Although we all know that binge drinking is bad for our health, the research underpinning moderate drinking is still a work in progress.

At least from a public-relations standpoint, the world of alcohol research appears to be a little jumbled at the moment.

A study published in the journal Nature in March appears to provide some of the strongest evidence yet that even moderate drinking can impair the brain.

After analyzing brain scans from over 36,000 middle-aged and older people in the UK Biobank, scientists found that 50-year-olds who consumed an average of one 175 milliliter (6 oz) glass of wine or half-liter (roughly 1 US pint) can of beer per day for the previous year had brains that appeared 1.5 years older than counterparts who consumed half that amount or none at all.

According to the study, drinking alcohol causes you to age faster.

The research is one of the greatest to date on the effects of moderate drinking on the brain’s health. Moderate drinking was defined as up to 14 drinks per week, whereas light drinking was defined as more than one drink per week but less than seven.

However, many questions remain unanswered.

The study

Though the brain study’s findings appear easy at first glance, a closer examination reveals just how much we still don’t know.

Patricia Molina, director of the Alcohol and Drug Abuse Center of Excellence at Louisiana State University, noted that it remained unclear what the effects of two years of brain shrinkage — which caused the appearance of aging —  were on cognition and behavior.

She claims that there is a link between brain volume decrease and cognitive impairment based on several lines of research. She is also unaware of any clear research that shows a direct link between certain percentages of reduced brain volume and clinical manifestations that individuals or their doctors may see.

The study’s design also made it impossible to address questions about how the findings compare to shrinkage caused by other activities and disorders known to cause a decrease in brain matter, such as lack of physical fitness or Huntington’s disease, according to Molina.

“A meta-analysis would be the closest way of getting to the answer,” Molina said.

To put it another way, someone would have to examine the complete body of literature and interpret the results in such a way that such comparisons are possible.

Another reason for the difficulty in making such comparisons, according to Molina, is that different activities or illnesses produce distinct shrinkage in different areas. For example, sitting around all day and simply eating processed foods may promote shrinkage in a different part of the brain than Huntington’s disease.

There’s also the chicken-and-egg problem. Is it possible that those who drink alcohol on a regular basis have smaller brains than those who opt to abstain?

“That is a distinct possibility,” said Molina. “The only way of answering that question is by collecting brain images from early life.”

Scientists are looking to answer this question through the Adolescent Brain Cognitive Development study, Molina added. This study collects data on alcohol and drug usage while tracking changes in brain volumes over time.

Isn’t red wine, on the other hand, healthy?

There is solid evidence that binge drinking is damaging to the body and brain. However, when it comes to moderate drinking, the situation becomes more complicated. A number of research published in recent decades, including one published just a day before the brain study, appear to suggest that moderate drinking is actually beneficial.

The researchers discovered that drinking the alcohol equivalent of roughly 5 ounces of wine with meals per day for women and 10 ounces of wine with meals per day for men was associated with a decreased risk of acquiring type 2 diabetes.

With this type of research, Jeanette Tetrault, a Yale professor of medicine who specializes in alcohol addiction, said it was critical to read below the headlines.

In the end, she explained, the study simply discovered that drinking alcohol with food reduces your risk of developing type 2 diabetes compared to drinking alcohol alone. It’s less about whether or not alcohol is good for you.

“If you don’t read those nuances,” she said, “your interpretations can lead to some significant issues.”

Critics argue that such studies frequently fail to account for crucial socioeconomic factors, and thus promoting the benefits of red wine is inherently biased. That’s because those with a higher socioeconomic standing are more likely to drink a glass of red wine per day than those who aren’t.

Take it slowly and carefully

According to a 2018 New York Times investigation, experts involved in a large-scale 10-year study looking at the influence of moderate alcohol intake on health were extensively lobbied by the alcohol industry.

Major firms in the alcohol business, including Anheuser-Busch InBev, contributed the majority of the $100 million used to pay the National Institute of Health (NIH) study. In emails and conference calls, the study’s primary author, a Harvard professor of medicine, promised alcohol executives that the findings would be favorable to them.

The trial was halted after NIH officials became aware of the problematic techniques. Despite the fact that nothing was published as a result of the incident, it serves as a caution to be skeptical of outcomes that appear to be too good to be true.

So how careful should I be?

A significant study published in 2018 aimed to settle the moderate drinking controversy, concluding that no amount of alcohol consumption promotes health.

The study, which included data from 195 nations over a 26-year period, provided the most complete estimate of the worldwide burden of alcohol to date. However, other scientists have pointed out issues in the study’s design, such as the authors’ use of relative terminology to track their results rather than numbers. When they did provide actual figures, the degree of harm appeared to be debatable at best.

People who had one drink per day had a 0.5 percent increased risk of getting an alcohol-related health problem than those who didn’t. In terms of numbers, the study indicated that if adults between the ages of 15 and 95 did not drink, 914 out of 100,000 would have a disease within a year. If they did, the number climbed by only four people, to 918 people per 100,000.

Given what we now know about alcohol intake, Tetrault stated that she does not advise her patients to abstain entirely. She said she would utilize the brain study as a supplement to counseling with patients who already have underlying issues affecting their cognitive or brain function.

“But I wouldn’t necessarily utilize this data to try to change behaviors in patients who are really having no health consequences [and] know what their potential risks are,” she said. “I’m not telling all my patients they have to abstain.”

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