Moderate alcohol intake, defined as no more than 1 alcoholic drink for women and 2 for men per day, has been associated with a lower risk of dying from cardiovascular disease when compared with individuals who abstain from drinking or partake in excessive drinking, according to a new study being presented at the American College of Cardiology's 70th Annual Scientific Session. According to the authors of the study, the finding suggests that reducing stress-related brain signals can be heart protective, and other therapies with the same effects but fewer adverse effects than alcohol should be pursued.
“We found that stress-related activity in the brain was higher in nondrinkers when compared with people who drank moderately, while people who drank excessively—more than 14 drinks per week—had the highest level of stress-related brain activity,” said Kenechukwu Mezue, MD, a fellow in nuclear cardiology at Massachusetts General Hospital, in a press release. “The thought is that moderate amounts of alcohol may have effects on the brain that can help you relax, reduce stress levels and, perhaps through these mechanisms, lower the incidence of cardiovascular disease.”
While a connection between stress and heart disease is widely accepted, there has been limited research on how modifying stress levels may improve and protect heart health, according to the authors of the study. A related study by the same team found that exercise had a similar effect on brain activity as well as on the incidence of cardiovascular disease and events.
“The current study suggests that moderate alcohol intake beneficially impacts the brain-heart connection. However, alcohol has several important side effects, including an increased risk of cancer, liver damage and dependence, so other interventions with better side effect profiles that beneficially impact brain-heart pathways are needed,” Mezue said in the release.
The researchers gathered data from the Mass General Brigham Biobank health care survey of 53,064 participants, of which 59.9% were women and the average age was 57.2 years. Alcohol intake was self-reported and was classified as low (<1 drink/week), moderate (1-14 drinks/week), or high (>14 drinks/week). Major adverse cardiovascular events, including heart attack, stroke, or related hospitalizations, were determined using diagnostic codes. Of these patients, 752 underwent 18F-fluorodeoxyglucose positron emission tomography, which can show areas in the brain that have increased activity, allowing the researchers to objectively measure activity in regions of the brain known to be associated with stress.
Fifteen percent of the participants experienced a major adverse cardiovascular event, occurring in 17% in the low alcohol intake group, and 13% in the moderate alcohol intake group. In adjusted analysis, individuals reporting moderate alcohol intake were found to have a 20% lower chance of having a major event compared to the low alcohol intake cohort and had lower stress-related brain activity. This association remained significant after controlling for demographic variables, cardiovascular risk factors, socioeconomic variables, and psychological factors.
“Previous studies by our group and others have shown a robust association between heightened amygdalar activity and a higher risk of major adverse cardiovascular outcomes, such as heart attack, stroke, or death. In the current study, path analyses showed that the link between moderate alcohol intake and lowered cardiovascular event risk is significantly mediated though reductions in amygdalar activity,” Mezue said in the release.
The current study is limited due to the self-reporting of alcohol intake based on the average consumption of drinks per week, according to its authors. Further, the data is from a single center, and each participant in the imaging sub-study only received a single brain scan. Further study would be needed to show that the observed reductions in brain activity are the direct result of moderate alcohol intake through repeated brain scans and more detailed alcohol intake assessments over time.
Alcohol in moderation may help the heart by calming stress signals in the brain [news release]. EurekAlert; May 6, 2021. Accessed May 6, 2021. https://www.eurekalert.org/pub_releases/2021-05/acoc-aim050421.php