Just in time for cocktail hour last Friday, the World Health Organization released a mammoth report on the health impacts of drinking. While reinforcing public health experts' image as Debbie Downers, the report lays out a compelling case for teetotaling. For those whose eyes have trouble focusing on the full report, there's an accompanying press release, and also a handy tweet storm to access at the bar.

You may have a drinking problem if...

But doesn't all this anti-ethanol advocacy fly in the face of solid data showing the benefits of an occasional drink? In short, no. While a significant body of research claims that moderate drinking might reduce the risk of some problems, especially heart disease, there's an equal and opposite body of research showing no benefit. Unfortunately, the former group of papers gets a lot more news coverage, because they combine the frisson of a slightly counterintuitive claim with validation of a guilty pleasure the reader most likely enjoys. Telling people "that fun thing you feel bad about is actually good for you," is a great way to attract eyeballs and social media links.

Given the apparent controversy, and people's desire to continue drinking, there's a tremendous temptation to throw up our hands and just keep doing what we're doing. So why did the WHO come down so hard on Dionysus? The science, it turns out, isn't as unsettled as it appears.

Studies on alcohol consumption fall into two broad categories: population surveys and mechanistic experiments. In the population surveys, researchers ask people how much they drink, then see how that correlates with health outcomes such as heart disease, liver disease, and overall mortality. All of these analyses show that heavy drinking is bad, but at the lower end of the consumption scale a strange thing happens. People who drink a little bit, averaging no more than one or two drinks a day, seem to be healthier than those who abstain completely.

This is where we need to back up and ask about confounding factors. Who's in the population of non-drinkers? Lots of those folks just don't like alcohol, but quite a few others are on the wagon for medical reasons. Liver transplant recipients, former alcoholics, and people taking a wide range of powerful prescription medicines are all likely to avoid drinking, because if they imbibe they'll probably die. Those people are, on average, not very healthy. The "moderate drinking" group excludes those populations, which may be the main reason they seem healthier. Studies that account for this discrepancy are far less likely to find alcohol beneficial.

Mechanistic experiments claiming to show the benefits of drinking run into a different set of problems. Many of these studies focus on compounds in red wine. Researchers performing these studies usually claim that's because red wine is a popular and ancient drink. Cynics point out that it's particularly popular among the powerful upper-middle-class demographic most likely to help a study aboard the hype-wagon, so researchers may be picking it to maximize their odds of publicity. Red wine indisputably contains higher concentrations of some antioxidant compounds, though, including one extremely well-promoted one called resveratrol.

There are at least four problems with taking a daily resveratrol dose in fermented form. First, there's no good evidence from human studies showing resveratrol works against any of the conditions it's supposed to combat, and people have looked hard. Second, the concentration of resveratrol in red wine is so low that one would have to ingest lethal doses of wine to approach the allegedly therapeutic levels tested in cell culture and animal models. Third, the antioxidants found in red wine are also found in unfermented grape juice, so there's no compelling argument in favor of wine over a non-intoxicating alternative. Finally, alcohol is a known toxin. Even if resveratrol was proven to be beneficial at the vanishingly low concentrations in wine, why take a poison along with it?

That brings us to the crux of the problem with the alcohol-as-health-food argument. Even if all of the claimed benefits of alcohol were real, which they aren't, we'd have to weigh them against the risks, and oh boy are there risks. In the US alone, five million emergency room visits a year stem from drinking, and that number is going up. The new WHO report estimates one in twenty deaths worldwide is a result of alcohol abuse, while almost 300 million people suffer from alcoholism and related disorders. That's a serious buzz-kill.

The disinhibiting effects of alcohol also increase the risk of unwanted pregnancy, sexually transmitted diseases, and becoming the victim or perpetrator of a crime. Though not tracked in official statistics, drinking also drastically increases the odds of simply making an ass of oneself. Not that I know anything about that.

Given all that, it's safe to say that alcohol is, on balance, bad for public health. What's less clear is what we should do about it. Outlawing it didn't work out. Raising the legal drinking age to 21 seems to have been a good idea, though there's still a lot of underage consumption going on. The new WHO report continues a long tradition of public health officials exhorting people to drink less, but it's difficult to say what effect these periodic reminders have.

Alcohol has been part of human culture for about as long as there's been human culture. The oldest recorded image of beer o'clock dates back 6,000 years, and it's likely people were visiting the pub long before that. Perhaps the best perspective is the one summarized in this pithy British quote regarding another recent alcohol toxicity study:

Yet Prof David Spiegelhalter, Winton Professor for the Public Understanding of Risk at the University of Cambridge, sounded a note of caution about the findings. "Given the pleasure presumably associated with moderate drinking, claiming there is no 'safe' level does not seem an argument for abstention," he said. "There is no safe level of driving, but the government does not recommend that people avoid driving. Come to think of it, there is no safe level of living, but nobody would recommend abstention."

So don't drink, or drink a little because you enjoy it. Just don't expect science to rationalize it for you.

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