Researchers shed light on how low levels of drinking might improve brain health.
In a mouse study, scientists from the University of Rochester Medical Center (URMC) in New York found that drinking the equivalent to around 2.5 alcoholic drinks per day could reduce brain inflammation.
It was also found to increase the function of the glymphatic system, which is responsible for removing waste products from the brain.
High alcohol exposure, however, was found to impair glymphatic function and increase brain inflammation.
Lead study author Dr. Maiken Nedergaard, of the Center for Translational Neuromedicine at URMC, and colleagues recently reported their findings in the journal Scientific Reports.
It should come as no surprise that excess alcohol intake can harm health. In fact, the World Health Organization (WHO) report that alcohol is a contributor to "more than 200 health conditions" and causes around 3.3 million deaths across the globe each year.
Increasingly, however, research has suggested that a little alcohol may do us good.
A study reported by Medical News Today last year, for example, suggested that moderate drinking could reduce the risk of diabetes, while other research linked moderate alcohol intake with better cognitive functioning.
The new study provides further evidence of the potential brain benefits of moderate drinking, after finding that a couple of drinks every day could help to clear the brain of toxins.
Glymphatic function improved
The researchers came to their findings by assessing the effects of acute and chronic alcohol exposure on the glymphatic system of mice.
First described by Dr. Nedergaard and colleagues in 2012, the glymphatic system is a brain-cleaning process wherein cerebral spinal fluid is "pumped" into the brain, where it removes potentially harmful waste products.
These waste products include beta-amyloid and tau proteins, the accumulation of which are a hallmark of Alzheimer's disease.
The researchers found that when the rodents were exposed to high doses of alcohol over a long period, they demonstrated an increase in inflammatory markers. This was especially noticeable in astrocytes, or cells that help to control glymphatic function.
Additionally, high alcohol exposure was found to impair cognitive functioning and motor skills in the mice.
However, the team found that mice that were given "low" doses of alcohol — which, in this study, was the equivalent of consuming around 2.5 alcohol beverages per day — not only demonstrated a reduction in brain inflammation, but their glymphatic function was also improved, compared with a control group that was not exposed to alcohol.
"The data on the effects of alcohol on the glymphatic system," explains Dr. Nedergaard, "seemingly matches the J-shaped model relating to the dose effects of alcohol on general health and mortality, whereby low doses of alcohol are beneficial, while excessive consumption is detrimental to overall health."
"[...] in this study we have shown for the first time that low doses of alcohol are potentially beneficial to brain health, namely it improves the brain's ability to remove waste."
Dr. Maiken Nedergaard
She adds that a number of studies have associated low to moderate alcohol consumption with a lower risk of dementia. "This study may help explain why this occurs," Dr. Nedergaard says. "Specifically, low doses of alcohol appear to improve overall brain health."