One more reason why wine is good for you, and not just the red stuff

When it comes to health benefits, red wine tends to get most of the credit.

Cardiovascular benefits have been ascribed to alcohol itself (find a reasonably readable and full-text review here, courtesy of the Journal of the American College of Cardiology). But, of late (as in, say, the past decade), resveratrol has attracted the most attention; as a potent antioxidant, it truncates the chain of events involved in endothelial plaque formation (“hardening of the arteries”). Resveratrol is much more concentrated in red wine than in white. But resveratrol is a polyphenol, one of many. And polyphenols in general, and both red and white wine, have circulatory system benefits in lab studies we can ascribe to other causes.

For instance, NO, which is to say nitric oxide. Polyphenols encourage artery-lining cells to produce more NO. We know NO both as laughing gas and as a potent (if short-lived) vasodilator. NO tells the artery muscular to relax, which increases vessel diameter and lowers blood pressure. Arteries that no longer relax properly are a feature of many cardiovascular diseases and part of the cascade of interrelated faults that progressively damage both the heart and organs like the kidneys and eyes that suffer damage from blood pressure that’s consistently too high. NO also helps makes platelets less sticky with the effect of gently working against that damaging plaque formation.

Antioxidants, including polyphenols, increase NO levels indirectly by countering oxidative molecules that can rapidly destroy NO in the bloodstream. Polyphenols also stimulate NO production directly, and arteries benefit by learning to relax and suffering clogs less readily.

A paper just out in PLOSOne (always and ever open access) convincingly adds to evidence that caffeic acid, a polyphenol in which white wines are particularly rich, increases arterial lining NO production. The research team demonstrated that caffeic acid increases NO, but also that it improves arterial cell function and slows kidney disease damage in mice. Translating caffeic acid-dosed mice to white wine-dosed humans is still a leap we’ve not yet made, but it’s a likely one. Doses mice received were along the lines of what a moderately-drinking wine lover might ingest, and these sorts of mouse experiments have worked well to model human arterial disease in the past.

In short, there’s a good argument to be made that white wine is good for your heart. As good as red? That’s going a step too far, and not least of all because individual wines vary so much in their concentrations of resveratrol and caffeic acid and total polyphenols that we’d need to compare individual wines rather than try to stereotype by color. But the next time someone tries to talk you out of a glass of Chablis or riesling in favor of the red option for the sake of your health, don’t let them. You know more than they do.

In other news: three useful-if-not-groundbreaking reviews arose in recent days, on biotech uses for winery waste products, causes of and solutions for protein hazes, and polyphenols found in oak. Details are here.

And the winner for strangest wine experiment of the year goes to…

Research about the effect of wine on cancer is pretty common. Witness the slew of attention resveratrol has received for being, among other things — like the fountain of eternal youth or your key to firm skin with no injections — an anti-cancer agent. We also see plenty of epidemiological research: the population studies that say things like “moderate red wine drinkers are less likely to develop lung cancer.

How these studies work is easy to understand. Cancer-like cells grown in dishes are bathed in resveratrol-containing solutions and observed afterwards (in vitro = “in glass;” the dishes are more likely plastic these days, but the Romans didn’t have a word for plastic, gosh darn-it). Or whole organisms — mice, worms, humans — are fed resveratrol and observed afterwards (in vivo = “in the living”).

In the “I haven’t seen this before” file is an article released in preliminary form at Cancer Cell International a week or two ago that did things a bit differently. They bathed in vitro lung cancer cells in wine. Picture where your lungs are and where wine goes when you drink it. See the problem?

Wine per se never gets past your stomach. Just about everything we eat is broken down into component parts before being pulled out of the digestive tract and into the blood, with the indigestibles — things that can’t be broken down and transported into the blood, like the cellulose in plants — being left to exit the other end. Where and how a compound makes the move from digestion to blood depends on the compound. Polyphenols, the class of chemical which includes tannins and anthocyanins that give wine astringency and color, respectively, are mostly absorbed in the small intestines. Resveratrol** and alcohol are both fairly unusual in being absorbed directly across the mucous membranes in the mouth and pulled into the bloodstream, which explains why we get drunk so fast as well as why it makes sense to treat cancer cells directly with resveratrol.

Bathing cancer cells in wine is therefore a thing that will never, ever happen in your body. I suppose that cancer patients could be given red wine via an IV, putting it directly into the bloodstream where it would have direct access to cancer cells. Intuitively this seems like a bad idea, though I couldn’t say precisely why. I also don’t know if that’s what these scientists were getting at, or if this was just a “wonder what will happen if we try this” experiment.

It is interesting that very dilute red wine solutions — less than 1% — had specific anti-cancer effects. White wine was only effective at much higher doses – 2-5%. The effect (on specific signal transduction pathways; too complex to explain here) wasn’t the product just of resveratrol or alcohol; the authors haven’t yet figured out what specific wine components are responsible.

French hospitals include wine as part of patients’ regular diets, which I’ve always thought was a much more sensible attitude to nourishing recovery than the insipid and very non-alcoholic slop served up in most American hospitals. Sipping slowly on a glass of red is likely to do you more good than using it to tint your IV drip pink, though who knows? Maybe that is indeed the next thing.

 

**Because resveratrol is absorbed in the mouth, drinking wine is an excellent way to get it into your bloodstream: sipping gives it time to be absorbed. Swallowing a concentrated pill is a terrible mode of delivery. When it’s fast-tracked to the stomach — the pill bypasses those mouth membranes — very little resveratrol makes it out to where it can do any good. For a fantastic, if highly technical run-down of what we currently know about resveratrol, check out the micronutrient pages at the Linus Pauling Institute at Oregon State.