Low levels of alcohol consumption can tamp down inflammation in the brain and help clear away toxins, including those associated with Alzheimer’s disease. This shows a new study conducted in mice, which appears in the journal Scientific Reports.

“Prolonged intake of excessive amounts of ethanol is known to have adverse effects on the central nervous system. However, 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,” says professor Maiken Nedergaard Center for Translational Neuromedicine at the University of Copenhagen and co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center (URMC) and lead author of the study.

The finding adds to a growing body of research that point to the health benefits of low doses of alcohol. While excessive consumption of alcohol is a well-documented health hazard, many studies have linked lower levels of drinking with a reduced risk of cardiovascular diseases as well as a number of cancers.

Nedergaard’s research focuses on the glymphatic system, the brain’s unique cleaning process that was first described by Nedergaard and her colleagues in 2012. They showed how cerebral spinal fluid (CSF) is pumped into brain tissue and flushes away waste, including the proteins beta amyloid and tau that are associated with Alzheimer’s disease and other forms of dementia.

The effects of alcohol on the brain

The new study, which was conducted in mice, looked at the impact of both acute and chronic alcohol exposure. When they studied the brains of animals exposed to high levels of alcohol over a long period of time, the researchers observed high levels of a molecular marker for inflammation, particularly in cells called astrocytes which are key regulators of the glymphatic system. They also noted impairment of the animal’s cognitive abilities and motor skills.

Animals that were exposed to low levels of alcohol consumption, analogous to approximately 2½ drinks per day, actually showed less inflammation in the brain and their glymphatic system was more efficient in moving CSF through the brain and removing waste, compared to control mice who were not exposed to alcohol. The low-dose animals’ performance in the cognitive and motor tests was identical to the controls.

“The data on the effects of alcohol on the glymphatic system 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,” said Nedergaard. “Studies have shown that low-to-moderate alcohol intake is associated with a lesser risk of dementia, while heavy drinking for many years confers an increased risk of cognitive decline. This study may help explain why this occurs. Specifically, low doses of alcohol appear to improve overall brain health.”

Additional co-authors include Iben Lundgaard, Wei Wang, Allison Eberhardt, Hanna Vinitsky, Benjamin Reeves, Sisi Peng, Nanhong Lou, and Rashid Hussein with URMC. Nedergaard maintains research labs at both URMC and the University of Copenhagen in Denmark. The study was funding with support from the Department of Navy’s Office of Naval Research and the NINDS and NIA.

Please find the study "Beneficial effects of low alcohol exposure, but adverse effects of high alcohol intake on glymphatic function" here.