Alcohol doesn't often get billed as brain food, but new research suggests that…

Alcohol doesn't often get billed as brain food, but new research suggests that booze offers at least one cerebral benefit. It may reduce aging drinkers’ risk of developing Alzheimer's disease and other forms of dementia.

Although extreme alcohol consumption kills brain cells, there's contradictory evidence about whether long-term drinking has permanent effects on cognitive abilities such as reasoning and memory. Prolonged, excessive drinking can lead to liver disease cirrhosis and may contribute to breast cancer risk, however. Drinking is also responsible for many accidental injuries and deaths.

Nevertheless, alcohol in moderation promotes cardiovascular health by boosting concentrations of good cholesterol and inhibiting the formation of dangerous blood clots. Additional compounds in red wine seem to benefit the heart and blood vessels. Drinking also appears to guard against macular degeneration, an incurable eye disease.

Now, the brain joins the list of organs that seem to benefit from alcohol.

From 1990 to 1999, Monique M.B. Breteler and her colleagues at the Erasmus Medical Centre in Rotterdam, the Netherlands, observed 5,395 individuals age 55 and older who didn't initially show signs of dementia. Of these participants, 1,443 “moderate drinkers" reported having one to three alcohol beverages of some sort each day, while 2,674 said they consumed less than one drink and 165 acknowledged having four or more drinks per day. Another 1,113 participants abstained altogether.

Over an average follow-up period of 6 years, 146 participants developed Alzheimer's disease and another 51 got some other form of age-related dementia. That put the overall risk for dementia at 3.7 percent. The risk was about 4 percent among non-drinkers, light drinkers, and heavy drinkers, but only 2.6 percent of the moderate drinkers developed dementia.

Once the researchers adjusted their data to account for participants’ sex, age, weight, blood pressure, use of tobacco, and other factors that influence dementia, moderate drinkers showed only 58 percent the risk of dementia calculated for non-drinkers, Breteler's team reported.

Moderate drinkers had an even more marked decrease in vascular dementia, a condition in which blockages in blood vessels in the brain cause recurring, minor strokes that gradually erode cognitive ability. The researchers hypothesize that since vascular disorders are linked to dementia in elderly people, alcohol's benefits to blood vessels might indirectly sustain brain function.

Jean-Marc Orgagozo, a neurological epidemiologist at the University of Bordeaux in France hails the study. He and his colleagues have found that French wine drinkers over the age of 65 have a reduced risk of dementia. The new research supports that finding, shows that beer and hard liquor—not just wine—are protective, and establishes the effect in somewhat younger people, he says.

John R. Copeland, a psychiatrist who's retired from the University of Liverpool in England, calls the Dutch finding "very interesting but not unexpected." Although Copeland's research suggested that heavy, long-term drinking reduces cognitive ability in elderly men, people who show benefits in the new study consumed alcohol in more modest, "therapeutic quantities,” he says.

However, Orgogoze questions exactly what quantity constitutes a happy-hour medium. His own past research suggests three to four drinks per day are required to help ward off dementia. The lower threshold for benefit in the Dutch study may reflect participants’ under-reporting of alcohol consumption in a country that, unlike France, attaches a stigma to drinking, Orgogozo says.

According to the passage, the term ‘therapeutic quantities’ is used to indicate that