Many scientists have attributed the cardioprotective and life-extending effects of wine to resveratrol. For instance, the so-called “French paradox” purports to explain the fact that the French, despite eating lots of saturated fat, have low rates of heart disease, and this is allegedly because they drink red wine.
There are at least a couple of problems with this. For one, it’s my contention, and I know the facts will back me up, that there is no French paradox, for the simple reason that dietary saturated fat is not the cause of heart disease. I expect that most of my readers are down with that, but in case you’re skeptical, read this: Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease.
A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.
Since saturated fat doesn’t cause heart disease, neither the French nor anyone else needs an antidote in the form of wine or any other thing to fix it.
The other problem with the resveratrol in wine idea is that there’s so little of it in red wine, about 5 mg per standard glass. By contrast, experiments on animals have often used the human equivalent of 200 mg and more. This has often been stated that “you would need to drink x number of bottles a wine a day” to get the same dose. However, this too is misleading. Animal doses are not simply an extrapolation of human dose using a different weight; for instance, if a mouse gets 20 mg per kg of body weight, you can’t say a 75 kg man gets a human dose of 1500 mg. You need to account for metabolism, and in the case of a mouse you must divide by 12. (By 8 for a rat, and other animals have different values.) That means the human equivalent is a more manageable ~200 mg. But in any case, yes, you would need to drink a lot of red wine to get that amount of resveratrol.
Conclusion: the French paradox is malarkey.
There likely is some benefit of red wine because it contains polyphenols, which are substances that are plentiful in fruits, vegetables, tea, chocolate, and some other foods. Red wine is of course made from fruit, so that shouldn’t be surprising. Polyphenols have hormetic properties, turning on stress defense mechanisms like phase 2 enzymes and antioxidant genes such as superoxide dismutase. Polyphenols are in essence low-dose toxins.
Not long ago I wrote a post, Drinking alcohol is healthy – or is it? In that post I argued that most of the alleged benefits attributed to alcohol are really just an association, that cause and effect are far from proven. Drinking alcohol is correlated with IQ, that is, the higher your intelligence, the more likely you are to drink alcohol, and you are likely to drink more of it than less intelligent people. IQ itself has a strong correlation to health outcomes, the reasons for which are debated, but basically come down to a) higher IQ people take better care of themselves, or b) they have a smaller load of genetic mutations, lack of which produce both higher intelligence and better health. Or both, of course.
I noted that in order to prove cause and effect with regard to alcohol and health, you would need a randomized controlled trial in which people were randomized to an alcohol group and an abstainer group, and then see what health outcomes are like years down the road. To my knowledge, such a study has not been done, and seems unlikely to ever be done. So for now all we have is an association, and I’m skeptical that alcohol causes better health, however much I’d really like to believe it.
But is there any evidence, contra to what I’ve just laid out, that alcohol produces benefits to health? Yes, there is, in animals. Check out the following. Cardioprotective effects of red wine and vodka in a model of endothelial dysfunction.
Moderate alcohol consumption is largely believed to be cardioprotective, while red wine is hypothesized to offer benefit in part due to the proangiogenic and antioxidant properties of polyphenols. We investigated the cardiovascular effects of both red wine and vodka in a swine model of endothelial dysfunction.
Twenty-seven male Yorkshire swine fed a high-fat/cholesterol diet were divided into three groups and received either no alcohol (Control), red wine, or vodka. After 7 wk, myocardial perfusion was measured, and ventricular tissue was analyzed for microvascular reactivity and immunohistochemical studies.
There were no differences in myocardial perfusion, in arteriolar or capillary density, or in VEGF expression among groups. Total protein oxidation as well as expression of superoxide dismutase-1 and -2 and NADPH oxidase was decreased in both treatment groups compared to controls. Endothelium-dependent microvessel relaxation, however, was significantly improved only in the red wine-supplemented group.
Supplementation with both red wine and vodka decreased oxidative stress by several measures, implicating the effects of ethanol in reducing oxidative stress in the myocardium. However, it was only in the red wine-supplemented group that an improvement in microvessel function was observed. This suggests that a component of red wine, independent of ethanol, possibly a polyphenol such as resveratrol, may confer cardioprotection by normalizing endothelial dysfunction induced by an atherogenic diet.
The figure below shows that the amount of protein oxidation substantially and significantly decreased in the alcohol-fed animals. This means there was less oxidative stress, which is important to health and aging.
In this experiment, levels of antioxidant defense enzymes decreased – not what I was expecting – and the authors believe that this is because alcohol caused less oxidative stress, so higher levels of these enzymes were not needed.
So both red wine and vodka decreased oxidative stress, which probably means that alcohol had a hormetic effect, i.e. it is mildly toxic, and the animals here upregulated their defense mechanisms. However, only the red wine affected endothelial function for the better, and this has implications for protection against cardiovascular disease.
I think that this is decent evidence of alcohol’s health effects, although I would say more human trials are warranted. (I would be good scientist for getting grants, at least.)
Happy New Year, and Cheers!