Alcohol and Alzheimer’s – How Much is Too Much?

February 22, 2023

Having one or two drinks a day may help to lower your risk of developing Alzheimer’s disease, according to a new report. But drinking more heavily could increase your risk.

The findings come from researchers who tracked nearly four million adults 40 and older living in Korea. At the start of the study, none had Alzheimer’s disease or other serious health problems, like cancer or heart disease.

Study participants completed surveys about their typical drinking habits in 2009, and again in 2011. They were grouped according to how much alcohol they typically consumed: abstainers (those who refrained from drinking), moderate drinkers (one or two drinks a day, on average), and heavy drinkers (three or more drinks a day, on average). A drink is roughly defined as 12 ounces of regular beer, 5 ounces of wine or 1.5 ounces of distilled spirits.

The researchers also recorded any changes in drinking habits over that two-year span, including whether they had increased or decreased their typical alcohol consumption.

The researchers then followed participants over the next seven years. During that time, just over 100,000 of them developed dementia, including nearly 80,000 who were given a diagnosis of Alzheimer’s disease. (Most of the others had vascular dementia, related to blood flow problems in the brain.)

The researchers found that compared to nondrinkers, those who were mild drinkers were 21 percent less likely to develop Alzheimer’s disease or another form of dementia. Moderate drinkers were 17 percent less likely to develop dementia. Surprisingly, the authors found, those who had been nondrinkers initially but who took up moderate drinking also showed a lower risk of dementia.

Heavy drinkers, on the other hand, were 8 percent more likely to develop dementia than nondrinkers. Those who reduced their drinking from a heavy to a moderate level of consumption, however, had a 12-percent decreased risk of developing Alzheimer’s disease compared to those who continued to drink heavily. The findings were published in the journal JAMA Network Open.

The study showed only a correlation between alcohol consumption and dementia and cannot prove cause and effect. Nor do they mean that those who don’t drink should take up drinking to lower their Alzheimer’s risk. The Dietary Guidelines for Americans do not recommend that anyone begin drinking or drink more for health reasons. Many earlier studies have shown that heavy drinking can also damage the brain, and even moderate alcohol consumption has been linked to certain cancers and other health problems.

Moreover, sex and body weight, along with individual differences in the ways people metabolize alcohol, affect alcohol levels throughout the body, including in the brain. So optimal amounts of alcohol are likely to vary from person to person.

Many factors affect who ultimately goes on to develop Alzheimer’s disease, and the links between alcohol consumption and brain health remain uncertain. Still, a growing body of evidence indicates that modest amounts of alcohol could have brain benefits for some.

An earlier study from Korea, for example, found that older men and women who had a habit of drinking, on average, from one to 13 alcoholic beverages a week for much of their lives had fewer brain deposits of beta-amyloid, the toxic protein that clumps together to form the telltale brain plaques of Alzheimer’s disease. Another large study of nurses found that those who consumed a drink a day or less, on average, tended to perform better on memory tests than those who abstained from alcohol entirely or drank more heavily.

Moderate drinking, such as at a cocktail party or having a glass of wine at dinner with friends, can also be a social activity, and studies show that an active social life can help to keep the brain healthy and lower the risk of Alzheimer’s disease. The traditional Mediterranean diet, which includes moderate amounts of red wine along with heart-healthy foods like fish, fruits, vegetables and whole grains, has likewise been linked to a lower risk for Alzheimer’s disease.

By  ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University. 

Source: Keun Hye Jeon, MD; Kyungdo Han, PhD; Su-Min Jeong, MD; et al: “Changes in Alcohol Consumption and Risk of Dementia in a Nationwide Cohort in South Korea.” JAMA Network Open, February 6, 2023


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