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Alcohol – good for your heart, bad for your brain?

Recent reports from CNN suggest that alcohol is good for your heart when consumed in moderation. Moderation by their definition is 1 drink per day for women and 1-2 drinks per day for men. While this message has been touted for years and widely accepted in both the research world and general public there are some important questions that need to be asked.

How does alcohol intake influence the brain? Dr. Amen suggests that any alcohol intake leads to reduced brain volume. On one of his blog posts Dr. Amen refers to other literature that back up his findings regarding brain volume. Dr. Amen is a well-known neuroscientist and psychiatrist who teaches at the University of California. The major downfall of Dr. Amen is that he has very few peer-reviewed publications. In the science world, this is a major red flag. The number of publications a scientist has is typically viewed (by other scientists) as an indication of their credibility and ability. However, the number of journals that make it through peer-review that are absolute garbage in terms of study design is staggering. Thus, just because Dr. Amen doesn’t have a large number of publications does not necessarily mean his research is not credible, it just means that the reader or listener should be a little more wary.

Dr. Amen has demonstrated the relationship between brain volume and alcohol intake using single photon emission computed tomography (SPECT). This tool allows him to get an idea of how the brain is functioning. If a patient comes in complaining of exhaustion, instead of prescribing medication to treat the exhaustion (which is commonly associated with depression) he looks at the brain to see the root cause. It may in fact be due to mental health issues or perhaps the chronic use of various substances (nicotine, caffeine, alcohol, cannabis). Check this link out to see the actual SPECT brain images (I highly recommend viewing these images).

The images are fairly scary. Yet these images represent brains that have suffered chronic abuse typically from individuals that over-indulge (I am currently searching for SPECT images of moderate users). What about moderate users? In my search for articles, I found a bundle of peer-reviewed articles looking at the effects of chronic alcohol use on brain volume and very few on moderate use. Of the limited few, there is evidence to suggest (albeit not statistically significant) that moderate alcohol users (30 – 80 grams of alcohol per day i.e. 3-6 drinks per day) have increased ventricle size and space between the brain and the cranium. What does that mean? That their brains are smaller.

One study looked at the afects of alcohol during neuronal development in rats. Rats were given either 6.6 g/kg or 3.3. g/kg of alcohol on postnatal day 4. On postnatal day 10 their brain volume was assessed. The higher dose of alcohol significantly restricted wholebrain, forebrain, cerebellum, and brain stem weights. This isn’t anything new in the world of science, fetal alcohol syndrome has been known about for years. However, this reiterates the negative consequence of alcohol consumption on the brain.  

So it would seem that moderate alcohol consumption affects the brain. Yet, the definition of moderate differs by study. In the study I mention moderate is defined as 3-6 drinks per day. The article that discusses heart health and alcohol consumption defines moderate as 1-2 drinks per day. There is an obvious difference making a comparison difficult. 

The heart and brain are not the only organs affected by alcohol. You have to consider the liver, your kidneys, your intestines. You also have to consider how alcohol will affect blood volume and thus, blood pressure. And what about mood? Alcohol has a large influence over one’s mood which will in turn, lead to changes in behaviour.

So while the CNN article suggest that alcohol is good for the heart (in moderation) you always need to consider the other side of the coin. My recommendation – don’t accept everything at face value. While a media story may be appealing, it is always important to do your research and come up with your own opinion.

M

References:

Eckardt M, et al. 1998. Effects of moderate alcohol consumption on the central nervous system. Alcoholism: Clinical and Experimental Research 22(5):998-1040

Goodlett C, et al. 1990. A single day of alcohol exposure during brain growth spurt induces brain weight restriction and cerebellar Purkinje cell loss. Alcohol 7(2):107-114.

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