May 24, 2007
Imbibing a daily glass or wine or other alcoholic drink may slow the progression to Alzheimer's disease in people with mild cognitive impairment, a new study reports. The findings bolster earlier evidence that alcohol, in moderation, may be good for the brain. They appeared in Neurology, the scientific journal of the American Academy of Neurology.
Mild cognitive impairment, or MCI, is a transitional stage between normal aging and dementia. It is marked by notable memory problems or other cognitive losses, but those problems are not nearly as severe as the ones that occur in Alzheimer's disease. Each year, some seniors with MCI typically progress to dementia.
Researchers in Italy evaluated alcohol consumption and the incidence of mild cognitive impairment in 1,445 generally healthy people. Within that group they identified 121 people who had mild cognitive impairment, and then gave them regular exams to assess their progression to dementia over a three-and-a-half year period. The participants, age 65 to 84, were part of the Italian Longitudinal Study on Aging.
They found that people with mild cognitive impairment who had up to one drink of alcohol a day (or less), including up to one glass of wine, developed dementia at an 85 percent lower rate than people with mild cognitive impairment who did not drink alcohol or who drank more than one drink per day. However, no level of drinking (moderate or greater) appeared to protect against development of MCI in healthy individuals.
"While many studies have assessed alcohol consumption and cognitive function in the elderly, this is the first study to look at how alcohol consumption affects the rate of progression of mild cognitive impairment to dementia," said study authors Vincenzo Solfrizzi, MD, PhD, and Francesco Panza, MD, PhD, with the Department of Geriatrics at the University of Bari in Italy.
The investigators do not know why moderate alcohol consumption may protect against dementia. However, they cite other studies showing that alcohol may have a protective effect on blood vessels throughout the body, including those in the brain.
Moderate imbibing of alcohol is thought to be good for the heart and may help to prevent strokes. Some forms of dementia are caused by so-called 'mini-strokes' that gradually damage parts of the brain critical for thinking and memory. Although researchers believe that Alzheimer's is caused by a buildup of toxic forms of beta-amyloid, a protein found in the brain, it is very often accompanied by vascular disease that affects blood vessels in the brain as well.
Earlier studies support a protective role for alcohol. A large and rigorous study from Harvard in 2005, for example, found that nurses who had one drink a day, on average, performed better on memory tests than those who drank more heavily or not at all. They also tended to show less memory loss as the years passed. [See the article, "A Drink a Day May Keep the Mind Sharp."]
The current study did not find any association between higher levels of drinking, more than one drink per day, and the rate of progression to dementia. In other words, those who drank more than one drink per day did not have a decreased rate of progression from MCI to dementia.
Indeed, it is well documented that drinking alcohol in excess can damage the brain and many other parts of the body. The beneficial effects of alcoholic beverages on the brain seem to come from moderate drinking only.
The Fisher Center for Alzheimer's Research Foundation funds vital research into the underlying causes of Alzheimer's and the search for a cure. For more on ways to help keep the brain vital, visit www.ALZinfo.org.
V. Solfrizzi, MD, A. D'Introno, PhD, A. Am Colacicco, PhD: "Alcohol Consumption, Mild Cognitive Impairment, and Progression to Dementia." Neurology, Volume 68, pages 1790-1799, May 22, 2007.