But it also can flush it of toxins, including those associated with Alzheimer’s disease and other forms of dementia.
Study leader Dr Maiken Nedergaard said: “This study shows for the first time that low doses of alcohol are potentially beneficial to brain health, improving the brain’s ability to remove waste.”
Research at the University of Rochester Medical Center in the US focused on the glymphatic system, the brain’s cleaning process.
It showed how cerebral spinal fluid is pumped into brain tissue and flushes away waste – including the proteins beta-amyloid and tau.
These are associated with Alzheimer’s disease and other forms of dementia. Previous studies have found that the glymphatic system is more active while we sleep, can be damaged by stroke and trauma, and improves with exercise.
The new research looked at the impact of both acute and chronic alcohol exposure and was conducted in mice. The mice were given low, intermediate, and high doses of alcohol.
When they studied the brains of animals exposed to high levels of alcohol over a long period, scientists observed high levels of a molecular marker for inflammation and impairment of cognitive abilities and motor skills.
Yet mice exposed to low levels of alcohol consumption, equivalent to approximately two-and-a-half small glasses of wine per day for humans, showed less inflammation in the brain.
Their glymphatic system was also more efficient in moving cerebral spinal fluid through the brain and removing waste, compared with “teetotal” mice.
Mice who drank low amounts also performed identically to the “teetotal” mice in cognitive and motor tests.
Dr Nedergaard added: “Prolonged intake of excessive amounts of ethanol is known to have adverse effects on the central nervous system.
“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 to explain why this occurs.”
The findings are published in the journal Scientific Reports.