After a Danish study published July 28 found that moderate alcohol consumption could potentially reduce the risk of diabetes, researchers in the US now suggest that a few alcoholic drinks per week could help prevent cognitive impairment and dementia in old age.
Researchers at the University of California's San Diego School of Medicine in the US studied the drinking habits of 1,344 older, white, middle-to-upper-middle-class adults in the US for 29 years, from 1984 to 2013, to evaluate the impact of alcohol consumption on the brain when participants reached their eighties.
"It is important to point out that there were very few individuals in our study who drank to excess, so our study does not show how excessive or binge-type drinking may affect longevity and cognitive health in aging," said senior author Linda McEvoy. In fact, long-term excessive alcohol intake is known to cause alcohol-related dementia.
The study defines moderate drinking as drinking up to one alcoholic drink a day for adult women of any age and men aged 65 and older, and up to two drinks a day for men aged under 65.
Heavy drinking is defined as up to three alcoholic drinks per day for adult women and men over 65, or four drinks a day for men under 65.
After assessing participants' cognitive health every four years, the researchers observed that men and women aged 85 and older who had consumed "moderate to heavy" amounts of alcohol -- one to three glasses per day for women and men over 65, or four drinks a day for men under 65 -- five to seven days a week, were twice as likely to be cognitively healthy than non-drinkers.
As for the frequency of consumption, after taking into account medical and lifestyle factors, the researchers found that those who drank a small amount of alcohol almost daily were more likely than non-drinkers to live to the age of 85 without cognitive impairments or dementia.
The researchers point out that their study does not suggest that drinking is responsible for increased longevity or cognitive health. It should be noted that alcohol consumption, particularly of wine, is associated with higher incomes and education levels, which in turn are associated with lower rates of smoking, lower rates of mental illness and better access to health care.
The study is published in the Journal of Alzheimer's Disease.