July 13, 2009 (Vienna, Austria) -- A drink or two a day may help to protect older people from developing dementia.
But once people 75 and older already have mild cognitive impairment, or have been diagnosed with memory loss, any amount of alcohol accelerates the rate of memory decline, says researcher Kaycee Sink, MD, of the Wake Forest University School of Medicine in Winston-Salem, N.C.
Many studies have shown that moderate alcohol intake, especially wine, is associated with a lower risk of dementia in healthy middle-aged adults. But it was not known whether this association is also true for older adults or for those with mild cognitive impairment, Sink tells WebMD.
For the new study, the researchers followed 3,069 people 75 and older for six years. At the start of the study, 482 of them had been diagnosed with mild cognitive impairment.
The study showed that people who drank one to two drinks a day were 37% less likely to develop dementia than teetotalers. It didn't matter whether their drink of choice was wine, beer, or hard liquor.
The reduction in risk is similar to that associated with exercising three times a week or more, Sink says.
Among people who had mild cognitive impairment at the start of the study, those who drank more than two drinks a day were nearly twice as likely to develop dementia, compared with nondrinkers.
To Drink or Not to Drink
Sink says no one should start imbibing in an effort to ward off dementia. "But older adults who are already drinking moderately don't necessarily need to cut back if they're cognitively normal," she says.
The study doesn't prove cause and effect. It could be alcohol itself or some other lifestyle factor shared by moderate drinkers that is responsible for the protective effect, Sink says.
But other research has suggested moderate drinking might protect against dementia by increasing levels of good cholesterol and preventing blood platelets from sticking together. It may also stimulate the release of acetylcholine, a chemical that's important for memory, Sink says.
So why didn't it help people with mild cognitive impairment? Sink says any benefits from alcohol may not have been strong enough to slow the degenerative disease process that's already kicked in with people who have mild cognitive impairment.
"Moderate drinking may be protective for healthy adults, but once there are memory problems, it may be very important to curtail that," says Maria Carrillo, PhD, director of medical and scientific relations at the Alzheimer's Association. She moderated a news conference to discuss the findings.