Red Wine and Heart Disease | The Body of Evidence

Red Wine and Heart Disease

There's always a study coming out claiming that red wine will reduce inflammation, lower blood pressure, improve cholesterol or some other such thing. But is it actually good for your heart? I deal with that issue in my Gazette article.



Whenever I meet someone for the first time and they find out I’m a cardiologist, they apparently feel compelled by some higher power to make some sort of comment about red wine being good for your heart. Once somebody extolled the virtues of red wine being cardio-protective while smoking a cigarette in front of me. I was tempted to point out the irony, but I politely chewed on my straw instead. So I was not totally surprised last week when several people informed me that a new study has proven that red wine is good for your heart.

The study in question randomized 224 obese teetotaling diabetics (if you are not an obese teetotaling diabetic, this study may not apply to you) to one of three treatments: mineral water, white wine or red wine. It called on people to drink 150 ml of their assigned beverage every day. Now 150 ml of wine is about 10 tablespoons. That is in fact a “standard” serving of wine. If you drink more than that, you are not a “moderate” drinker, as far as scientists are concerned.

But back to the study. After two years, all three groups were healthier. That was largely due to the fact that all three groups were also told to eat a Mediterranean diet. But when the researchers compared the groups, they found that the red wine group had a higher level of HDL cholesterol (the good cholesterol) compared to the water drinkers. Since a higher HDL is good for your heart, ipso facto, red wine must be good for your heart.

This however is a dangerous interpretation to make, because HDL is what we call a surrogate endpoint, essentially a stand in for something that we actually care about it. We actually care about preventing heart attacks, but we use HDL as a surrogate. This is done a lot in medicine, and it burns us almost every time.

Just because something improves your cholesterol, doesn’t mean it’s necessarily good for your heart. Niacin (vitamin B3) also raises your good cholesterol, but doesn’t lower your risk of heart attack. Pfizer tried to develop a medication called torcetrapib, which raised your HDL. It didn’t prevent heart attacks either. Actually, it increased your risk of heart attack by 25 per cent.

Yes, surrogate endpoints can be deceptive things. In this study, red wine raised good cholesterol by 0.05 mmol/L. That is so trivial an increase, that it barely justifies acknowledging it. It also worth noting that in this study, red wine did not affect blood pressure, LDL cholesterol (bad cholesterol), hemoglobin A1C (a measure of diabetes control) or the patient’s weight. All of these things are much more important in determining your risk of heart attack than HDL cholesterol.

In the end, the only thing that matters is whether red wine prevents heart attacks and lowers your risk of dying.

It did neither of these things in this study. Buried deep in an online appendix (and not mentioned in the main paper, I might add), data show that no one in the study died during the two year follow-up and that there were very few heart attacks in any of the groups. I remind you that they were all eating a Mediterranean diet.

Many people will use this study as a justification to drink or to choose red wine over white. In truth, it doesn’t really matter what type of alcohol you drink and there is not much harm as long as you drink in moderation (see above for what moderation means), and avoid driving after you’ve been drinking.

And for those of you who remain convinced that red wine is good for your heart: if you meet me at a dinner party, I’ll be politely chewing on my straw.