Everyone should know this latest research
By Austin Perlmutter, MD
Depending on who you ask, you might be told to drink a few glasses of red wine a day, or to avoid alcohol altogether. The reasons for these recommendations are many, but by and large, they tend to stem from a study someone read about or saw reported on the news. So why is it so hard to know if alcohol is good or bad for us, and especially for our brains? In this article, we’ll explore the current science and some practical ideas on how to approach the topic.
What is alcohol anyway?
When people talk about drinking “alcohol,” they’re almost always referring to the consumption of ethanol. Ethanol is a natural product that is formed from the fermentation of grains, fruits and other sources of sugar. It’s found in a wide range of alcoholic beverages including beer, wine and spirits like vodka, whiskey, rum and gin. Evidence for human consumption of alcohol dates back over 10,000 years. Consumption of alcohol has and continues to serve major roles in religious and cultural ceremonies around the world. But unlike most food products, in the last century, alcohol has been wrapped up in nearly perpetual controversy over its moral effects and health implications.
How does alcohol impact the brain?
As anyone who’s consumed alcohol know, ethanol can directly influence brain function. Ethanol is classified as a “depressant” because it has a generally slowing effect on brain activity through activation of GABA pathways. In an acute sense, consumption of alcohol can lead to uninhibited behavior, sedation, lapses in judgement and impairments in motor functions. At higher levels, these effects can progress to coma and even death. There is no debate here: excessively high levels of alcohol consumption over short periods of time are toxic and potentially deadly specifically because of its effects on the brain.
The known brain-damaging effects of excess alcohol
One critical fact to understand about the overall and brain-specific effects of alcohol is that the entirety of the debate around the risk/benefit ratio concerns mild to moderate alcohol consumption. As it relates to the effects of high amounts of alcohol on the body and brain, the research is consistent: it’s a very bad choice. High amounts of alcohol use are causal risk factors in the development of disease in the heart, liver, pancreas and brain (including the brains of children in utero). In fact, 1 in 8 deaths in Americans aged 20-64 is attributable to alcohol use. When it comes to adults, excessive alcohol use can cause multiple well-defined brain issues ranging from short-term confusion to dementia.
What is “excessive” or “high” alcohol use?
Key to the nuance in the conversation about alcohol use are definitions. Across the board, “excessive” or “high” alcohol use is linked to worse overall and brain health outcomes. So what does that mean? While definitions can be variable, one way to look at this is consumption of 4 or more drinks on an occasion (for women) and 4 or more for men. Additionally, excess alcohol is defined as drinking more than 8 drinks a week (women) or 15 a week (men), or consuming alcohol if you are pregnant or younger than age 21. Beyond this, by definition, consuming enough alcohol to cause a “brownout,” “blackout,” hangover or other overt brain symptomatology is evidence that the alcohol you’ve consumed is creating problems in your brain. Alcohol use disorder (or alcoholism) is also a clear issue for the brain. It has been linked to higher risk for dementia, especially early-onset dementia in a study of 262,000 adults, as well as to smaller brain size.
Is there a “safe” amount of alcohol for the brain?
In a highly publicized article from Nature Communications, researchers looked at brain imaging data from nearly 37,000 middle-aged to older adults and compared the scans to reported alcohol consumption. The findings were profound: more alcohol intake correlated with a smaller brain, even in people only drinking one or two alcoholic beverages a day.
Conversely, other recent data suggest a lower risk for dementia in people consuming a few alcoholic beverages a day. This includes a 2022 study showing that in around 27,000 people, consuming up to 40 grams of alcohol (around 2.5 drinks) a day was linked to lower risk for dementia versus abstinence in adults over age 60. A much larger study of almost 4 million people in Korea noted that mild to moderate alcohol consumption was linked to lower risk for dementia compared to non-drinking.
How do we make sense of this data?
When it comes to the bottom line as it relates to alcohol consumption and brain health, the data are rather solid on some fronts, and a bit less so on others. There’s also the potential for confounding variables, including the fact that many people like to drink alcohol to enjoy and enhance social bonds (which we know are beneficial for the brain). Here’s a summary of what the most recent research is telling us:
Heavy or excessive alcohol consumption is dangerous to the brain for a number of reasons.
Alcohol use disorder (alcoholism) is a risk factor for developing dementia.
Experiencing transient memory loss, “blackouts” or hangovers related to alcohol consumption are overt evidence for threats to brain health.
The impact of mild to moderate alcohol consumption (1-3 drinks a day) on brain function are less clear, but it seems unreasonable to start alcohol use for brain health.