Can Even Moderate Drinking Cause Brain Damage?

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Research reported last week discovered even moderate drinking could damage the brain. Considering 78% of Australians over 14 years old drink alcohol, this is understandably concerning information.

News reports were reasonably accurate in their interpretation of the study. With measured headlines use words such as may damage the brain and linked with, these reported that the observational survey procured an association between moderate booze and brain damage , not a causation.

The Financial Review ran the headline 😛 TAGEND

“The silent injury from drinking moderately down the decades”

and CBS News said 😛 TAGEND

“Even moderate booze could harm the brain.”

Others, such as the Deccan Chronicle, were more hyperbolic, hinting at causation 😛 TAGEND

“Moderate booze leads to severe brain damage.”

We know about 17% of Australians booze at levels considered to threw them at risk of long-term damage such as diabetes, liver disease and cognitive problems.

And its well established heavy booze over ten years or more can cause significant cognitive difficulties. These include disorders such as Korsakoffs Syndrome and Wernickes Encephalopathy, where memory and other essential reasoning functions, as well as engine coordination, are severely and permanently damaged.

But what about those of us who have two to three boozes a nighttime?

First, this is an observational learn that followed people over time, demonstrating an association between their alcohol intake and certain cognitive roles. Observational analyses cannot prove that one( alcohol) made the other( impaired brain function ).

And while booze can potentially affect multiple parts of the brain, the researchers discovered significant impact in only one part of the brain. And that does not seem to correlate with poorer brain functioning overall.

The Conversation, CC BY-ND

How was such studies conducted ?

The BMJ

Participants were categorised into four groups based on how much alcohol they drank per week. The abstinent group drank less than one standard beverage a few weeks, and the sun between one and seven drinks. Moderate drinkers had between seven and 14 sips a week for women, and between seven and 21 guzzles for men. Men who had 21 or more drinkings per week, and women who drank 14 or more, were classified as unsafe drinkers.

The participants had brain scans once( at the 30 -year point) and neuropsychological testing five times over the 30 years.

What did it find ?

The main difference between the drinking groups was a smaller hippocampus the area of the brain important for learning, recollection and spatial awareness in people who drank more.

Compared to abstainers, people who drank an average 30 or more guzzles a week over the 30 years were more likely to have a smaller hippocampus. But even those drinking between 14 and 21 drinks a week had, on average, a smaller hippocampus.

The Conversation, CC BY-ND

How should we interpret research results ?

There are a few reasons to be cautious about these results. The examine looked at brain function( how well the brain projects, measured by neuropsychological tests) over day. But researchers measured brain structure( the physical make-up of the brain) with a brain scan only at the end of the study.

Although the hippocampus was smaller in the heavier booze groups, booze consumption did not seem to affect the duties of the brain. There was no alcohol-related decline in measures of remembrance and executive functions( such as planning, problem solving and impulse control ). These are typically the cognitive domains most sensitive to effects of booze and most likely to show the negative impact of hippocampal shrinkage.

Not having scanned the brains of participants at the beginning of the study means researchers did not know the original size of their hippocampi. They visually assessed the size of brains from the scans and compared them to expected brain size, using an established scale for that intent. Around 65% of people who boozed 14 to 21 guzzles a week showed a smaller hippocampus, but even 35% of the abstainers had hippocampal atrophy.

The study utilized many measures of brain functioning( visual and verbal memory, executive function and working memory ), but it procured alcohol-related decline in only one function verbal fluency( the ease with which we can retrieve terms ). And none of the groups were particularly impaired overall is comparable to people in the general population of the same age and education level.

Researchers scanned participates brains only once, at the end of the study. from shutterstock.com

What else should we take into account ?

In a study with a moderate number of people like this, it can be harder to assess brain differences because it is difficult to properly take into account other important factors such as age, gender, mental health problems and other drug use.

It seems logical that something like booze, which has a strong short-term impact on the brain, might have longer-term results, and this study adds to the growing proof that alcohol can impact brain structure. But we are still some way off knowing how much moderate alcohol intake affects the brain and whether that translates to a functional impairment.

Alcohol is implicated in a number of physical and mental health problems and should be used occasionally and within recommended restrictions. Studies that have reported health benefits of moderate booze in the past have now been shown to be methodologically flawed.

The Australian National Health and Medical Research Council guidelines on booze intake recommend that adults( both men and women) should drink a maximum of two standard drinkings a period to preserve long-term health and no more than four guzzles on one occasion to prevent short-term damage. Nicole Lee and Rob Hester

Peer Review

I agree with comments and observations constructed in this Research Check. There are several other factors to consider when interpreting this study.

Firstly, health researchers observed a decline in verbal fluency, as well as atrophy of the hippocampus in participants. But( as Figure 7 in the study shows) there is no pathway between hippocampal volume and verbal fluency deterioration. Verbal fluency is usually associated with a zone of the brain “ve called the” frontal lobe, while the hippocampus is associated with memory.

And apart from differences in verbal fluency, the researchers detected no other differences between groups on exams associated with the hippocampus, such as those for learning and recollection. In the absence of changes to other executive and recollection tests, it is uncertain what the clinical and functional meaning of a decrease in verbal fluency means.

Further, its unknown how the participants spaced out their booze intake. There is new indication demonstrating moderate drinking in a binge fashion is very dangerous to cognitive ability. The researchers did not distinguish between those who drink two standard sips per period throughout the week and the individuals who saved their 14 guzzles for a single session on the weekend. This could also be mediating their results.

There is also evidence that abstinence from alcohol can improve brain structure and cognitive performance, even after a few months. So dont be too alarmed when reading these results. Travis Wearne


The Conversation This article has been amended to say that the NHMRC guidelines recommend adults drink no more than four beverages on one occasion .

Nicole Lee, Professor at the National Drug Research Institute, Curtin University and Rob Hester, Professor, Melbourne School of Psychological Sciences, University of Melbourne

This article was originally published on The Conversation. Read the original article.

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