Yes, even if it's a Bloody Caesar with extra celery: Why even just a little alcohol is a risk

With alcohol-related deaths at an all-time high in Canada, and mounting pressure to put cancer warnings on alcohol containers, Canadians have questions about the specifics after a drastic shift in messaging.

In one fell swoop, an expert group has shifted the safe drinking range from 10 to 15 drinks per week, depending if you are a man or a woman, to fewer than two. Even small amounts of alcohol are now linked to up to nine kinds of cancer, according to the Canadian Cancer Society.

That has some Canadians pointing to aged lifelong drinkers in their family with consternation. 

Dozens of people wrote to CBC News asking just how many and which drinks are a danger and why cancer does not affect all big drinkers.

Dr. Tim Naimi, a physician and the director of the University of Victoria's Canadian Institute for Substance Use Research, understands the confusion.

"We understand that there's going to be anxiety," he said. "A lot of people really, really enjoy drinking alcohol."

Naimi says alcohol needs clearer labels so drinkers know what they are ingesting and understand the risks.

The Boston native said he is surprised that Canadian alcohol does not even report sugar levels, much less cancer risks, despite the fact that booze is "an intoxicating, addictive, carcinogenic thing that kills lots of people."

He believes it's related to the focus on alcohol revenue over safety.

"A can of peas in a supermarket has information about how much magnesium or calcium is in the peas, and those aren't even toxic carcinogenic products," said Naimi.

He said ingesting two standard servings with 14 grams of ethanol — the chemical name for alcohol — per week is OK, but after that health risks increase.

How does alcohol affect the human body?

The journey of alcohol through the human system is explained in an alert issued by The National Institute on Alcohol Abuse and Alcoholism (NIAAA). When a human drinks alcohol, the body works to process and eliminate it.

Enzymes help break apart the ethanol molecule into other compounds that the body can process, but some intermediate steps can damage the body.

Alcohol is metabolized by the brain, the stomach and the pancreas — but mostly by the liver. This organ converts alcohol into a short-lived but toxic compound — acetaldehyde, a known carcinogen — which is then broken down into a less toxic compound. But the speed at which that happens depends on many factors, including metabolism rates.

The body can only metabolize a certain amount of alcohol every hour, and that amount varies depending on factors that include the liver size, body mass and enzymes in the human body. Some people can break down alcohol faster than others.

The new guidelines 

Experts who launched updated guidance on alcohol and health say people deserve to know the current facts about drinking alcohol — given new research that's emerged linking booze to cancer and heart issues since 2011.

Peter Butt, an associate professor at the College of Medicine at the University of Saskatchewan and co-chair of Canada's Guidance on Alcohol and Health, points out that Canada updated its guidance after other countries had done so, including Australia, France and the U.K. and U.S. He says alcohol has gotten a "free ride" when it comes to safety labelling for too long.

"We certainly have a problem, and it's hiding in plain sight. So this is why we want to shine light on it, provide information to Canadians so that they can make better informed decisions. They have a right to know," said Butt.

And the cancer risk related to alcohol can be higher depending on genetic factors.

"We're presenting this information based upon population health data, but if a person has a family history of breast cancer or indeed a personal history of breast or [gastrointestinal] cancer, they would be well advised to think very, very carefully about whether or not they want to engage with alcohol at all," Butt said.

Cancer risks understated for years

Elizabeth Holmes, senior manager of health policy at the Canadian Cancer Society, says drinking any kinds of alcohol hikes the risk for cancers, including those of the head, neck, breast, colorectal, esophageal, liver, stomach and pancreas.

"Drinking any type or amount of alcohol — so that's beer, wine and spirits — increases your risk for at least nine different types of cancer," said Holmes.

"It is the ethanol that is increasing your cancer risk."

The International Agency for Research on Cancer notes that some heavy drinkers never develop cancer while some moderate drinkers do, in part because the very genes that protect some people against alcoholism are now thought to make some humans more vulnerable to alcohol's carcinogenic effects.

Canada's alcohol-related deaths hit highs not seen in 20 years and kept rising during the COVID-19 pandemic, according to Statistics Canada, with a record 3,875 in 2021.

New U.S. research shows excessive alcohol use caused about 140,000 deaths per year in the United States between 2015 and 2019. About 60 per cent of those deaths were caused by chronic conditions attributed to alcohol, such as liver disease, cancer and heart disease, according to the New York Times.

The number of Canadian alcohol-related deaths is less than tobacco-related deaths — estimated at 48,000 per year, according to the Canada Gazette.

"The relative risk or the likelihood of tobacco increasing cancer risk, it's higher. Tobacco is linked with more cancer types, 16 compared to nine," said Holmes.

Cost of alcohol abuse cost Canada $16B in 2017

But the overall cost of alcohol abuse to Canadian society is the highest of any substance abuse. It cost Canada $4 billion in 2017 — or about $1,258 per person, according to Butt, citing the Canadian Substance Abuse Cost and Harms Report.

"When you look at the costs and harms of each particular substance in each jurisdiction. And what we find is that across the board, nationally and in every province except in the Maritimes, alcohol is number one," he said.

Of all the legally available and oft used psychoactive substances, alcohol and tobacco accounted for 63 per cent of the costs. Alcohol use alone cost Canada the most at $16.6 billion (36.2 per cent), about $12.3 billion (26.7 per cent) with other substances combined making up the remainder.

Butt says a lot of alcohol-related costs — such as trauma and heart disease — are not even part of the current tabulation.

"People are reflecting very deeply about this," said Butt.