Drinking alcohol in light to moderate quantities is linked to reductions in the brain’s stress activity and may be associated with a lower risk of heart disease, according to a new study.
The research, published on Monday in the Journal of the American College of Cardiology, found for the first time that light to moderate alcohol consumption – 1 drink per day for women and 1 to 2 drinks per day for men – is associated with long-term reductions in stress signaling in the brain.
This impact on the brain’s stress systems could account for the reductions in cardiovascular events seen in light to moderate drinkers, say researchers, including those from the Massachusetts General Hospital in the US.
“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,” study senior author and cardiologist Ahmed Tawakol said in a statement.
“We wanted to understand how light to moderate drinking reduces cardiovascular disease, as demonstrated by multiple other studies,” Dr Tawakol said.
By further understanding this mechanism, researchers hope to find other approaches that could replicate or induce alcohol’s protective cardiac effects without its adverse impacts.
While previous studies have suggested that light to moderate alcohol consumption is linked to a lower risk of heart disease, it has remained unclear whether alcohol by itself was inducing the benefits, or whether other factors seen in light/moderate drinkers such as socioeconomic status protected their hearts.
The new study assessed the data of over 50,000 individuals enrolled in the Mass General Brigham Biobank.
In its first part, 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 factors.
Researchers found that light/moderate alcohol consumption is linked to a substantial reduction in the risk of cardiovascular disease events, even after accounting for those other factors.
Then in a subset of 754 individuals who had undergone previous PET/CT brain scans, researchers assessed the effect of light/moderate alcohol consumption on resting stress-related brain activity.
In individuals who were light to moderate drinkers, the scans showed signs of reduced stress signaling in the amygdala brain region associated with stress responses compared to those who abstained from alcohol or drank less.
“We found that the brain changes in light to moderate drinkers explained a significant portion of the protective cardiac effects,” Dr Tawakol said.
The new study, according to researchers, is the first to indicate that light to moderate alcohol consumption has longer-term neurobiological effects in dampening activity in the amygdala.
“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 explained.
“If the stress is chronic, the result is hypertension, increased inflammation, and a substantial risk of obesity, diabetes, and cardiovascular disease,” he added.
When scientists examined whether light/moderate alcohol would be even more effective at reducing heart attacks and strokes in those prone to stress such as people with chronic anxiety, they found that it was linked to nearly double the cardiac-protective effect compared with others.
However, scientists cautioned that any amount of alcohol increases the risk of cancer, and at higher amounts, heart attack risk started to increase while overall brain activity started to decrease.
They hope future research would help find interventions that reduce the brain’s stress activity without the deleterious effects of alcohol.
