why the research on whether drinking alcohol is healthy for you keeps evolving

People have been drinking booze for thousands of years, but scientific thinking on the benefits and risks of alcohol has shifted of late.

Until recently, doctors said moderate drinking was healthy. Now, research is increasingly finding that any level of alcohol is dangerous. Even moderate drinking is linked to higher levels of heart disease, high blood pressure, liver disease, and certain cancers.

The topic is hardly settled. There are still doctors and scientists who say moderate alcohol consumption offers some benefits and others who say the question can’t be answered with current research.

Barron’s talked to several experts to get the latest thinking on alcohol consumption and why it has evolved. What diseases are most linked to alcohol? Who shouldn’t be drinking? How much can the rest of us drink while having minimal effect on our health? And how can we tell if we’re drinking too much?

Here’s what we learned.

Why Has the Scientific Consensus on Alcohol Shifted?

There are two main reasons scientists say past research comparing the health of nondrinkers and moderate drinkers may have been misleading.

First, the group of nondrinkers studied in past research included people who don’t drink because of health problems. It also included people who formerly had drinking problems and stopped drinking. These are two populations that are both unhealthier than moderate drinkers, so if they weren’t excluded, they tended to drag down the numbers for the entire group of nondrinkers.

The other reason is the favorable demographics of the moderate drinkers included in these studies. They are often more affluent than nondrinkers, and affluent people tend to live longer. Many moderate drinkers exercise regularly and don’t smoke—two other factors that are strongly linked to a longer, healthier life.

When you adjust for these factors, past research on the benefits of moderate alcohol consumption looks less compelling.

“Over the last decade, more and more scientists have concluded the apparent health benefits [of moderate alcohol consumption] fall apart if you look at them closely,” says Tim Stockwell, who has done alcohol research at the Canadian Institute for Substance Use Research in British Columbia, Canada.

Why Hasn’t the Question Been Settled?  

A number of experts say research produced to date isn’t conclusive one way or the other. Cardiologist Gregory Marcus of the University of California at San Francisco notes that most of the studies on the benefits of alcohol have been observational rather than the gold standard of randomized controlled studies.

Observational studies can be skewed by confounding factors. Just as the original research was skewed by demographic factors, the new research that has found no benefit to moderate alcohol could be skewed by other factors. For example, it is possible that nondrinkers also do other things that make them healthy besides abstaining from alcohol.

“I’m not claiming alcohol has beneficial effects,” Marcus says. “An honest scientific evaluation would conclude there isn’t strong evidence one way or another.”

So Is It OK to Drink Alcohol or Not?

Scientists may not reach a definitive answer for a long time. But here’s the key: Even those studies and researchers who say any level of alcohol is unhealthy usually conclude that moderate drinking isn’t very unhealthy.

That Helps. What Is Considered Moderate?

The standard definition has been no more than one drink a day for women and no more than two drinks a day for men. Now some research says the limit should be one drink a day for everyone. (In the U.S. one drink is defined as 14 grams of pure alcohol, which is roughly equivalent to 12 ounces of beer, five ounces of wine, or 1.5 ounces of distilled spirits.)

Carl Lavie, a cardiologist at the Ochsner Heart and Vascular Institute in New Orleans, is among those who believe there are benefits to moderate alcohol consumption. What does he tell his patients? “Try to keep the dose low, not more than one to two drinks per day or three to five per week.”

Why the Difference Between Men and Women?

Men tend to be bigger and more muscular than women. Muscles retain more water, which helps dilute the effects of alcohol. Though it may ultimately come down to size.

“It takes less alcohol in a smaller person to raise blood alcohol content,” Marcus of UC San Francisco says.

Are Women More at Risk?

Women who drink excessively are more prone to heart disease, liver disease, and brain damage than are men. Even light drinking raises women’s chances of developing breast cancer or uterine cancer, research indicates.

What Problems Do Men Encounter?

Even though men tend to be less affected by the same quantity of alcohol than women, they usually drink more and thus experience more alcohol-related illnesses than women. Such illnesses include heart disease, high blood pressure, stroke, liver disease, and a bunch of different cancers.

Why Does Alcohol Cause Cancer?

You know how we’re all told to eat foods with antioxidants for our health? Those foods protect against inflammation and cell damage from oxidants. Alcohol is just that: an oxidant, says Suneel Kamath, an oncologist at the Cleveland Clinic. “It causes damage to the DNA in our cells,” he explains. The more damage, the more likely cells will mutate when they regenerate, giving birth to a cancer.

Many of the cancers most linked to drinking are in the gastrointestinal tract: those of the tongue, throat, esophagus, and stomach, Kamath says. Drinkers are also prone to cancer of the liver. But alcohol affects the entire body. “It’s sort of a global carcinogen,” he says.

Should Some People Not Drink Alcohol at All?

The obvious answer is that people with drinking problems and pregnant women should abstain. People who have balance or gait problems and have taken falls shouldn’t drink; the same for people who need walkers. “That person should never drink,” says Dr. Stephen Holt, an addiction specialist at the Yale School of Medicine.

And some particular health problems can be aggravated by drinking. For example, people who have atrial fibrillation (AFib) are more likely to experience episodes if they drink. Read this Barron’s article for more on that.

People “who feel terrible with AFib and are trying to avoid an ablation at all costs” shouldn’t drink, says Lavie, the New Orleans cardiologist. (An ablation is a procedure performed on people with AFib to get their hearts beating again in a proper rhythm.)

How Can I Tell if I’m Drinking Too Much?

Holt of Yale has a simple test: Go without drinking for a month. “If you find you are unable to do that, you just might have a drinking problem,” he says.

Will Drinking Make Me Die Younger?

Likely yes. But not as much as you might think. If a man drank one drink a day starting at age 15, it would lower his life span by an average of 11 weeks, according to a calculation by researcher Stockwell using numbers from Canada’s Guidance on Alcohol and Health. Two drinks a day lowers a life span by 36 weeks; three drinks by 58 weeks, four drinks by 90 weeks; five drinks by 129 weeks.

Indeed, many alcohol researchers are light drinkers. Stockwell drinks three or four drinks a week on average and doesn’t worry that it might shorten his life by a few weeks.

He notes that alcohol consumption has been around almost as long as humans. “Neolithic hunters apparently made some kind of ale as they were sitting around their fires,” he says.

Write to Neal Templin at neal.templin@barrons.com

Source: Barrons https://www.barrons.com/articles/drinking-alcohol-health-research-c2e241be?st=XNucxg&reflink=desktopwebshare_permalink