Red wine has been heralded as a potential cure for cancer, a protector against heart disease, and helpful for maintaining a healthy weight. It's also been demonized as a carcinogen, linked to heart disease, and called a weight-gain culprit. But, the truth is probably hidden somewhere in between these extremes. We've tried to sort through the science behind both the benefits and drawbacks of regularly drinking red wine.
Let's start with the basics: Red wine's signature color comes from the pigment in the grape skins that are included in the fermenting process. Many of the health benefits attributed to the drink are related to resveratrol, which comes from the skins. It's an antioxidant, meaning it can prevent cell damage in some cases. And, you can even buy it in large doses as a supplement.
Some research suggests that, on its own, resveratrol can reduce LDL cholesterol (the "bad" cholesterol) and prevent blood clots. One of the first and most cited studies looking into this effect was published in 1993 in The Lancet. Here, researchers from UC Davis examined the degree to which resveratrol interacted with LDL in human blood. When LDL is normally oxidized, it can cause inflammation in the arteries, which can, in turn, lead to those arteries hardening. This makes heart attacks and strokes more likely. These researchers found that LDL oxidation could be kept at bay by adding resveratrol to the mix.
So, those results suggest that reservatrol in red wine can be helpful. But, it's hard to deny that by virtue of containing alcohol, wine is also unhealthy for many reasons. For instance, in a gigantic epidemiological study of almost 60,000 women with breast cancer and about 95,000 without, a 2002 study published in the British Journal of Cancer found a potential association between developing cancer and alcohol consumption. In their estimates, about 4% of cancer cases in developed countries could be attributed to drinking alcohol. Another study of over 105,000 women found similar results. This one, published in 2011 in JAMA, also suggested that consistently drinking a moderate amount of alcohol (including wine) could increase the risk for breast cancer.
Could these two forces of red wine — antioxidants and alcohol — be working against each other? And, does one outweigh the other? For heart disease, maybe. There are two strong, conflicting ideas in the literature about this. On the one hand, some scientists believe that red wine consumption could be responsible for the relatively low incidence of heart disease in France, despite a diet that is often high in saturated fats. This idea, termed the "French paradox," suggests that maybe we should be drinking more red wine and, specifically, that doctors should be encouraging non-drinkers to take up the habit for their health. However, other experts disagree, arguing that although there may be benefits to drinking red wine for those who already do so, "prescribing" it to others could do more harm than good.
One important consideration in these studies is always dosage: What do regular drinking habits actually look like in research? One small study published in 2010 tried to address this by looking at the effects of different amounts of red wine on heart rate variability in 12 subjects. It found potentially worrisome changes in heart rate after two glasses of red wine, but not one. So, its conclusion was to recommend limiting drinking to a single glass. Which, incidentally, is exactly the amount the American Heart Association recommends for women.
Right in the middle of all of this, we have a study from 2012 published in the journal Circulation Research. Here, 67 participants (all men, unfortunately) were given red wine, gin, or non-alcoholic red wine for four weeks. Throughout the study, each man had a turn with each beverage option. Those in the non-alcoholic red wine condition saw significant improvements in their blood pressure, but those in the regular wine condition did not. As The Atlantic so succinctly put it,"Pairing antioxidants with alcohol appears counterproductive."
However, it can also be difficult to know exactly how much of that precious resveratrol we'd get from one glass. Depending on the type of grapes, red wine could contain up to 14.3 mg of resveratrol per liter, which works out to about 172 micrograms in a single 120 mL glass, far lower than the investigated clinical doses.
So, if you're choosing between alcoholic beverages, red wine might be one of the healthiest choices you can make (depending on individual circumstances, of course). And, we'd certainly never tell you to give it up. But, if you're drinking wine specifically for the health benefits, you're probably doing it wrong: There are better sources of antioxidants out there that don't come with the potential downsides. Sorry, there goes your excuse.