WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
Excess alcohol consumption is known to harm brain health. In the case of binge drinking or heavy alcohol consumption, it may even make it more likely that your brain may accumulate damaging beta-amyloid proteins, potentially contributing to the development of Alzheimer's disease.1
However, controversy remains over whether all alcohol consumption is harmful, with some research suggesting that moderate intake may instead have a protective effect.
Preclinical studies from both animal and cell culture models have shown that consuming moderate amounts of alcohol may be protective against Alzheimer's by attenuating beta-amyloid production, but little is known about how this affects beta-amyloid deposition in the human brain — leading researchers to conduct a study to find out.2
Moderate Drinkers Had Less Beta-Amyloid in the Brain
Researchers from Seoul National University College of Medicine conducted a study involving 414 middle- and old-aged individuals who were free from dementia and did not have an alcohol-related disorder. The participants were interviewed about their current and past alcohol intake and had brain imaging to check for Alzheimer's disease pathologies.
Moderate drinking was defined as one to 13 standard drinks a week, with a standard drink defined as 12 ounces of beer, 5 ounces of wine or 1.5 ounces of hard liquor. Those who drank moderately over the course of decades indeed saw benefits, with a 66% lower rate of beta-amyloid deposits in their brains compared to nondrinkers.3
Those who recently started drinking moderately did not have the same results, however, nor did those who drank more than 13 standard drinks a week. According to the study:4
"We observed that moderate lifetime alcohol intake (i.e., 1–13 standard drinks [SDs]/week) was significantly associated with lower amyloid deposition compared to no drinking, whereas current alcohol intake did not affect amyloid deposition.
The present findings from middle- and old-aged individuals with neither dementia nor alcohol-related disorders suggest that moderate lifetime alcohol intake may have a beneficial influence on AD by reducing pathological amyloid deposition."
Because the study relied on participants' recall for alcohol drinking history and was observational in nature, it does not prove that alcohol consumption caused the reduction in beta-amyloid. However, the study's senior author, Dong Young Lee, told The New York Times, "In people without dementia and without alcohol abuse or dependency, moderate drinking appears to be helpful as far as brain health is concerned."5
Other Brain Benefits of Moderate Drinking
Other studies have also found benefits to moderate amounts of alcohol on the brain, including one published in the journal Scientific Reports.6 While high alcohol exposure increased brain inflammation and impaired function of the glymphatic system, which removes waste products from the brain, acting as a "brainwide metabolite clearance system,"7 moderate drinking had the opposite effect.
Surprisingly, drinking the equivalent of about 2.5 alcoholic drinks a day not only reduced brain inflammation in mice but also increased function of the glymphatic system.8 By pumping cerebral spinal fluid through your brain's tissues, your glymphatic system flushes waste from your brain back into your circulatory system and liver for elimination.
The findings should be taken with a grain of salt, with researchers noting, "Naturally, this study performed in mice should not be viewed as a recommendation for alcohol consumption guidelines in humans."
What's more, there's still much to be learned, as while low-to-moderate alcohol intake has been associated with a lower risk of dementia, heavy drinking may enhance cognitive decline. Further, the researchers noted, "Daily intake of alcohol for 30 years at doses scalable to those in the present study reduces human hippocampal volume by 3.4% to 5.8% compared to abstainers."9
Adding to the controversy over whether or not modest amounts of alcohol are a good thing, a study of 9,000 adults that took place over 23 years found a sweet spot of sorts in terms of alcohol consumption and dementia.10
Both heavy drinkers and abstainers had a higher risk of dementia than moderate drinkers, which was defined as no more than 14 units of alcohol a day, or roughly one medium-sized glass of wine or pint of beer daily. Separate research found that light-to-moderate alcohol intake, especially wine, was associated with larger total brain volume, suggesting it is potentially beneficial for brain aging.11
Is Moderate Drinking Harmful?
Despite some of the positive findings, I do not recommend chronic drinking, regardless of the amount. As demonstrated in the BBC investigation above, drinking tends to do far more harm than good, even if you're within guidelines for "moderate" alcohol consumption.
