A Drink a Day May Keep Alzheimer's Away (Analysis of 143 studies shows risk decreased by 23%)

Medscape Medical News ^ | August 26, 2011 | Fran Lowry

[Stoat]

A Drink a Day May Keep Alzheimer's Away

Fran Lowry

 

August 26, 2011 — Light to moderate drinking seems to reduce the risk for dementia and cognitive decline, according to a new study published in the August issue of Neuropsychiatric Disease and Treatment.

A meta-analysis of 143 studies on the effects of alcohol on the brain showed that moderate drinking, defined as no more than 2 drinks a day for a man and no more than 1 drink a day for a woman, reduced the risk for Alzheimer's disease and other forms of dementia by 23%.

"It doesn't seem to matter if it's beer, wine, or spirits, as long as the drinking was moderate," Edward J. Neafsey, PhD, from the Department of Molecular Pharmacology and Therapeutics at Loyola University Medical Center, Maywood, Illinois, told Medscape Medical News.

Dr. Edward J. Neafsey

Dr. Neafsey and coauthor Michael A. Collins, PhD, became interested in seeing whether alcohol might be protective of human brains after their experiments showed that rat brains exposed to low doses of alcohol for a few days demonstrated resiliency when subsequently treated with a toxin.

"If the rat brain slices were treated for 5 or 6 days with low alcohol and then the toxin was administered, there was hardly any damage, whereas if they didn't get the pretreatment with alcohol, there was significant damage. This led us to ask if there was anything in the human literature that would fit with this protective effect of alcohol," Dr. Neafsey explained.

The researchers reviewed studies dating from 1977 up to the present. The studies fell into 2 categories: those that provided ratios of risk between drinkers and nondrinkers (n = 74) and those that rated cognition in drinkers as "better," "no different," or "worse" than cognition in nondrinkers (n = 69).

Heavy Drinking a Different Story

Light to moderate drinking conferred a similar benefit, but heavy drinking (more than 3 - 5 drinks/day) was associated with a nonsignificantly higher risk for dementia and cognitive impairment.

Most of the studies did not distinguish between the different types of alcohol, but in a few studies, wine appeared to be more beneficial than beer or spirits. "It really seemed to be that alcohol per se was protective, not the type, because the few studies that did make the distinction reported no difference among the effects of the different types of alcohol," Dr. Neafsey said.

The protective effect of moderate drinking held after adjusting for age, education, sex, and smoking.

A number of explanations for the protective effect of moderate alcohol have been proposed. Some dementias are related to cardiovascular system problems, such as atherosclerosis, and alcohol may be protective because it raises the level of high-density lipoprotein (the good) cholesterol and might improve blood flow in the brain.

One theory that Dr. Neafsey and Dr. Collins are working on now holds that alcohol acts as a mild stressor for brain cells and "preconditions" them, making them better able to ward off stress.

"Alcohol doesn't kill the brain cells, but it's a slight stress. When the cells are exposed they increase levels of various protective compounds, so...they are prepared when something more stressful that might kill or damage them comes along. The theory is called 'preconditioning,' where a mild stress given a few days before a severe stress causes a significant protection."

Understanding the mechanism of alcohol's protective effect could lead to a treatment to prevent cognitive impairment and dementias, Dr. Neafsey said.

"Whether it's treatment with a pill or a lifestyle change, if we could understand the mechanism, it would improve our ability to deal with these illnesses," he said.

Novel Approach

Medscape Medical News asked Anton P. Porsteinsson, MD, the William B. and Sheila Konar professor of psychiatry at the University of Rochester School of Medicine, New York, to comment on this study.

"This is a well-done meta analysis. The findings are consistent with other meta analyses that have been done. Am I tremendously surprised at the findings? No, because they are looking at the same pool of studies," Dr. Porsteinsson said.

"The fact that they approach it in slightly different ways and yet find similar outcomes makes me confident that this is what the data are actually signaling to us: that very modest alcohol consumption is protective," he said.

The next step is to figure out how moderate alcohol consumption exerts its protective effect.

"Is it some direct effect of the alcohol on the brain? Are people who consume moderate amounts of alcohol different in some way, in their diet, or their level of exercise? Are low concentrations of alcohol neuroprotective? Is it through some metabolic impact?" Dr. Porsteinsson said.

Also interesting was that alcohol appeared to protect against all types of dementia, he said.

"This makes it less likely to have a direct effect on beta amyloid or tau, but more of a global effect. It is an interesting review. They made it a pleasure to read."

The study was supported by the National Institutes of Health. Dr. Neafsey, Dr. Collins, and Dr. Porsteinsson have disclosed no relevant financial relationships.

Neuropsychiatric Dis Treat. 2011;7:465-484. Abstract

[meyer]

Oops - I think that the conversion chart (grams to ounces) is dealing with weight ounces, not the liquid measure of ounces. As in, 16 ounces to the pound, rather than 8 ounces to the cup.

[Stoat]

You'll frequently find liquid measures expressed in grams instead of ounces in medical parlance.

How does that reconcile with liquids of different densities? 

 

Prescriptions involving liquids can be expressed in a variety of ways, but since in a given instance you're going to be referring to a single substance, it's just a matter of mathematical conversion from one mode of expression to another. 

