When it comes to how alcohol affects your health, guidance — from how drinking affects pregnancy to whether sipping red wine helps your heart — is all over the map.
Now, a new major multinational study has another piece of advice: People who consume more than about six drinks per week have a greater risk of premature death.
The study published Thursday in the Lancet analyzed data from 600,000 people who drink zero to more than 350 grams of alcohol per week. It found that people who drank more than 100 grams of alcohol per week, the equivalent of about six glasses of wine, had increased risk of stroke, heart disease, heart failure, fatal hypertensive disease and fatal aortic aneurysm.
What exactly does that mean?
Look at it this way. If a 40-year-old man reduced his weekly alcohol intake from 196 grams (the current alcohol guideline for men in the United States) to 100 grams, he could expect to live as much as two years longer, the study says.
Some studies have suggested drinking moderate amounts of red wine is good for cardiovascular health, but what does moderate mean? That’s one question Angela Wood, who studies epidemiology and lectures at the University of Cambridge, and her team tried to figure out.
It’s a question that’s also long been debated among alcohol researchers. It’s hard to develop a one-size-fits-all recommendation because how alcohol affects the body can vary from one person to another. In certain studies, “moderate” is one drink a day; in others, it’s as many as three or four a day, researchers at Harvard’s School of Public Health have pointed out.
The bottom line: “Any supposed benefits in health should be balanced against that shortened life expectancy,” Wood said.
The research: To land on the magic number of 100 grams a week, researchers analyzed 83 studies on alcohol consumption pulled from the Emerging Risk Factors Collaboration, European Prospective Investigation into Cancer and Nutrition and the UK BioBank.
They spanned nearly 50 years and 19 high-income countries where alcohol drinking guidelines vary greatly, especially in the United States, Portugal and Spain. This allowed researchers “to characterize risk thresholds for all-cause mortality and cardiovascular disease subtypes in current drinkers of alcohol,” the authors wrote.
Still, the study had its limitations, including potential bias from self-reported survey data from people who about how much alcohol they drank, the authors said. And because they did not have more data from all stages of each survey participant’s life, the authors conceded that they “probably under-estimated potential benefits associated with lowering alcohol consumption.”
How do these findings match up with current guidance?
Researchers in a 2016 study from Stanford said “that what constitutes a ‘standard drink’ in each country is far from standard,” yet “in many cases these guidelines are adopted as public health policy and even printed onto alcoholic beverages without knowing whether people read them, understand them or change their behavior as a result.”
For instance, Australia doesn’t offer different alcohol guidance to men and women, while many other countries do. And “the upper weekly limit for men in Poland is substantially higher, at 280 grams per week,” the Stanford study found.
“Inconsistent guidelines are also likely to increase skepticism among the public about their accuracy. It is not possible that every country is correct; maybe they are all wrong,” researchers wrote.
In 2016, the United Kingdom lowered its alcohol drinking guidelines to 14 units of alcohol (or five pints of beer) per week, but Wood said it is too soon know what effect, if any, that change has had on the country’s overall public health.
According to the latest U.S. dietary guidelines, updated every five years and again in 2020, women should drink no more than one serving of alcohol per day; men can drink up to two. Those guidelines have defined moderate alcohol consumption for more than two decades, said Samir Zakhari, a former scientist from the National Institute for Alcohol Abuse and Alcoholism who now oversees scientific affairs for the Distilled Spirits Council, an industry lobbying group.
“These guidelines form the basis of federal nutrition policy and programs and help guide local, state, and national health promotion and disease prevention initiatives,” he said in an email to the NewsHour.
But recent research has suggested that Americans need to reassess how much they drink. In January, the National Academies of Sciences, Engineering and Medicine produced a report that explored ways the United States could lower death and injuries linked to alcohol-impaired driving. The report, produced in part by Tim Naimi, an associate professor of medicine who studies public health and alcohol at the Boston University School of Medicine and Public Health, said the U.S. has kept taxes on alcohol low and poorly enforces laws governing alcohol consumption.
The United States should lower the legal blood-alcohol concentration from 0.08 percent to 0.05 percent, the committee suggested.
Two decades ago, the nation lowered the legal driving limit for blood-alcohol concentrations from 0.10 percent to 0.08 percent. At that time, nearly 16,000 people died in alcohol-related traffic accidents, amounting to more than a third of all traffic fatalities. Iny 2016, with a lower legal limit, alcohol played a role in 10,400 people’s deaths.
“Even among alcohol researchers, there’s no universally accepted standard drink definition,” researchers at Harvard say. It’s unclear what impact this study will have. But the U.S. dietary guidelines are set to be updated again after 2020. The study could prompt U.S. public health experts to rethink how alcohol fits in the American diet and what it means to drink in moderation, Naimi said.
“We need to do a lot better,” Naimi said. “People’s health and the wellbeing of communities is in the balance.”