as alcohol's potential health upsides have been questioned by some researchers, this study sharpens our picture of alcohol's potentially beneficial effects.
The researchers stress that their results shouldn't be taken as encouragement to start drinking if you don't already. They caution that any alcohol consumption is associated with health risks, particularly the risk of developing certain cancers, and they emphasize the destructive effects of high consumption. For that reason, they call for further study of "an intervention that acts similarly on [brain stress signaling] without alcohol's potential detrimental effects," such as exercise, yoga and meditation.
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