How does alcohol consumption affect your brain?
Does it have a preventative effect against cognitive decline or does it cause cognitive decline?
Levels of Consumption and Their Impact
Recent research found that moderate drinking is associated with negative impacts on the biology of the brain including the reduction in the size of the hippocampus. Consuming alcohol was also associated with faster cognitive decline in the area of verbal fluency.
The study found these effects with moderate drinking — drinking that was within levels considered safe. This research should make us all examine our drinking habits because of the long-term implications for brain health.
Recently the chief medical officer in the United Kingdom reduced the amount of alcohol consumption that was considered safe from 21 units per week to 14 units per week. Units of alcohol are used to track consumption because size and strength of drinks varies. Calculating the amount of alcohol being consumed based on units is a more accurate way of monitoring alcohol intake.
So how much is a unit? In standard offerings of wine, beer, and whiskey the units are:
- 76 ml of standard 13% wine
- 250 ml of standard 4% beer
- 25ml of standard 40% whiskey
You should note that alcohol content in wine and beer can vary, so this guideline is based on standard percentages. Obviously if the alcohol content is higher, the amount to make a unit is lower. As well, while a spirit drink is diluted with a mix, wine and beer is typically poured into a glass. So, taking a beverage with a standard alcohol content, the unit recommendations translate into six 175ml glasses of wine per week or six 598 ml pints of beer.
Who Did They Study?
The study examined the Whitehall II cohort. The Whitehall II cohort is a group of 10,000 nonindustrial civil servants that have been studied for 30 years. The study was examining socioeconomic status, stress and cardiovascular health.
In this current study, a group of 550 people were randomly selected for a sub-study on alcohol consumption. Their alcohol consumption rates were compared with their brain imaging MRIs to determine the effect of alcohol consumption on brain structure.
The researchers found that individuals who drank more than 30 units of alcohol a week had higher odds of hippocampal atrophy than those who did not drink. So that translates into more than 12 pints of beer a week or two or more pints of beer a day.
When broken down in to a daily intake, it is fairly easy to image consuming two beers or two glasses of wine a day. And if you are a generous pourer, you may only need to consume one glass of wine to hit these levels.
The Impact of Alcohol Consumption on the Brain
Structural change caused by alcohol should be a concern. The hippocampus is an important part of the brain associated with memory. A shrinking hippocampus is going to affect brain function. It should be noted that a shrinkage in this area of the brain is also found in individuals with Alzheimer’s disease.
While the risk for structural changes to the brain was higher for individuals who consumed more than 30 units of alcohol a week it was also elevated in those who were considered moderate drinkers. So even if you were considered a moderate drinker, the study found structural changes to the brain in areas associated with memory and executive functioning. In fact, those individuals who were moderate drinkers (14 to 21 units per week) had a three times higher risk of hippocampal atrophy.
These findings compelled the UK Chief Medical Officer to reduce the recommended rates of alcohol consumption to 14 units and below.
The authors of this study hope that it highlights the adverse effects of even moderate levels of alcohol consumption on brain structure, memory, and executive functioning in the brain over time.
This study is worth thinking about when we consider our own alcohol consumption and the effects it will have over our lifetime. The clinicians involved in this study are changing their practice guidelines and will tell their patients that drinking over 14 units weekly may not be safe for their brain health.
While we learn more and more about the impact that lifestyle choices have on brain health and dementia risk, it is worth looking at our alcohol consumption habits. They may need adjusting.