In the film, using identical twin brothers as guinea pigs, they each drink 21 units of alcohol over differing time scales — one consumes them all in one night while the other has three drinks per day over the course of a week. Twenty-one units amounts to three-quarters of a bottle of whiskey, two bottles of wine or 10.5 pints of beer.
The test continues for a month. Medical tests before and after assesses the physical effects and potential damage. Overall, the tests reveal that alcohol consumption is quite detrimental in general, no matter how it's consumed. Even the doctor was surprised at how bad moderate drinking was, considering it's within the U.K. guidelines for alcohol consumption.
Whether or not a smaller amount of alcohol would have had a different effect is unknown, but there exists a wealth of data showing that alcohol can damage your body, including your brain.
Daily Drinking Accelerates Brain Aging
Drinking even 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.12
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.
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.
A 2019 review published in Frontiers in Neuroscience also 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."13
Does Alcohol Really Reduce Alzheimer's Risk?
As mentioned earlier, heavy drinking may contribute to the development of Alzheimer's,14 but the featured study suggested that moderate drinking may decrease the condition. However, this was based on the finding that alcohol consumption reduction beta-amyloid in the brain. Whether or not this translates to a reduced risk of Alzheimer's is also controversial.
With no known cure, researchers are scrambling to find Alzheimer's treatments, often with a misguided focus on drugs designed to remove excess beta-amyloid in the brain. Drug development for Alzheimer's has so far been a dismal failure, with 300 failed trials to date.15
Now, with experimental drugs failing to lead to improvements, researchers are asking if the focus on drugs to target and neutralize beta-amyloid in the brain is all wrong, and other potential targets should become the focus of future research.16
The reason why beta-amyloid drugs continue to fail to improve Alzheimer's disease, however, is because beta-amyloid is a symptom of Alzheimer's — not the cause. And when you consider this, then it's possible that moderate drinking may not actually reduce Alzheimer's risk just because it reduces beta-amyloid deposits.
Alzheimer's has many causes, as discussed by Dr. Dale Bredesen, professor of molecular and medical pharmacology at the University of California, Los Angeles School of Medicine, and author of "The End of Alzheimer's: The First Program to Prevent and Reverse Cognitive Decline."17
Bredesen's ReCODE protocol evaluates 150 factors, including biochemistry, genetics and historical imaging, known to contribute to Alzheimer's disease. This identifies your disease subtype or combination of subtypes so an effective treatment protocol can be devised. An algorithm is used to determine a percentage for each subtype based on the variables evaluated, and an individualized treatment protocol is created.
Exercise Is Important if You Drink Alcohol
Exercise is important for everyone, but if you consume alcohol getting physical activity may help to buffer some of alcohol's ill effects. According to a report published in the International Review of Neurobiology:18
"There are vast literatures on the neural effects of alcohol and the neural effects of exercise. Simply put, exercise is associated with brain health, alcohol is not, and the mechanisms by which exercise benefits the brain directly counteract the mechanisms by which alcohol damages it."
Indeed, chronic drinkers who exercise regularly have less damaged white matter in their brains compared to those who rarely or never exercise.19 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,20 including reducing some of the cancer and all-cause mortality risks associated with alcohol drinking.21
Should Moderate Alcohol Be Advised for Brain Health?
Even though some research suggests moderate alcohol intake may have a protective effect on some measures of health, I do not recommend drinking alcohol, especially if your purpose is to obtain better health. There are many other foods and beverages you can consume that are linked to positive brain health but do not have the corresponding downside that alcohol does.
Whole, healthy foods are best when it comes to protecting your brain, and this includes foods like animal-based omega-3 fats, cruciferous vegetables and leafy greens, pastured organic eggs and blueberries.
As for beverages, organic coffee and tea consumption has shown some promise, and drinking one to two cups of coffee daily may lower your risk of Alzheimer's disease and other forms of dementia, cognitive decline and cognitive impairment compared to drinking less than one cup.22
If you choose to drink alcohol, keep your consumption to moderate levels or less, and if you don't, do not feel compelled to start drinking to stay healthy — there are plenty of other ways to do that.