“A glass of wine a day keeps the doctor away.” This is a quote most of us have heard, with some using it to justify daily alcohol consumption. Now, you may be asking, “It’s just one glass, how harmful could it be?” According to research, moderate alcohol consumption can lead to adverse effects, specifically on your brain.
The “Safe” Daily Amount
The Centers for Disease Control and Prevention’s guidelines for alcohol consumption state that women may have one drink or less a day, and men may have two drinks or fewer a day. As the most socially acceptable drug in the world, it was measured that over 2021-2022, 63% of U.S. adults aged 18 and older consumed alcohol.
The research speaking against heavy drinking and its effect on the brain is clear. Heavy alcohol consumption has been linked to brain shrinkage and cognitive impairment. For this reason, many have cut their alcohol consumption, in the belief that it is healthier. However, according to studies, even the slightest consumption of alcohol carries a risk to the brain.
Brain Shrinkage
In a study by the University of Pennsylvania, researchers aimed to analyze the effect of low alcohol consumption on the brain. The study included over 36,000 middle-aged adults in the United Kingdom. The participants provided detailed medical and genetic information and also underwent MRI scans of their brains.
Henry Kranzler, who directs the Penn Center for Studies of Addiction, says, “… although (the) National Institute on Alcohol Abuse and Alcoholism recommends that women consume an average of no more than one drink per day, the recommended limits for men are twice that, an amount that exceeds the consumption level associated in the study with decreased brain volume.”
The Impacts of Decreased Brain Volume
The study found that light to moderate drinking (as little as a glass of beer or wine daily) is associated with reduced brain size and structure. James Giardano, Ph.D., a professor of neurology and biochemistry at Georgetown University Medical Center in Washington, D.C., shares that alcohol use reduces brain volume by causing brain cells and cells in their connective tissue to expel water. While your brain naturally shrinks as you age, alcohol intake can accelerate this decline in size. This also leads to a faster decline in memory, decision-making, and other brain functions.
The parts of the brain most vulnerable to this are white matter and dendrites.
Brain Matter
The study found that alcohol consumption was related to white matter microstructural alterations in several white matter tract regions connecting large-scale networks and deeper white matter systems. These adverse effects, which are also seen in gray matter, are clear to see in individuals who are consuming an average of only one to two alcohol units per day.
Affected Sections Of The Brain
Grey Matter: This is a tissue found in your brain and central nervous system via the spinal cord. Playing a critical role in everyday functioning, it makes up about 40% of your brain.
Shannon Hallaway, Ph.D., says that “more grey matter is associated with better cognitive function.”
When we experience a decrease in brain gray matter, which is recorded in the mentioned study. This leads to a wide range of issues, including:
- Cognitive impairment
- Issues with reasoning and judgement
- Motor function issues
- Difficulty forming and retaining memories
- Inability to control emotions
White Matter: Found in the deeper tissues of the brain, white matter makes up about 60% of it. In a healthy brain, white matter provides essential connectivity. It is responsible for connecting different brain regions to networks that perform various mental operations. Its main role is to allow the transmission of information between the different areas of gray matter within the central nervous system. Unlike gray matter, which peaks during childhood development, white matter keeps developing until your late 20s.
Effects of a decrease in white matter include:
- Cognitive impairment
- Cerebrovascular accidents
- Mood disorders
- Balance dysfunction
Increased Iron Accumulation
Looking at almost 21,000 participants in the UK Biobank, another study linked alcohol consumption above 7 units (56g)/four standard drinks per week, each week with markers of greater iron accumulation in the basal ganglia. This is a group of structures deep within the white matter of the brain, responsible for performing various cognitive, emotional, and movement-related functions.
Heavy alcohol consumption has been associated with iron accumulation in the brain. For a long time, the ability of moderate alcohol consumption to cause this has been unknown. To investigate the possible link between moderate alcohol consumption and iron levels, a study was conducted and published in Plos Medicine.
According to lead researcher Dr. Anya Topiwala, Ph.D., “This study represents the largest investigation of moderate alcohol consumption and brain iron accumulation to date.” She further went on to state that the “results indicate that greater brain iron levels could be a potential mechanism for alcohol-related cognitive decline.”
The effects of brain iron accumulation include:
- Dementia
- Difficulty speaking and swallowing
- Muscle problems such as rigidity or involuntary muscle contractions (dystonia)
- Seizures
- Tremors
- Vision loss
- Weakness
Henry Kranzler, who wasn’t involved in this study, says “the analysis suggests that dangers in iron accumulation may contribute to the adverse effects on the brain structure and cognitive performance seen in people who consume alcohol in (moderation).” He does add that “the findings, though, are largely limited to the basal ganglia“.
This has raised concerns about the limitations of both studies.
Study Limitations
In terms of the first study by the University of Pennsylvania, Emmanuela Garkidou, alcohol researcher and professor of health metrics sciences at the University of Washington, says: “It seems that they only have information on how much people drank the year prior to when the images were taken.” She adds that it is important that cumulative consumption of alcohol be included in the study of its long-term effects on the brain.
This is vital because the study subjects could have had a higher or lower alcohol intake before the study, thereby influencing the final results. The researchers, too, agreed that the study has limitations. However, Kranzler states that the large group of people included helped provide “a clearer picture” of alcohol’s effect on brain volume.
Varying Research
Research has produced conflicting results on alcohol and its brain effect. Sure, research has linked heavy drinking to negative brain changes, but the results begin to vary with moderate consumption.
Some studies suggest that moderate consumption doesn’t have any effect on the brain, with others suggesting that light to moderate drinking may be beneficial for older adults. However, Kranzler states that “the idea that moderate drinking promotes health appears no longer defensible.”
The Bottom Line
While most people believe that having a glass of wine a day can boost your overall health (from boosting heart health to reducing your risk for some cancers), this research should probably make us reevaluate our lifestyle choices. Kanzler adds that as a lover of good wine, “the findings have led me to rethink (how much I drink).”
The bottom line is that alcohol is not good for your brain. So the next time you think of ordering that glass of rose, think of the implications it could have on your brain’s health. Ensure that you consult your doctor to establish how it may be affecting you, and what adjustments you need to make to ensure that your brain isn’t left suffering.
