Story highlights

Scientists did a review of 87 studies about health and alcohol

They didn't see the positive health impact some headlines tout

There may be a bias in how the studies group drinkers

CNN  — 

Now here’s some news that may have you crying into your beer. Alcohol, when consumed in moderation, may not improve your health after all.

Over the years we’ve all seen the studies that show a glass of wine a day may help protect you from developing heart disease, will help with cancer and keep type 2 diabetes away, and will ultimately help you live longer. But this new research may be a buzz kill for those who like to drink in moderation. Toasting to your health may actually be an oxymoron.

So, belly up to the bar and we’ll explain what the scientists behind this new meta-analysis running in the latest edition of the Journal of Studies on Alcohol and Drugs think happened with the earlier studies that show the health benefits of moderate drinking.

This team of scientists looked at a wide variety of studies on the topic, specifically looking at alcohol’s impact on mortality. Narrowing their list down to 87 studies, the authors found the majority of them may have been coming to conclusions based on what the authors label as “biased” data.

It’s not that the other scientists were working under the influence of the industry or something more potent. This latest study found that when those other studies divide people into groups they typically put them into common categories: heavy drinkers, moderate drinkers, occasional drinkers and abstainers.

What the new study found is that the abstainer group isn’t only made up of people who have never touched a drop. Instead, some in this group may be recovering alcoholics. Some may also be abstaining now because of a health condition. In general, those two groups of people in the abstainer category are not as healthy as those who are lifelong teetotalers, research shows. That means these less healthy people skew the data. So, the moderate drinkers end up looking healthier by default. Make sense?

Of the 87 studies, 13 did separate out the lifelong abstainers from the former drinkers. The studies that controlled for these sicker people found that moderate drinkers had no health advantage over the true nondrinkers. When this team reran the data they considered appropriate against other studies, using these much narrower definitions of abstainers, they saw the same results: The moderate drinkers were no better off than the abstainers.

You may be wondering: Why does this matter to anyone other than the scientists who study alcohol?

“Alcohol has played such a central part of many people’s lives and is embedded in various occasions and relationships, so there is a lot of interest on this topic,” said co-author Dr. Tim Stockwell. “Understanding this question is important as we shape alcohol policy.”

Some earlier studies have also chipped away at the idea that there are health benefits to moderate drinking. A study that ran in BMJ last year suggested there was no sign that you lived longer because you drink a little as opposed to abstaining. Other studies have come to different conclusions, showing some benefits. (If you are a heavy drinker, that’s a different story. Your life will likely be shorter.)

“Determining how a low dose of alcohol impacts your life is complicated work,” said Aaron White, the senior scientific adviser to the director of the National Institute on Alcohol Abuse and Alcoholism. He said relying on self-reported data, remembering how much you drank a month ago, is difficult. There is a real need for randomized control trials to truly see what impact drinking has on human health.

The Centers for Disease Control and Prevention guidance on drinking hedges its bets a little and mentions that recent studies have called the health benefits of drinking into question, while still offering guidance that there could be some protective qualities to drinking. The guidance adds that you shouldn’t start drinking for your health. It also suggests essentially that it is impossible to separate the drinking from other components in someone’s life that may make them healthier than others. That means moderate drinkers may also be watching their diets or be healthier in general and that may lead to a longer life.

White said there is “considerable” lab data that shows a small amount of alcohol may be beneficial for health in terms of reducing inflammation and helping with cardiovascular health and stroke reduction. To see these effects, however, requires “taking alcohol like you would take medicine, in small doses.” And it would be rare for a doctor in the 20 minutes they have with you in an appointment to give you this nuanced kind of advice.

Dr. Kenneth Mukamal, who is an associate professor of medicine at Harvard’s School of Public Health who has no affiliation to the study, said he thinks the authors defined the categories of drinkers and nondrinkers too narrowly and that focusing on studies that look strictly at mortality may also be too narrow.

“At this point we still don’t have the level of proof that we want,” Mukamal said. “This is a little overstated.”

To determine if moderate drinking is good or bad for your health will take true clinical trials rather than observational studies, he said.

And before you go and drown your sorrows about this news, perhaps you can look at what this new study is not saying. The study is not telling you that an occasional drink is bad for you. Ultimately, what this study is saying is that there are limitations to what we know. It’s possible that abstainers and moderate drinkers may have similar long-term health results.

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    There are many additional studies that show heart-protective effects of alcohol and other studies show that there are psychological benefits to having a drink every once in a while as stress relief.

    Other studies show that drinking can increase a risk of breast cancer in women. So, if you plan to debate this at your local tonight, take the current study author’s advice to heart.

    “My advice: Drink for the enjoyment, sure,” Stockwell said. “But just don’t kid yourself that you are doing it for your health.”