But don't raise your wine glass to celebrate yet. The study only included mice. It's too soon to know if the findings apply to people.
Still, the data deserves further study and support the theory that one daily drink of red wine for women and two for men "may help reduce" Alzheimer's risk, write the researchers.
They included Jun Wang, PhD, of the psychiatry department at New York's Mount Sinai School of Medicine.
Wang's team notes that alcohol has risks as well as benefits, and they're not recommending anyone to start drinking wine for Alzheimer's prevention.
Their study is due to appear in The FASEB Journal's November edition. "FASEB" stands for Federation of American Societies for Experimental Biology.
Wang's team studied female mice with genes that order the production of amyloid-beta protein, which has been linked to brain plaque in Alzheimer's patients.
The researchers split the mice into three groups. One group of mice got its drinking water spiked with red wine (Cabernet Sauvignon from California-grown grapes). Another group of mice had its drinking water mixed with ethanol that didn't come from red wine. The mice in the third group were teetotalers, drinking water with no alcohol.
The mice were free to drink as much as they wanted for seven months. None went on major benders.
The mice's average wine consumption equaled moderate consumption in humans, the researchers note. They defined moderate consumption as:
- 1 daily 5-ounce glass of wine for women
- 2 daily 5-ounce glasses for men
After seven months of sipping their designated drinks, the mice individually were placed in a maze and challenged to find their way out.
Those in the red wine group performed best. The mice in the ethanol group weren't better at mastering the maze than the teetotalers, the study shows.
That finding "suggests that ethanol, at concentrations comparable to Cabernet Sauvignon, does not significantly influence spatial memory," the researchers write.
Then Wang's team made the maze test tougher. They flipped the finish line to the opposite side of the maze. That way, the mice didn't find the finish line where they expected it to be.
The mice in the red wine group were quicker to adapt to that change. But the mice in the ethanol and water groups "performed poorly" in the new maze, note Wang and colleagues.
The Wine-Soaked Brain
The researchers checked the mice's brains for signs of amyloid-beta proteins.
The mice in the red wine group had the lowest levels of amyloid-beta proteins. No differences were seen in amyloid-beta levels in mice in the ethanol and water groups.
Lastly, the scientists doused Cabernet Sauvignon, at moderate levels for human consumption, on the building blocks of amyloid-beta protein.
Instead of making amyloid-beta, those chemical building blocks formed a different type of protein, the study shows.
The researchers caution that there is "no direct experimental evidence" that red wine or antioxidants called polyphenols in wine "beneficially influence" Alzheimer's disease.
That is, they're not making any Alzheimer's prevention promises for people.
Key Ingredient Unknown
What ingredient in red wine might explain the study's results? That's not clear.
Resveratrol, an antioxidant found in wine, has drawn attention in other research.
But in this experiment, resveratrol levels were 10 times lower than the minimum effective amount in past studies, note Wang and colleagues.
They call for more research to see if red wine and its polyphenol extracts are beneficial against Alzheimer's disease.
SOURCES: Wang, J. The FASEB Journal, November 2006. News relese, Mount Sinai School of Medicine.
By Miranda Hitti
Reviewed by Louise Chang, MD (en EspaC1ol)