Drinking alcohol in moderate amounts may improve the ability to create and maintain memories properly, according to a new study from the University of Auckland in New Zealand and Ohio State University in Columbus, Ohio.
Published in the September issue of the Journal of Neuroscience, the research found that rats that drank alcohol in moderation seemed to have superior cognitive skills when compared to non-drinking and heavy-drinking rats, in ways that may occur similarly in humans. "We do believe these results are relevant to humans," said researcher Matthew During, a molecular pathologist working in Ohio and New Zealand, who co-wrote the study with Maggie Kalev-Zylinska, a professor at the University of Auckland's department of Molecular Medicine and Pathology.
According to the study text, despite alcohol being extensively studied and widely consumed, "the biological processes underlying its beneficial effects on memory remain unknown." Furthermore, studies on animals into the effects of ethanol intake on learning and memory are limited.
The researchers separated rats into groups of six. One group was fed a standard diet and just water. Another group was served water with an ethanol content of 2.5 percent, and the third was served water at 5 percent ABV. The latter two groups represented moderate and heavy drinking, respectively, During said. The blood alcohol level by body weight for the moderate rats never exceeded the legal driving limit for humans in Australia, the study said.
After five weeks, During and Kalev-Zylinska began a series of behavior and memory tests. One test was to place the rat by itself in a cage. Two different-shaped, colorless objects were then put into the cage and the rat was given time to "explore" the objects before each shape was removed. Three hours later one of the previous shapes was put back into the cage, along with a new shape. The ability of the rat to both recognize the old shape and spend longer time with the new object was recorded.
In another test, the rats were put in a cage divided into two sections. One section, where the rats were placed, was dimly lit; the other section was completely dark. Instinctually, a rat will move quickly into the darkened area, which these rats did, but once in the dark area, the rats received a mild shock. The test was repeated, 24 hours later, and the scientists observed the rats' ability to weigh their instinct to run for the dark versus their memories of being shocked.
In both sets of tests, the moderately drinking rats performed best, indicating the greatest cognitive ability. This group was best at examining the new object placed in the cage in the first test, and spent more time contemplating the move into the dark area in the second test. The rats that didn't drink performed second best, followed by the heavy-drinking rats.
At the end of nine weeks, the rats' brains were examined. While from the early tests the researchers believe that moderate alcohol most likely aided memory through its interaction with brain receptors, the results are still inconclusive. However, upon examination, the brains of the heavy-drinking rats showed measurable levels of damage, which would have impaired the rodents' ability on many levels. "In contrast to our model of heavy drinking, feeding rats with low amounts of ethanol did not produce deleterious neurological effects at the behavioral, cellular or molecular levels," wrote the authors of the study.
During said that the main point of the research is that light to moderate consumption of wine each day is not associated with long-term memory impairment. In fact, he added such responsible drinking may actually protect the brain, not just with its memories, but perhaps also against diseases such as Alzheimer's.