You may just be kicking back with a good glass of Merlot to read my blog this evening, with the thought that you are doing your body a favour by choosing red wine over, say, a bottle of beer. The reported benefits of red wine have often been attributed to resveratrol. ‘Naturally’ (haha), the supplement industry has jumped all over this, and now markets resveratrol supplement. Resveratrol is touted as having a whole list of benefits… but is it really good for us?
Resveratrol is a natural phenol which is actually found not only in grapes, but also blueberries, raspberries, and peanuts. The highest readily available quantities per serving are found in grape juice or red wine. Resveratrol got some attention with the discovery that moderate consumption of red wine (1-2 glasses (5oz each) per day) may be associated with a decreased risk of heart disease, and since then, high doses of resveratrol (in supplement form) has been touted to carry a number of health benefits, including a decreased risk of cancer, improved diabetes control, neurological benefits, and even benefits to the skin.
While the evidence overall seems to suggest that red wine is associated with a decreased risk of cardiovascular disease, the reasons for this are not clear. Red wine increases levels of good cholesterol (HDL), but it’s not clear if it’s the resveratrol, or flavonoids in red wine, or something else that brings these benefits.
As for the remainder of the long list of supposed health benefits of resveratrol – these are far from being proven. A systematic review was undertaken a few years ago (which is the best way to look for evidence when there are only a smattering of studies otherwise), stating that the published evidence was not strong enough to recommend resveratrol beyond the dose that is found in dietary sources.
In terms of side effects, they found that there was no valid data on the the toxicity of chronic intake, and that the main known side effect of high doses of resveratrol is a laxative effect. Since then, a small randomized controlled clinical trial was recently published suggesting that resveratrol supplements had no benefit on any aspect of metabolic syndrome, and that high dose resveratrol actually had detrimental effects on cholesterol.
As for any supplement, in an industry which is very loosely regulated (and I use the term ‘regulated’ loosely at that), there is a huge amount of variation in the amount of resveratrol that one might actually get in a particular supplement. Purity varies as well, with the supplements containing other chemicals with unknown effects on human health.
Bottom Line: We find resveratrol in the same camp as most other natural remedies – there is insufficient data to suggest a benefit of taking high doses (supplements) to human health, and we don’t know about the safety of doing so.
As for getting resveratrol from red wine: It is not recommended to begin alcohol consumption for health reasons, as alcohol has many dangers and toxicities associated with it as well. For those who do enjoy a small amount of alcohol, it seems that red wine may be a good choice. See Canada’s Low Risk Alcohol Drinking Guidelines for more information on what is considered to be safe in terms of alcohol consumption.