Moderate Drinking May Boost Memory, Study Suggests

In the long run, a drink or two a day may be good for the brain.

Researchers found that moderate amounts of alcohol – amounts equivalent to a couple of drinks a day for a human – improved the memories of laboratory rats.

Such a finding may have implications for serious neurodegenerative diseases like Alzheimer's, said Matthew During, the study's senior author and a professor of molecular virology, immunology and cancer genetics at Ohio State University .

"There is some evidence suggesting that mild to moderate alcohol consumption can protect against diseases like Alzheimer's in humans,” said During. “But it's not apparent how this happens."

He and his colleague, Margaret Kalev-Zylinska, a postdoctoral researcher at the University of Auckland, in New Zealand, uncovered a neuronal mechanism that may help explain the link between alcohol and improved memory.

“We saw a noticeable change on the surface of certain neurons in rats that were given alcohol,” During said. “This change may have something to do with the positive effects of alcohol on memory.”

The researchers presented their findings at the annual Society for Neuroscience conference in Atlanta.

During and Kalev-Zylinska designed a special liquid diet for the rats. One formulation included a low dose of alcohol, comparable to two or three drinks a day for a human, while the other diet included a much higher dose of alcohol, comparable to six or seven drinks a day for a human. A third group of rats was given a liquid diet without alcohol. All animals were given their respective diets daily for about four weeks.

The researchers measured the rats' blood-alcohol levels three times throughout the study. Toward the end of the study, they subjected the rats to two different memory tasks.

For the first task, the rats were given several minutes to examine two identical, square plastic objects. After a certain amount of time, a researcher replaced one of the objects with a new, round object made of glass. The researchers measured the amount of time that each rat spent checking out the new object – an indication that the animal recognizes it as a new object.

Rats given low doses of alcohol spent about three times longer examining the new object than did rats on the alcohol-free diet. Rats given the high dose of alcohol spent equivalent amounts of time checking out both objects, suggesting that they were unable to differentiate the old object from the new one.

For the second task rats were placed in a box with two chambers separated by a door. One chamber was well-lit, while the adjacent chamber was dark. After placing a rat in the well-lit chamber and then lifting the door, the researchers timed how quickly the rats entered the dark chamber (rats are nocturnal, and naturally prefer dark spaces.) Once inside the dark chamber, the rat received a mild electric shock to its feet.