(USA TODAY) -- Up to one alcoholic drink a day may slow the development of dementia, including Alzheimer's, in seniors who already have mild memory problems, a study reports today.

Other reports have suggested that light to moderate drinking appears to protect healthy people from Alzheimer's, a progressive brain disease that afflicts 5 million people in the USA. But Italian researcher Vincenzo Solfrizzi says his is the first study to suggest that an alcoholic drink a day might help people with mild cognitive impairment (MCI), a condition that often precedes Alzheimer's.

What kind of alcoholic beverage is best? The study, which appears in today's Neurology, doesn't answer that question. But wine, and particularly red wine, contains natural chemicals called polyphenols that might protect the aging brain from Alzheimer's, Solfrizzi says.

The Italian team studied 1,445 healthy adults 65 and older and 121 who already had been diagnosed with MCI. People with the condition experience more than the usual age-related memory glitches, but they don't show other signs of dementia, such as impaired reasoning, says Solfrizzi, a geriatrician at the University of Bari in Italy.

For almost four years, the team kept track of the participants and had them take memory tests to reveal the development of MCI or outright dementia, including Alzheimer's.

Solfrizzi's team also asked the seniors if they were in the habit of drinking beer, wine or a drink with a shot of alcohol such as gin or vodka. People who responded yes were asked how much alcohol they consumed each day.

People who already had MCI at the start of the study appeared to gain protection from additional memory loss: The researchers found that drinking just half a glass of wine or less than a beer or some other kind of alcoholic drink a day seemed to decrease the rate of progression from MCI to full dementia, including Alzheimer's.

Many of the Italians in the study said they drank several glasses of red wine every day, Solfrizzi says. And the good news from other research is this: Moderate drinking -- one or even two glasses of wine a day -- just might help stave off dementia and other ailments such as clogged arteries and heart disease, says Gary Small, director of the University of California-Los Angeles Center on Aging.

But Small and other experts don't recommend that people start drinking just to gain a possible health benefit.

"You have to be very cautious," says Ron Petersen, a spokesman for the Chicago-based Alzheimer's Association and a neurologist at the Mayo Clinic in Rochester, Minn.

He says heavy drinking can actually cause memory loss and other serious health problems. And older people who may not be used to drinking risk getting tipsy and taking a serious fall.

"Even one glass can be too much," he says.

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