Reality check: Is a daily glass of wine really good for your health?
There’s a memorable scene from the movie The Godfather, where Don Vito Corleone is seen sitting in his garden, nursing a glass of red wine and talking mafia strategy with his son and successor Michael.
“I like to drink wine more than I used to. Anyway, I’m drinking more,” the ailing don says wistfully.
“It’s good for you, pop,” Michael replies.
The Godfather may have been a fictional tale, but Michael Corleone’s stance on wine is common in the real world too. For decades now, it’s been a widely held assumption that a glass of wine a day is good for your health.
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It’s a reassuring thought and one that wine drinkers have taken great solace in, comfortably complacent in the knowledge that theirs is a constructive vice, and perhaps not even a vice at all.
But does this long-held belief stand up to close scrutiny of the scientific literature?
Last year, news outlets from the U.S. to the U.K. to as far away as India gleefully reported that having a glass or two of wine with dinner was found to be good for your health and mental well-being, citing a Finnish study published in the journal Alcohol and Alcoholism.
However, a cursory look at the Finnish paper reveals a crucial caveat conveniently ignored in news reports: “Consumption of wine with meals was associated with high socioeconomic status and high subjective well-being.”
This line hints that wine drinkers tend to belong to well-off demographics, and this is what may explain their good health and subjective well-being – not so much the wine.
Indeed, back in 2006, Danish researchers found that people who plopped a bottle of wine in their shopping carts were also more likely to pick up fresh produce and other healthy ingredients for their fridge than beer drinkers, who tended to load up on frozen meals and high-sugar snacks.
There’s a reason why “correlation does not infer causation” is such a widely recited mantra among scientists.
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Tim Stockwell, director of the Centre for Addictions Research of BC, says moderate wine drinkers often do enjoy an edge in the health stakes – but it has nothing to do with their consumption of wine per se.
“We know that moderate wine drinkers tend to be wealthier, and wealthier people have better health. They exercise more, they tend to have a healthier weight, they’re more likely to cut the fat off their meat, they’re more likely to jog,” Stockwell says.
“Wealthier people also have more steady drinking patterns, they don’t have binge-drinking patterns as much… so I think that has led to this idea that wine drinkers sometimes appear to be healthier than beer or spirit drinkers, and abstainers.”
Other experts agree that linking good health to wine consumption is simplistic and even inaccurate.
“We’re always looking for the magic bullet, we’re always looking for a specific ingredient when, in fact, everything we look at seems to suggest that it’s really all about a pattern of eating and a lifestyle,” Rena Mendelson, a nutrition professor at Ryerson University, told Global News.
“They’re looking for a single answer to their questions. This isn’t the solution.”
Perhaps the most enduring argument in favour of a daily glass of wine is that the fermented grape beverage is good for that most critical of organs, the heart.
But it’s not that simple. Yes, moderate drinking can reduce the risk of heart attack, but it also increases the risk of atrial fibrillation, or irregular heartbeat, which in the long term can increase the risk of heart failure, according to a 2016 study published in the Journal of the American Heart Association.
Sound confusing? Well, the relationship between alcohol and heart health is a complex one.
“I’m constantly trying to remind people that there are various forms of heart disease and not all are related to heart attack,” said lead researcher Gregory Marcus of the University of California, San Francisco, in a news release.
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A comprehensive new review by Stockwell and his colleagues found major flaws in studies linking alcohol to improved heart health. For the study, published in the Journal of Studies on Alcohol and Drugs, the researchers conducted a meta-analysis of 45 different studies that examined the link between alcohol consumption and coronary heart disease.
They found that many of the supposed “abstainers” in those studies were actually former drinkers who had to abstain for health reasons, meaning they weren’t a fair representation of people who don’t drink.
“As people get sick, they stop drinking, and three-quarters of the studies we examined had that fundamental error where they just count someone as an abstainer if they haven’t drunk in the last year,” Stockwell says.