[Stoat]

Oops - I think that the conversion chart (grams to ounces) is dealing with weight ounces, not the liquid measure of ounces. As in, 16 ounces to the pound, rather than 8 ounces to the cup.

 

Yes, you're right! My bad...I missed lunch today ;-)

Here's a fluid ounces to grams calculator:

 

Convert US fluid ounce to gram - Conversion of Measurement Units

 

It makes a difference....dry ounce conversion is shown in the chart as 8 ounces equalling approx. 226.8 grams whereas the fluid ounces calculator gives us 236.5882375 grams for eight fluid ounces.

Thanks for catching my error :-)

[meyer]

You also have to consider the density of the liquid in question. For example, a liquid ounce of water weighs considerably less than a liquid ounce of, say, mercury. Most oils are a bit less dense than water and therefore weigh less per unit volume than water, while other liquids like nitric acid and vinigar weigh more than water for the same volume measurement.

[Stoat]

Yes, all very true. When dealing with different substances you’ve got to consider that in order to be accurate.

[meyer]

When dealing with different substances you’ve got to consider that in order to be accurate.

True. Sorry I missed your earlier reply - yes, if you're dealing with the same substance over and over, it's a simple ratio (g/cm3, lb/gal, etc.). So many threads, so little time.

[Stoat]

No worries! :-)  Here's a stylish adult beverage for you :-)

 

 

Cheers!  :-)

[meyer]

MMMmmmm....

In my mind, that’s Glenlivet on the rocks.

[Gene Eric]

Arguably good for the heart too.

Caffeine and continual learning have also been reported to mitigate the onset of Alzheimer’s.

[Taffini]

thanks, I’m hoping brandy taste better than wine...

[Taffini]

thanks Stoat

[jdsteel]

You can always try a decent vodka mixed with juice or tonic. Iced tea and lemonade (or both mixed together) might do the trick. One shot of hard liquor is considered a “drink”, so in a tall glass it can be only a slight difference in taste.

[Silentgypsy]

If you put some honey dew melon in a blender and add a splash of creme de menthe (sp?), it tastes very nice. How much creme de menthe constitutes one drink, I wonder. (Had a huge melon-patch bounty one year—everyone enjoyed this slushy mixture!)

[Steve Van Doorn]

By using Grams rather then liquid measurements you have to keep track of every substance your working with. It sounds unorthodox why would they do this?

[Doe Eyes]

You'll frequently find liquid measures expressed in grams instead of ounces in medical parlance.

The metric system was created for the One World Government.

Liberia, Myanmar and the United States are holding out.

[neverdem]

Thanks Stoat for the twofer, the metanalysis linked to its abstract! You’re a gentleman or a lady plus a scholar.

Thanks Stoat and decimon for the pings.

[Stoat]

thanks, I’m hoping brandy taste better than wine...

You're quite welcome, and if you don't care for any of the brandy cocktails or the excellent suggestions from jdsteel and Silentgypsy, you can try whisky, vodka, sherry, schnapps, rum, scotch, beer, and probably quite a few other options that I can't think of because I don't drink so much!  ;-)  The important thing to remember is this sentence from the article:

"It doesn't seem to matter if it's beer, wine, or spirits, as long as the drinking was moderate," Edward J. Neafsey, PhD, from the Department of Molecular Pharmacology and Therapeutics at Loyola University Medical Center, Maywood, Illinois, told Medscape Medical News.

if you're interested in finding something that you can enjoy, one option is going to a quality cocktail bar that has a knowledgeable bartender.  There, you can try different things without having to buy a whole bottle for each experiment :-)

A good bartender will also be able to make good recommendations for you based upon what you indicate that you already like.

Good luck :-)

[Stoat]

How much creme de menthe constitutes one drink, I wonder.

CDC - Frequently Asked Questions - Alcohol

What is a standard drink in the United States?
A standard drink is equal to 13.7 grams (0.6 ounces) of pure alcohol. Generally, this amount of pure alcohol is found in

• 12-ounces of beer.
• 8-ounces of malt liquor.
• 5-ounces of wine.
• 1.5-ounces or a “shot” of 80-proof distilled spirits or liquor (e.g., gin, rum, vodka, or whiskey).

[Stoat]

By using Grams rather then liquid measurements you have to keep track of every substance your working with. It sounds unorthodox why would they do this?

Speaking in terms of  how this relates to medicine, the recommended dosages of all medications are going to be determined on a case by case basis, meaning the dosage is specifically determined for each medication.  Since you're only dealing with one medication at a time, each one has a dosage and an administration protocol associated with it, so it's actually quite straightforward.

Since you're usually dealing with extremely small quantities of a given drug, the metric system is preferable because it allows far greater precision when dealing with these tiny quantities.  I'd rather have a medication expressed as ".05mg" than "1/516 oz".  Far easier to deal with when dosage changes are called for as well.  Frequently it's a merely a matter of moving the decimal and not much more.

[Stoat]

Thanks Stoat for the twofer, the metanalysis linked to its abstract!

You're quite welcome & I'm delighted that you've found it to be helpful.  I always try to link to original source material whenever I post at FR, and I'm happy you found it useful :-)

You’re a gentleman or a lady plus a scholar.

I'm a proud, unapologetically-male stoat, and I thank you for your gracious compliments :-)