People who have one to two alcoholic drinks a day are often at a lower risk of developing Alzheimer’s disease and dementia than their non-drinking peers, researchers concluded after analyzing 44 studies about moderate alcohol intake and its effect on the heart and the brain.

More than half of the studies – all published since 1990 and conducted on humans over the age of 60 and animals – found benefits to sipping a regular glass of wine, beer or spirits. Only a handful of the studies, all reviewed in July, 2007, by a consortium of seven American researchers in Chicago, made negative links.

Lead author Michael Collins of Loyola University Chicago’s school of medicine says the report helps physicians and the public understand that moderate alcohol consumption may benefit not only the heart but the brain as well. “Alcohol in these two different organs is triggering a protective state that uses similar biochemical pathways,” he says of findings in the report to be published in the February, 2009, issue of Alcoholism: Clinical and Experimental Research. “With the brain, we’re trying to see whether we can understand those pathways.”

Research that focuses on the effects of moderate alcohol intake on the brain is slowly emerging, Dr. Collins says. While no one knows exactly why benefits exist, the studies offer a couple of theories. One is that slight exposure to alcohol whips cells into shape, creating a protective layer in the brain made of proteins that can prevent the onset of dementia and other forms of cognitive decline. Another theory plays on how the well-known cardiovascular benefits of moderate alcohol intake – such as the way it causes muscles and blood streams to relax – can protect against small strokes, which often lead to dementia.