In January 2023, the Canadian Centre on Substance Use and Addiction (CCSA) announced new guidance for alcohol consumption.
Its previous guidance provided limits for alcohol use to reduce long-term health risks, such as no more than 15 standard drinks for men and 10 standard drinks for women per week. But in a stark change, the new guidance says that consuming more than two standard drinks per week is risky for both men and women — and that no amount of alcohol is safe.
In Proof: The New Science of Alcohol, host Anthony Morgan embarks on a journey to learn more about what the evidence has to say about the risks of moderate drinking, speaking to alcohol researchers around the globe.
“It was interesting to see how quickly the science can evolve on these kinds of things,” Morgan told CBC Docs. “We used to believe really strongly that alcohol could be protective, and now, not so much at all.”
Revisiting the data
The CCSA’s new guidance for alcohol use are, for many people, surprising. What about the headlines of yesteryear touting the benefits of a glass of wine for our health?
Those claims were based on observational studies that produced what researchers call a J-curve, says Dr. Gautam Mehta, an alcohol-related liver disease researcher at University College London who speaks with Morgan in the documentary.
Mehta explains that when alcohol use was plotted against mortality, the people with the lowest mortality were those who consumed alcohol in moderation. The highest mortality was found in heavy drinkers, and people who drank no alcohol had slightly higher mortality than those who drank in moderation.
But what these studies didn’t take into account is the history of those individuals and their drinking behavior in the past. “That was quite a big miss into how these studies were designed and how data was collected,” he says.
The teetotalers included people who were sober because they had to be — people who stopped drinking because, as Morgan puts it, “they drank so much it was killing them.” When you remove those people from the data, you get a straight linear correlation: zero alcohol consumption was associated with the lowest mortality.
While Mehta says that there may be “subtle benefits in diabetes risk and cholesterol,” he tells Morgan that any benefit to alcohol consumption is “completely outweighed” by the risks that it presents.
The CCSA guidance was updated to reflect these new findings and other emerging research on drinking (the official Health Canada guidelines remain unchanged and are still in the process of being updated, a ministry official told The Canadian Press earlier this year).
Even moderate drinking linked to cancer
According to the CCSA, your risk of developing several types of cancer, including breast and colon cancer, increases at three to six standard drinks per week.
“The majority of Canadians have no idea that their favourite recreational drug is a carcinogen,” Tim Stockwell, a researcher at the Canadian Institute for Substance Use Research at the University of Victoria, tells Morgan in the film.
Since 1987, alcohol has been classified as a Group 1 carcinogen (carcinogenic to humans) by the International Agency for Research on Cancer, the World Health Organization (WHO)’s cancer research agency. This is the highest risk group, which also includes asbestos, solar and ultraviolet radiation, and tobacco.
The majority of Canadians have no idea that their favourite recreational drug is a carcinogen- Tim Stockwell
And according to a 2023 WHO news release, light to moderate drinking accounts for about half of all alcohol-attributable cancers in Europe.
In Proof, Stockwell describes a brief experiment with cancer and other health-warning labels on alcohol — similar to those on cigarette packages. In 2017, bright yellow and red labels were placed on alcohol containers at a government liquor store in Whitehorse.
“Within 29 days, the alcohol producers in Canada threatened legal action against the Yukon government,” Stockwell says.
WATCH | Alcohol warning labels:
Warning labels on alcohol caused sales to drop — until the alcohol industry pushed back
When yellow and red labels were placed on alcohol at a liquor store in Whitehorse in 2017, sales of labelled products dropped 6.6 per cent. The labels were removed after local alcohol companies and alcohol industry associations pushed back. Learn more in Proof: The New Science of Alcohol.
“The industry is saying there isn’t enough evidence that alcohol causes cancer,” Kara Thompson, a youth substance use and mental health researcher at St. Francis Xavier University, tells Morgan. “That’s not true. There’s lots of evidence that alcohol causes cancer.”
What does alcohol offer us, and can we replicate these effects?
While the CCSA’s updated guidance is clear that no amount of alcohol is good for your health, what about the perceived social benefits of drinking?
Ask the average pub-goer what they gain from drinking, and they’re likely to say that alcohol can loosen them up and provide a helpful sense of ease. The documentary follows researchers who are studying this “social lubricant” effect of alcohol.
Catherine Fairbairn is a researcher in the Alcohol Research Lab at University of Illinois Urbana-Champaign. “There have been a number of studies that have looked at alcohol’s acute effects on the brain. However, almost none of them have featured any sort of social context,” she says.
If researchers can understand the social effects of alcohol, it’s possible that we could find other ways to encourage the social lubricant effect without having to involve alcohol at all, says colleague Kara D. Federmeier, director of the Cognition and Brain Lab at the university.
Knowing more about what alcohol does for people in a social context can also help us better understand what could lead to addiction, says Fairbairn.
Morgan participated in an experiment that uses brain-scanning to study alcohol and social interactions. (Sofi Langis)Experts want you to understand the risks of moderate drinking
Most of the experts in the film don’t advocate for total abstinence. Instead, they simply want people to be aware of the risk they are taking.
For years, it was believed that moderate alcohol consumption had health benefits. But research suggests there are risks even at moderate use, from cancer to cognitive decline.
‘What the science tells us — and this kills me to say — is that alcohol has more severe health risks than we once thought,’ Morgan says in the documentary. ‘There is no safe level of alcohol.’ (Van Royko)
“I started this journey by wanting to understand what the science says about the consequences of drinking,” Morgan says in the documentary. “I realize that like any good field of study, the process is ongoing.”
For now, Morgan hopes Proof: The New Science of Alcohol will help give viewers a better understanding of the risks of drinking so they can make their own choices about their health.
“I’d say the main takeaway people should get from this documentary is that yes, unfortunately it is true that there is no safe level of alcohol to consume,” Morgan told CBC Docs.
“But that doesn’t mean you have to give it up entirely. The choice is still yours, and really the important thing is that your choice is an informed one.”
Watch Proof: The New Science of Alcohol on CBC Gem and on the CBC Docs YouTube channel.