A glass of wine a day keeps the doctor away – or does it? From the French to the Sardinians, there are cultures where people tend to drink wine every day known low (opens in new tab) rates of heart disease and lead longer lives (opens in new tab), on average, than Americans do. But does drinking wine really help you live longer?
The belief that a daily glass of wine was responsible for the health and longevity of people living in wine-oriented food cultures dates back to 1992 paper (opens in new tab) who called this phenomenon the “French Paradox”, pointing to wine as an explanation. Today, however, our understanding of wine and its effects on health is more nuanced. There is some evidence that drinking wine protects against certain health conditions, but evidence that it leads to longer life is scarce, said Adrian Baranczuk, professor of cardiology at Queen’s University School of Medicine in Ontario. “Alcohol studies are limited by their design,” he said.
For starters, much of the research on red wine and mortality does not focus on the wine itself. Rather, the study examined the health effects of polyphenols, species antioxidant in wine. These chemicals protect cells from damage caused by unstable molecules called free radicals, which are linked to heart disease and crab risk and have been suggested as one of the potential reasons for the purported positive health effects of wine.
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When an international team of researchers pooled the results of 22 studies and analyzed them as a whole, they found that people who consumed 800 milligrams of flavonoids — a type of polyphenol found in wine as well as most fruits and vegetables — per day had a 24% lower risk of death within the study period compared to those who did not consume flavonoids. Their 2017 results, published in American Journal of Epidemiology (opens in new tab), found that this difference decreased by 6% for every 100 milligrams reduction in flavonoid consumption. (For example, people who consumed just 700 milligrams had an 18 percent lower risk of death.)
The problem is, 800 milligrams is a lot of flavonoids. “You’d have to drink gallons and gallons of wine to benefit,” said Bill Klein, associate director of the National Cancer Institute’s (NCI) Behavioral Research Program. Klein studies behavioral risk factors for cancer and has published articles on the health effects of alcohol. In a study published in 2001 Journal of Nutrition (opens in new tab), participants who consumed 750 milliliters of wine (about four 6-ounce glasses) ingested only about 24 milligrams of dietary flavonoids. Based on this result, to get 800 milligrams per day, you would need to drink 133 glasses of wine. And there are other, potentially healthier sources of polyphenols: The Journal of Nutrition study found that participants absorbed more polyphenols when they ate onion.
There is some evidence that drinking moderate amounts of wine is heart-healthy, Baranczuk said. About two cups, five days a week for men or one cup, five days a week for women – guidelines (opens in new tab) recommended by the American Heart Association—appears to be rising good cholesterolreduce the risk of blood clots, help prevent them artery damage caused by bad cholesterol and improve the function of the layer of cells that line blood vessels compared to people who don’t drink at all, he said.
Part of this cardiovascular health benefit may be due to the effects of polyphenols, he wrote in a 2017 review on the topic published in the journal Circulation (opens in new tab). But those benefits are more likely due to ethanol, which is present in all alcoholic beverages, Baranchuk said. An analysis pooling the results of 42 studies found that 30 milligrams of ethanol per day (approx two drinks (opens in new tab)) increases HDL cholesterol (the good kind) and apolipoprotein AI, a major protein found in HDL. However, “all of these benefits are first attenuated and then reversed if you drink above the recommended guidelines,” Baranchuk said.
Is a glass of wine a day harmful?
The problem is that heart disease isn’t the only factor in health and longevity. And the alcohol in wine can negate the benefit of polyphenols. “Unfortunately, there’s not a lot of evidence that alcohol provides a protective effect,” Klein said. “There is much more evidence that this is a risk factor.”
While the evidence that wine reduces mortality over time is thin, it is there a lot strong evidence (opens in new tab) connection any amount of alcohol to breast cancer, liver crab, the prostate cancer and cirrhosis, among other diseases. That may be because alcohol changes the way the body processes estrogen, causing levels of that hormone to rise, Klein said. Another potential explanation: Acetaldehyde, a byproduct of the breakdown of alcohol in the body, has been shown to cause DNA damage.
After all, if you’re not in the habit of drinking a glass of wine a day, or if you just prefer beer, there’s no reason to adopt the habit for your heart’s health. Try yoga or meditation instead, Baranchuk said, as “they have a way more solid (opens in new tab) evidence (opens in new tab) than what alcohol has.”
If you already enjoy a glass of wine most evenings and aren’t sure about the effects of your habit on your health, check with your doctor—especially if you have any underlying health problems. But for most people who drink in moderation, there’s no need to stop, Baranchuk said. “We balance the pros and cons of the risks all the time,” he said. “For example, let’s say your office is 25 minutes from your home. Driving those 25 minutes increases mortality by 0.005%. Would you say, ‘I’m not going to work anymore, even though I love my job and it brings in the income?’ You say, “I accept that risk.”
Originally published on Live Science.