By 2050, it's estimated that 80 million Americans will be 65 years or older,1 making brain health of paramount importance. Lifestyle factors are known to be protective of or damaging to the brain, and this includes alcohol consumption.
While some research suggests wine consumption may benefit heart health and even has neuroprotective properties,2 numerous studies have shown that alcohol consumption has a detrimental effect on your brain.
Chronic excessive alcohol consumption, aka "alcohol abuse," in particular, is known to cause neuronal dysfunction and brain damage,3 but even drinking 1 gram of alcohol daily is enough to accelerate aging in your brain, according to one of the largest studies ever conducted on brain aging and alcohol.4
Daily Drinking Accelerates Structural Brain Aging
Researchers from the University of Southern California examined 17,308 human brain scans from people between 45.2 years and 80.7 years old, revealing that each additional gram of alcohol consumption per day was associated with 0.02 years, or 7.5 days, of increased relative brain age (RBA), which is a measure of a person's brain age relative to their peers, based on whole-brain anatomical measurements.
One gram of alcohol is equal to 0.035 ounces, and most people who drink alcohol are going to consume 1 ounce or more, which is equal to approximately 29 grams — an amount that would increase RBA by 0.58 years, or 211.5 days.
"Our analyses of alcohol intake frequency and RBA indicated that subjects who drank daily or almost daily had a significantly higher RBA compared to those who drank less frequently. Our finding was consistent with previous studies, which showed that heavy alcohol consumption was detrimental to the brain," the researchers wrote.5
It could be that daily, or almost daily, drinking is part of the problem, as the study did not find a significant difference in RBA among those who drank less frequently or abstained from drinking. At least one study also found that light-to-moderate alcohol intake, especially wine, was associated with larger total brain volume, suggesting it is potentially beneficial for brain aging.6
That being said, regular and extensive alcohol consumption is a known detriment to brain health, which may cause white matter and neuronal loss and a reduction of brain volume.7 This is particularly concerning, as unprecedented increases in alcohol use, high-risk drinking and alcohol use disorder (alcoholism) have occurred in recent decades.
Alcoholism May Affect 1 in 8 Americans
A study published in JAMA Psychiatry8 found that in the time period spanning 2001/2002 to 2012/2013, 30% more Americans engaged in high-risk drinking. The study included data from 79,402 Americans and found statistically significant increases in alcohol use across all sociodemographic groups.
The greatest increases occurred among heavy alcohol users; the number of people diagnosed with alcoholism increased by 49% during the study period and is estimated to affect 12.7%, or 1 in 8, Americans.9
Overall, the number of people who reported drinking alcohol (in any amount) shot up from 65% to nearly 73% of Americans. About one-third of them engage in "high-risk drinking," which was defined as five or more standard drinks for men or four or more drinks for women at least once a week. Among women, however, this type of binge drinking increased by nearly 58% over the study period.10
With heavy alcohol usage on the rise, understanding its effects on cognitive decline and neurodegenerative diseases like Alzheimer's disease will be crucial for public health.
What Does Alcohol Abuse Do to Your Brain?
A 2019 review published in Frontiers in Neuroscience addressed the complex interplay between alcohol consumption and cognitive decline, noting that chronic alcohol abuse leads to "changes in neuronal structure caused by complex neuroadaptations in the brain."11 The researchers explain:12
"In general, chronic alcohol consumption leads to degeneration of the spinal cord and the peripheral nervous system as well as malnutrition of brain cells due to changes in metabolism and lack of folate and thiamine.
Alcohol abuse also severely affects the dopaminergic system, as repeated intake of alcohol increases the tolerance and suppresses to level of excitement, so that increasingly higher doses are consumed by addicts to stimulate their reward-system."
Increasing the dose of alcohol, in turn, can lead to neuroinflammation and neural death, and chronic alcohol abuse is associated with loss of gray matter and accelerated aging-related effects. What's more, the researchers noted, "It is even possible to identify alcoholics and controls looking at MRI scans of their executive control networks and reward networks."13
Alcohol-related dementia, ARD, can also occur due to chronic, heavy alcohol consumption, leading to symptoms such as cognitive deficits and problems with professional life and social relationships. It can also lead to degeneration and demyelination of the corpus callosum in the brain, which is a hallmark of Marchiafava-Bignami disease, a progressive neurological condition associated with alcoholism.
Alcohol Increases Alzheimer's Risk, Reduces Brain Volume
Research published in the Journal of Neuroinflammation14 revealed that binge drinking or heavy alcohol consumption may make it more likely that your brain may accumulate damaging amyloid-beta proteins, contributing to the development of Alzheimer's disease.
The study focused on rat microglial cells, which are immune system cells in the brain and spinal cord that actively work to clear amyloid beta in a process known as phagocytosis. Researchers exposed the microglial cells to alcohol (in a level comparable to that found in people who drink heavily or binge drink), inflammatory cytokines or a combination of alcohol and cytokines for 24 hours.