It’s known as the “sick quitter effect” in alcohol research circles, and effectively creates the illusion that moderate drinkers enjoy a health advantage over abstainers.
This leads to studies ending up with results claiming that people who don’t drink are worse off than those who drink moderately, when in fact the abstainers in those studies might have had pre-existing health problems owing to their past drinking or other issues.
What’s more, research on alcohol and health tends to be observational rather than experimental, meaning researchers don’t have control over external variables that can mar results. This has resulted in a number of funky findings over the years, with moderate alcohol use being dubiously linked to reduced risk of hearing loss, hip fractures, liver cirrhosis, psychiatric disorders, asthma, Type 2 diabetes and even death itself, results that Stockwell dubs “impossible biologically.”
This means a significant chunk of the scientific literature linking alcohol to health benefits is tainted by the inherent flaws of observational studies as well as biasing phenomena such as the sick quitter effect and self-report bias (people misreporting their alcohol consumption).
One might protest that these studies, including Stockwell’s meta-analysis, looked at alcohol consumption in general and not wine specifically – but that’s a moot point.
“Whenever I’ve looked at the literature, if there are health benefits, they apply equally to beer, wine and spirits. There’s nothing special about wine,” he says. “The epidemiological evidence doesn’t really present a case for it being especially about wine… if there are some non-alcohol ingredients in wine, people can get them from red grapes or whatever.”
Indeed a 2012 study published in the journal Circulation Research found that daily consumption of red wine is healthy – if the wine is de-alcoholized.
In other words, wine may contain grapes or anti-oxidants, but alcohol is still alcohol. Your body doesn’t know whether the ethanol in its system came from a $50 Chianti or an $11 six-pack of Lucky Lager.
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It gets worse. A major new study found that drinking a small glass of wine a day increases women’s risk of developing post-menopausal breast cancer by 9 per cent. Enjoying five or more glasses of white wine a week might make women nearly 50 per cent more likely to develop rosacea, according to another recent study.
The list goes on. But these findings throw up one compelling question: How did we come to believe in wine’s health benefits in the first place?
It all started with a CBS 60 Minutes episode that aired back in 1991. The program featured what Stockwell labels “some alcohol industry/wine industry-friendly academics” discussing the so-called French Paradox, which ponders why French people have lower levels of heart disease than Americans despite their high-fat diet.
After interviewing the academics, CBS correspondent Morley Safer concludes the episode by taking a seat at a table, a glass of red wine in front of him, and assuring viewers that the link between red wine and reduced risk of heart disease is “all but confirmed.”
“The answer to the riddle, the explanation of the paradox, may lie in this inviting glass.”
Safer’s report prompted a spike in demand for red wine in the U.S., while the French Paradox theory still remains to be proven, CBS admitted 25 years later.
Similar threads of misinformation have been woven in the decades since that now-iconic episode, with the alcoholic beverage industry using various tricks to get their preferred message out.
Common methods include “funding scientists who find results that they approve of, and funding groups who review studies and put out communications critiquing studies that are unfriendly to the industry,” Stockwell says.
“There’s quite a bit of subtle distortion of what kind of science gets done and how it’s communicated.”
Stockwell urges people to pay close attention to where studies about alcohol come from, and who they’re funded by.
“I suggest they trust more results from independent researchers that have done systematic, comprehensive reviews of the literature, rather than one study plucked out and promoted by some nameless communications agency and put out in the media,” he advises.
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However, there is an encouraging common thread that runs through the research linking wine to unsavoury health outcomes: drinking moderately as part of an all-round healthy lifestyle is unlikely to harm you.
The numerous studies linking alcohol to increased risk of breast cancer, heart disease and other ailments all state that exercise and a nutritious diet significantly mitigate the negative health effects of alcohol.
But if you think drinking a glass of wine a day is going to protect against disease, boost your health or expand your lifespan, you’d best think again.
– With a file from Carmen Chai
© 2017 Global News, a division of Corus Entertainment Inc.