Drinking red wine may not put the brain at an added risk of alcohol-induced brain damage, according to recent research from Portugal. The study, published June 8 in the journal Neuroscience, found that rats that were given heavy amounts of red wine did not suffer memory damage when compared to rats that were given pure alcohol. The scientists said that humans may experience similar benefits from drinking red wine as well, even though regular, heavy consumption is not recommended.
"In biomedical research, we must be extremely cautious once establishing homologies between results obtained in laboratory animals and in man," said the study's co-author, Manuel Paula-Barbosa, a researcher at the department of anatomy at the University of Porto. "However, on the grounds of the so-called 'French paradox,' known to be underpinned by the same antioxidant properties of red wine, there are good reasons to believe that our experimental findings in the rat brain are likely to be observed in humans."
The researchers pointed out that there are no prior experimental studies about the effect of long-term, heavy red wine consumption on the memory. The heavy and chronic consumption of alcohol, a well-documented neurotoxin, is known to damage parts of the brain, especially the hippocampus, which is responsible for the ability to navigate. However, the scientists theorized that if compounds found naturally in red wine provide protection to other parts of the body (for example, the polyphenol resveratrol is associated with helping rats maintain a healthy weight), then the beverage may also protect parts of the brain as well.
"Our hypothesis is that the antioxidant polyphenols of wine can protect neurons from the damaging effect of alcohol contained in this beverage," wrote the researchers, "thereby slowing or preventing the development of functional disturbances [in the brain]."
The scientists tested their hypothesis using 36 six-month-old rats, and separated them into three groups of 12. One group was offered only water and standard rat chow, the other received water at 20 percent alcohol by volume, and the third group was given only red wine, also at 20 percent ABV, provided by Quinta do Vale Meão from the Douro region of Portugal. Red wines normally contain about 14 percent alcohol, but the winery provided a wine with a much higher-than-normal alcohol content to help simulate the effects of heavy, chronic consumption and provide a level comparable to the alcohol-only group of rats.
After several weeks, the scientists tested the rats' hippocampus ability using what's called a Morris water maze. This maze is simply a big tub of water, with a single, hidden escape hatch somewhere below the surface. Visual clues are placed in the maze, and the vicinity of these to the exit is never changed.
The hippocampus is the area of the brain where oxidative stress occurs first; as with Alzheimer's disease, damage to the hippocampus is demonstrated by one's difficulty to find their way to familiar locations. As for the rats in the maze, when placed in the water, they swim around, trying to locate the exit. Since the rat is only relying on eyesight to find its way out of the maze, if the hippocampus is operating properly, the rat can find the exit quickly, regardless of where in the maze it is placed.
Before the rats were put on their respective diets, it took about one minute for rats from all three groups to find their way out of the maze. After their diets began, the rodents were put into the maze once a month to allow the scientist to observe experience-based memory reactions instead of an activity hard-wired through daily repetition. Over time, the scientists found that rats from the red-wine group performed consistently as well as those drinking water only. By the final stages of the experiment, six months later, rats on the alcohol-only solution took about twice as long to find the exit, an average of 25 seconds. The researchers also confirmed alcohol-related hippocampus damage in the latter group of rats through dissections performed at the end of the experiment. Red-wine-drinking rats showed no similar damage, and neither did the group that drank only water.
The scientists believe that the high levels of antioxidants found in red wine were responsible for protecting the brain cells of the hippocampus. "[These] molecules form a protective shield that defends cell organelles from the aggressive actions of ethanol oxidant effects," said Paula-Barbosa.
However, the scientists do not recommend such heavy drinking for humans, as drinking a wine so high in alcohol, all day long, as the rats did, could cause numerous other health problems. In addition, the renal system of rats is better equipped than that of humans to deal with such consistently high alcohol exposure. Nonetheless, the results provide "further evidence supporting the existence of beneficial antioxidant activity brought about by red wine when moderately consumed," wrote the authors of the study.