The expression of over 300 genes was altered following exposure to alcohol, while exposure to cytokines resulted in changes in more than 3,000 genes and the combined alcohol and cytokines exposure caused changes in over 3,500 genes. Many of the altered genes were involved in phagocytosis and inflammation.15
Notably, microglial phagocytosis was also affected by alcohol, decreasing by about 15% after one hour of exposure. Although the tests were performed in isolated rat cells, which means real-life alcohol consumption in humans may lead to a different result, they suggest that alcohol may hinder the microglia's ability to clear amyloid-beta.
Alcohol abuse continues to be detrimental to the brain even in older age, as those with alcohol use disorder had brain volume reductions, which were especially pronounced in those aged 65 and older, and were seen even in those who developed alcohol use disorder in later life.16,17
Edith V. Sullivan, Ph.D., of Stanford University School of Medicine, who led the study, told the National Institute on Alcohol Abuse and Alcoholism:18
"What was particularly striking about our study was accelerated aging of brain structure that was especially prominent in the frontal cortex. Even those individuals who developed severe AUD at an older age showed accelerated loss … A take-home message of our results is that old age is not protective against developing AUD-related brain volume deficits."
Alcohol's Effect on Heart Health Influences Your Brain
There's also a complex interplay between alcohol consumption, heart health and your brain. Excessive alcohol consumption damages heart health, which in turn affects cognitive performance. On the other hand, improving heart health may improve brain plasticity and lead to enhanced neurocognitive functioning.
Therefore, heavy alcohol consumption not only may harm your brain directly but also indirectly via damages to your cardiovascular system. Researchers noted in Frontiers in Neuroscience:19
"In particular, fluid intelligence and executive functions are assumed to be enhanced and preserved the more physically active patients are and the stronger their cardiovascular system is, as people who are physically more active have a general lower risk for physical diseases.
This is related to the positive relationship of cardiorespiratory function and cognitive abilities. In accordance, decline in pulmonary function is associated with impaired memory and attention. The vitamin thiamine has been found to be a key substance in this issue, since lack of thiamine is caused by chronic alcohol abuse and leads to damages of the cardiovascular system."
Can You Buffer the Brain Damage From Alcohol Intake?
The best way to avoid alcohol-induced damage to your brain is to abstain from drinking it, especially heavily. However, nicotinamide adenine dinucleotide (NAD) (the dietary precursor of which is niacin, vitamin B3), is important if you drink heavily.
People with chronic alcoholism are at risk for niacin deficiency, both due to a reduction in dietary intake of niacin and interfering with the conversion of tryptophan to NAD.20 Small doses of NAD (not time released) can be incredibly helpful when provided while weaning off alcohol.
The treatment helps to curb cravings for alcohol, detox the body, flushes alcohol (or other drugs) out of the system and relieves withdrawal symptoms. As a potent antioxidant, NAD helps to create energy in cells' mitochondria as well as increases the synthesis of neurotransmitters in the brain.21
What's more, it's being considered as an important therapeutic strategy to help maintain optimal function in the brain and possibly even treat Alzheimer's disease.22 N-acetyl cysteine (NAC), a form of the amino acid cysteine, is another useful tool, as it's known to reduce alcohol consumption and withdrawal symptoms in rodents and cut down cravings in humans.
In a study of people who averaged one drink a week (or binge drinking 0.3 days a month), NAC increased the likelihood of alcohol abstinence and reduced drinks per week and drinking days per week.23 NAC is also beneficial for brain function, as it may decrease levels of oxidative damage by protecting mitochondrial function, and in so doing reduce Alzheimer's risk, especially when combined with lipoic acid (LA).24
Exercise Helps Reduce Alcohol Intake, Protects Brain Health
Exercise may help to mitigate some of the risks of alcohol consumption on your brain. Researchers wrote in Alcoholism: Clinical & Experimental Research:25
"Chronic alcohol abuse is related to numerous deleterious neurobiological consequences, including loss of gray matter, damage to white matter (WM), and impairment of cognitive and motor functions.
Aerobic exercise has been demonstrated to slow cognitive decline and decrease the negative neural changes resulting from normal aging and from several diseases. It is possible that exercise may also prevent or repair alcohol-related neurological damage."
Indeed, the study revealed longtime drinkers who exercise regularly have less damaged white matter in their brains compared to those who rarely or never exercise.26 The white matter is considered the "wiring" of your brain's communication system and is known to decline in quality with age and heavy alcohol consumption.
Even among chronic drinkers, those who got at least 2.5 hours a week of moderately intense exercise significantly reduced the biological impact of their drinking,27 including reducing some of the cancer and all-cause mortality risks associated with alcohol drinking.28
Exercise is also a potent tool for brain health, which is one reason it's recommended you do it regularly regardless of your alcoholic drink intake. Ultimately, however, the research is becoming clearer that in order to stay cognitively strong as you age, limiting alcohol intake is key.
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