A new study offers an explanation for why light-to-moderate alcohol consumption may be associated with lower risk of heart disease. For the first time, researchers found that alcohol, in light to moderate quantities, was associated with long-term reductions in stress signaling in the brain. This impact on the brain’s stress systems appeared to significantly account for the reductions in cardiovascular events seen in light to moderate drinkers participating in the study.
“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.” says senior author and cardiologist Ahmed Tawakol, MD.
Previous epidemiological studies have suggested that light to moderate alcohol consumption is associated with a lower risk of cardiovascular disease. But it was unknown whether alcohol was inducing cardiovascular benefits, or whether light/moderate drinkers’ health behaviors, socioeconomic status, or other factors protected their hearts.
The study, included more than 50,000 individuals enrolled in the Mass General Brigham Biobank. The first part of the study evaluated the relationship between light/moderate alcohol consumption and major adverse cardiovascular events after adjusting for a range of genetic, clinical, lifestyle, and socioeconomic confounders. The researchers found that light/moderate alcohol consumption was associated with a substantial reduction in the risk of cardiovascular disease events, even after accounting for those other factors.
Next, they studied a subset of 754 individuals who had undergone previous PET/CT brain imaging to determine the effect of light/moderate alcohol consumption on resting stress-related neural network activity.
The brain imaging showed reduced stress signaling in the amygdala, the brain region associated with stress responses, in individuals who were light to moderate drinkers compared to those who abstained from alcohol or who drank little. And when the investigators looked at these individuals’ history of cardiovascular events, they found fewer heart attacks and strokes in light to moderate drinkers. “We found that the brain changes in light to moderate drinkers explained a significant portion of the protective cardiac effects,” says Tawakol.
Finally, the investigators examined whether light/moderate alcohol would be even more effective at reducing heart attacks and strokes in people who are prone to a chronically higher stress response, such as those with a history of significant anxiety. They found that, within the 50,000-patient sample, light to moderate drinking was associated with nearly double the cardiac-protective effect in individuals with a history of anxiety compared with others.
The authors concluded that research should focus on finding new interventions that reduce the brain’s stress activity without the deleterious effects of alcohol.
Kenechukwu Mezue, Michael T. Osborne, Shady Abohashem, Hadil Zureigat, Charbel Gharios, Simran S. Grewal, Azar Radfar, Alexander Cardeiro, Taimur Abbasi, Karmel W. Choi, Zahi A. Fayad, Jordan W. Smoller, Rachel Rosovsky, Lisa Shin, Roger Pitman, Ahmed Tawakol. Reduced Stress-Related Neural Network Activity Mediates the Effect of Alcohol on Cardiovascular Risk. Journal of the American College of Cardiology, 2023; 81 (24): 2315 DOI: 10.1016/j.jacc.2023.04.015
Massachusetts General Hospital. “Researchers uncover why light-to-moderate drinking is tied to better heart health: The findings could help in identifying new interventions that reduce the brain’s stress activity without the negative health effects of alcohol.” ScienceDaily. ScienceDaily, 12 June 2023. <www.sciencedaily.com/releases/2023/06/230612200347.htm>.
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