For many years, the prevailing belief was that alcohol wasn’t necessarily bad for you – and that drinking in moderation might even offer certain health benefits.
But a new study published in BMJ Evidence-Based Medicine is challenging that idea, showing that even small amounts of alcohol could raise the risk of dementia.
Their findings suggest that even light or moderate drinking may have harmful effects on brain health.
Heavy drinking – defined as consuming more than 12 alcoholic beverages per week – has long been linked to dementia, an umbrella term that describes several cognitive disorders that impair memory, reasoning, and thinking, including Alzheimer’s disease.
For years, however, it was widely believed that moderate drinkers – those who had about one drink per day – had a lower risk of dementia compared to those who did not drink at all.
That idea mostly comes from a well-known 2003 study published in JAMA.
Joel Gelerntner, who led the 2003 study and teaches at Yale’s School of Medicine, used to take that advice himself – having a drink a day because the science at the time suggested it was good for you.
Now, however, with a growing body of evidence showing the opposite, Gelerntner says he’s cut back significantly.
Even a Small Amount of Alcohol Has Its Risks
Older studies – most of which relied on people reporting their own drinking habits – often found that nondrinkers had a slightly higher risk of dementia, while moderate drinkers seemed to have the lowest risk.
But using self-reported data comes with various problems.
In an ideal world, a randomized controlled trial would be the best way to determine causation, but such an approach wouldn’t be ethical or realistic.
So instead, researchers turned to the next best approach.
They analyzed genetic data from 2.4 million people to estimate how much alcohol a person is likely to drink over their lifetime, allowing them to more clearly link drinking habits to dementia risk.
They found that the more alcohol a person drinks, the higher their risk of developing dementia.
Specifically, a threefold increase in alcohol consumption was linked to a 15 percent higher lifetime risk of dementia.
How Alcohol Affects the Brain
Alcohol easily crosses the blood-brain barrier after consumption.
Once in the brain, it boosts neurotransmitters that suppress neural activity and that triggers a release of dopamine – the chemical behind that pleasurable “buzzed” feeling.
While the short-term effects of alcohol are well studied, researchers are still studying its long-term, impact on the brain.
