Credit: Journal of the American College of Cardiology (2023). DOI: 10.1016/j.jacc.2023.04.015
A new study led by researchers at Massachusetts General Hospital offers an explanation as to why light to moderate alcohol consumption may be associated with a lower risk of heart disease. For the first time, researchers found that alcohol, in light to moderate amounts, was associated with long-term reductions in stress signaling in the brain. This impact on the brain’s stress systems appeared to be largely responsible for the reduction in cardiovascular events observed in light to moderate drinkers who participated in the study. The findings are published in the Journal of the American College of Cardiology.
“We are not advocating the use of alcohol to reduce the risk of heart attacks or strokes because of alcohol’s other worrisome effects on health,” said senior author and cardiologist Ahmed Tawakol, MD, co-director of the Cardiovascular Imaging Research Center at Massachusetts General Hospital. . “We wanted to understand how light to moderate drinking reduces cardiovascular disease, as shown by multiple other studies. And if we could find the mechanism, the goal would be to find other approaches that could replicate or reduce the protective cardiac effects of alcohol.” induce without the adverse effects of alcohol.”
Previous epidemiological studies suggested that light to moderate alcohol consumption (1 drink per day for women and 1 to 2 drinks per day for men) is associated with a lower risk of cardiovascular disease. But it was not known whether alcohol conferred 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 who participated 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, even when those other factors were taken into account.
They then studied a subset of 754 subjects who had previously undergone PET/CT brain imaging (primarily for cancer surveillance) 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. When the researchers looked at the history of cardiovascular events of these individuals, they found 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,” says Tawakol.
It has long been known that alcohol decreases the amygdala’s response to threatening stimuli while people are drinking. The current study is the first to indicate that light to moderate alcohol consumption has longer-term neurobiological effects in dampening activity in the amygdala, which may have a significant downstream impact on the cardiovascular system.
“When the amygdala is too alert and vigilant, the sympathetic nervous system is heightened, which raises blood pressure and heart rate, and triggers the release of inflammatory cells,” explains Tawakol. “If the stress is chronic, the result is hypertension, increased inflammation and a significant risk of obesity, diabetes and cardiovascular disease.”
Finally, the researchers examined whether light/moderate alcohol would be even more effective at reducing heart attacks and strokes in people prone to a chronically higher stress response, such as those with a history of significant anxiety. They found that, within the sample of 50,000 patients, light to moderate drinking was associated with almost double the heart-protective effect in individuals with a history of anxiety compared to others.
But while light/moderate drinkers lowered their risk of cardiovascular disease, the study also showed that any amount of alcohol increased the risk of cancer. And with higher alcohol consumption — more than 14 drinks per week — the risk of a heart attack began to increase, while overall brain activity began to decline (which may be associated with negative cognitive health).
The authors concluded that research should focus on finding new interventions that reduce brain stress activity without the harmful effects of alcohol. The research team is currently studying the effect of exercise, stress-reducing interventions such as meditation and pharmacological therapies on stress-related neural networks and how they may provide cardiovascular benefits.
Co-authors include Kenechukwu Mezue and Michael T. Osborne.
More information:
Mezue Kenechukwu et al, Decreased stress-related neural network activity mediates the effect of alcohol on cardiovascular risk, Journal of the American College of Cardiology (2023). DOI: 10.1016/j.jacc.2023.04.015
Quote: Researchers discover why light to moderate drinking is linked to better heart health (2023, June 12) Retrieved June 13, 2023 from https://medicalxpress.com/news/2023-06-uncover-light-to-moderate -heart -health.html
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