BOSTON — Alcohol is undeniably unhealthy in a variety of ways, but studies continue to find that light-to-moderate drinking has a connection to improved heart health. This apparent health benefit tied to alcohol has confused doctors and scientists alike for quite some time. Now, new research out of New England is finally offering up a viable explanation. For the first time ever, researchers discovered that consuming alcohol in moderation may lead to long-term reductions in stress signaling within the brain.
This positive impact on the brain’s stress systems appears to significantly account for reductions in cardiovascular events among light-to-moderate drinkers participating in this study. Before you run out and pick up a six-pack, study authors caution that these findings shouldn’t encourage anyone to drink “for their health.”
“We are not advocating the use of alcohol to reduce the risk of heart attacks or strokes because of other concerning effects of alcohol on health,” says senior author and cardiologist Ahmed Tawakol, MD, co-director of the Cardiovascular Imaging Research Center at Massachusetts General Hospital, in a media release. “We wanted to understand how light to moderate drinking reduces cardiovascular disease, as demonstrated by multiple other studies. And if we could find the mechanism, the goal would be to find other approaches that could replicate or induce alcohol’s protective cardiac effects without the adverse impacts of alcohol.”
How does alcohol change the brain?
Earlier epidemiological studies already revealed that light-to-moderate alcohol consumption (one drink per day for women and one to two drinks per day for men) has a link to a lower risk of cardiovascular disease. However, it was still unclear if alcohol was inducing any cardiovascular benefits, or if perhaps light drinkers’ health behaviors, socioeconomic status, or other factors were protecting their hearts.
So, this project, led by Kenechukwu Mezue and Michael Osborne, encompassed over 50,000 people enrolled in the Mass General Brigham Biobank. The first portion entailed evaluating the relationship between light-to-moderate alcohol consumption and major adverse cardiovascular events. Researchers were sure to adjust for a range of genetic, clinical, lifestyle, and socioeconomic confounders.
Ultimately, this process led to the discovery that light or moderate alcohol consumption had an association with a substantial reduction in the risk of cardiovascular disease events.
Next, study authors analyzed a subset of 754 individuals who had undergone previous PET/CT brain imaging (primarily for cancer detection) in an effort to gauge the effect of light-to-moderate alcohol consumption on resting stress-related neural network activities.
Those brain images showed reduced stress signaling in the amygdala, the brain region thought to be associated with stress responses, among individuals who were light or moderate drinkers compared to others who abstained from alcohol altogether or drank very little. Additionally, when investigators looked at these individuals’ history of cardiovascular events, they noted fewer heart attacks and strokes among light to moderate drinkers.
“We found that the brain changes in light to moderate drinkers explained a significant portion of the protective cardiac effects,” Dr. Tawakol adds.
Modern medicine has long understood that alcohol reduces the amygdala’s reactivity to threatening stimuli. This latest research, though, is the first ever to suggest that light-to-moderate alcohol consumption has longer-term neurobiological effects in dampening activity in the amygdala, which could result in a significant downstream impact on the cardiovascular system.
“When the amygdala is too alert and vigilant, the sympathetic nervous system is heightened, which drives up blood pressure and increases heart rate, and triggers the release of inflammatory cells,” Dr. Tawakol explains. “If the stress is chronic, the result is hypertension, increased inflammation, and a substantial risk of obesity, diabetes, and cardiovascular disease.”
Drinking still increases the risk of certain diseases
Finally, the research team assessed if light drinking would be even more effective at reducing heart attacks and strokes among people who are especially prone to a chronically higher stress response. For example, people with a history of significant anxiety. Within the 50,000-patient sample, light-to-moderate drinking was indeed associated with nearly double the cardiac-protective effect in individuals with a history of anxiety in comparison to other people.
Still, while light or moderate drinkers lowered their risk for cardiovascular disease, any amount of alcohol was also shown to increase cancer risk. Also, at higher levels of alcohol consumption (more than 14 drinks a week), heart attack risk began to increase and overall brain activity started to decrease (potentially associated with adverse cognitive health).
In conclusion, researchers say efforts moving forward should focus on finding new interventions that reduce the brain’s stress activity without the additional deleterious effects of alcohol. Study authors are currently analyzing the effect of exercise, stress-reduction interventions like meditation, and pharmacological therapies on stress-associated neural networks and how they could spark cardiovascular benefits.
The study is published in the Journal of the American College of Cardiology.
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