The relationship between alcohol and dementia has been studied widely. Most of epidemiological studies have consistently reported that compared with non-drinkers, light to moderate drinking exhibits a reduced cardiovascular risk, showing a J–shaped relationship, which by extension means that risk of mortality is higher among non-drinkers, lowers among moderate drinkers and increases with heavy drinking.
That said, it’s important to realize what alcohol does to our brain.
When we drink alcohol, it starts being absorbed into the blood stream through the mucus membranes in our mouth before heading on into the small intestine, and then passes to the liver. The liver has the enzymes that can break down alcohol, as its job is to transport toxins out of the body, and alcohol is one of them. But the liver doesn’t break it down completely in first pass and much of the alcohol reaches other organs such as the pancreas, muscle and bones, including the brain. It takes just a few minutes for the alcohol to arrive in the brain and causes disinhibition. Short term, it may not kill neurons but long-term, it has been associated with decreased cognitive function and memory issues. It could also disrupt vitamins and trace elements that play a large role in the sustained health of the central nervous system.
Age is also a factor. Alcohol could be a neurotoxin with direct effects on neurons, stalling neurogenesis in adolescents and children (fetal alcohol syndrome), but this effect is not seen among older adults. We’ve known for a while that brain atrophy is common among heavy drinkers. But a comprehensive 2017 study found that even moderate drinking can lead to atrophy of the brain, especially in the hippocampus, which is the area of the brain that’s associated with encoding memory. And the degree of atrophy was directly related to the amount of alcohol consumed – people who drank the equivalent of four drinks a day had almost six times the shrinkage as nondrinkers. Moderate drinkers had three times the risk of shrinkage than nondrinkers. Chronic alcohol abusers were at additional risk for brain injury from related causes, such as falls, head injuries, poor nutrition profile and liver disease.
But how much is too much? Here’s the definition of “a drink” according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA):
- 1.5 ounces of 80-proof spirits, roughly a shot
- 12 ounces of beer at around 5% alcohol, the equivalent of a standard can
- 8 ounces of malt liquor, about three quarters of a pint glass
- 5 ounces of wine at around 12% alcohol, roughly a half glass
- Moderate drinking is typically defined as 1 drink a day for females and 1 or 2 drinks a day for males.
- Heavy drinking is typically defined as more than 3 drinks on any day or more than 8 drinks a week for females. For males, it’s more than 4 drinks on any day or more than 15 drinks a week.
- Binge drinking is typically defined as 4 drinks within 2 hours for females and 5 drinks within 2 hours for males.
In summary, alcohol doesn’t kill brain cells, but it does have both short- and long-term effects on your brain, even in moderate amounts. If you don’t drink, there is no reason to start drinking for better brain health, as you can focus on so many other safer factors to boost your brain. If you like an occasional beer or wine, you likely won’t cause any long-term damage. But if you drink more than the above-mentioned amount, then you should reconsider.
Further reading: Costanzo, S., de Gaetano, G., Di Castelnuovo, A., Djoussé, L., Poli, A., & van Velden, D. P. (2019). Moderate alcohol consumption and lower total mortality risk: justified doubts or established facts?. Nutrition, Metabolism and Cardiovascular Diseases, 29(10), 1003-1008.