According to a recent study published in The Lancet , light-to-moderate consumption of alcohol (1-3 drinks per day), may reduce your risk of developing dementia of any kind, including Alzheimer's disease.

About the study

Dutch researchers studied 5395 men and women who were already participating in the Rotterdam Study, a larger study of people aged 55 and older in a suburb of Rotterdam, The Netherlands. For this recent study, the researchers included only Rotterdam participants who were free of dementia and had completed a food frequency questionnaire (including alcohol intake) between 1990 and 1993. This study did not include Rotterdam participants with low cognitive function or those living in nursing homes.

At the start of the study, a trained interviewer used a food frequency questionnaire to collect information about participants' intake of food, alcohol and other beverages. Other information collected included age, sex, diabetes status, blood pressure, education level, smoking status, body mass index, medication use, history of stroke or heart attack, and apolipoprotein E gene information (a known risk factor for Alzheimer's disease and cardiovascular disease).

All information was collected again during follow-up interviews in 1993-94 and between 1997 and 1999 (the year the study ended). At the start of the study and at both follow-up interviews, participants were also given cognition tests; if the results indicated possible dementia, they were confirmed via neurological exam, neuropsychological testing for dementia, and MRI (if possible). Additionally, the researchers tracked the participants through a study database that was linked to participant medical records with their regular doctors.

In 1999, after an average of six years of follow-up for each participant, the researchers compared the daily alcohol intake of each participant with their cognitive status.

The findings

People who consumed one to three alcoholic drinks per day were 42% less likely to develop any form of dementia than people who did not drink alcohol at all. More specifically, consuming one to three alcoholic drinks per day reduced a person's risk of vascular dementia by 70%. Consuming four or more alcoholic drinks per day did not reduce the risk of dementia.

In calculating these statistics, the researchers factored in common risk factors for dementia. Of note, all types of alcohol - beer, wine, liquor, fortified wine (i.e., sherry, port)- produced a similar reduction in risk.

There are limitations to this study that are worth noting. First, measurements of alcohol intake were based on information reported by the participants and could not be confirmed with any laboratory tests. This may have compromised the accuracy of the information because it is difficult to assess lifetime alcohol intake habits based on their recall of many years. Second, although the researchers collected information on the number of glasses of alcohol consumed per day, there was no information as to the amount of alcohol consumed in each glass. Finally, the follow-up period of six years is fairly short, meaning that some participants may yet develop dementia.

How does this affect you?

Studies have shown that light-to-moderate alcohol intake is associated with better cardiovascular health. Because there is evidence that vascular factors may be involved in the cause of dementia, the study authors suggest that alcohol's affects on vascular health may be responsible for the apparent protective effect of alcohol. They also suggest that light-to-moderate amounts of alcohol may stimulate production of acetylcholine (a substance known to facilitate memory and learning) in the brain.

Is this an invitation to drink up? Not without some caveats. While alcohol does appear to play a role in heart health - and now in the onset of dementia - steady alcohol consumption can cause liver disease, complicate other medical conditions, and may increase the risk of some kinds of cancer. In addition, a steady intake of alcohol can trigger an unhealthy rise in blood triglyceride levels, a potential risk factor for heart disease.

For people who already enjoy alcohol, a reasonable limit is about two drinks per day for men and one for women (despite the fact that some of the drinkers in this study were consuming more than that). A drink is calculated as 12 oz of beer, 5 oz of wine, or 1.5 oz of distilled spirits. If you don't drink alcohol but are curious as to whether you should, talk to your health care provider to weigh the benefits of moderate alcohol intake and decide if alcohol should be part of your daily routine.