Log In / Join Now

Hand Me the Châteauneuf Sunblock?

A study finds grape polyphenols prevent sunburn damage to cells, but only in the lab

Margaret Raber
Posted: August 9, 2011

Sunburns, like punishing humidity and hungry mosquitoes, are an unfortunate byproduct of summer. What's more, skin damage can lead to more serious problems, like skin cancer. Compounds in wine may offer some relief to sizzled cells, however, according to an experimental study recently published by the Journal of Agriculture and Food Chemistry. But experts tell Wine Spectator that doesn't mean a wine dip will protect your skin.

For the study, Barcelona-based researchers observed a variety of polyphenols from wine grapes and their protective effects on human skin cells exposed to UVA and UVB radiation. Under a laboratory microscope, the grape compounds reduced the production of UV-induced Reactive Oxygen Species (ROS), which are responsible for sun damage to cells. Less cell damage means reduced risk of skin cancer, sunburn and premature aging.

ROS is always present in our bodies as a byproduct of the way our cells break down food molecules. At normal levels, ROS plays an important role in the health of our cells. At high rates, however, ROS causes oxidative damage to DNA and lipids and can result in cell death.

When you're relaxing in the sunshine, the rays hitting your skin are generating ROS, leading to DNA damage of cells. Sadly, that ‘healthy’ summer tan is merely a sign that your skin has already undergone damage and is darkening as a defense against further attack. UV-inflicted DNA damage is a major cause of skin cancer. The World Health Organization and the U.S. Department of Health and Human Services have named UV rays as proven carcinogens.

The Spanish scientists classified the polyphenols found in wine grapes based on molecular make up. That way, the researchers could detect exactly how effective certain grape compounds are at protecting human skin. In general, the results were positive, with ROS reduction of about 50 to 60 percent depending on the structure of the polyphenol.

What the study did not offer, however, was what those results mean for the wine-drinking or grape-eating public. “Thinking of plants as chemical factories and the antioxidants they produce as drugs, then the dose is important," said Dr. David McDaniel, assistant professor of dermatology at Eastern Virginia Medical School and an antioxidant researcher. "The article does not answer how much concentration of the best polyphenols in the grape extract would be in some specified volume of red wine.”

So, as good as it sounds to swap that sunscreen for a bottle of rosé, it remains unknown how much you need to drink to get any protective benefits for your skin. ”I don’t think anyone really knows what amount of these [polyphenols] actually reach the skin from oral consumption," said McDaniel.

What about taking a wine dip before hitting the beach? Not recommended. A 2008 study entitled “Sun Protection by Red Wine?” published in the Journal of the German Society of Dermatology, found application of wine to the skin⎯even a polyphenol-rich Château La Nerthe Chateaunuef-du-Pape 1999 ⎯offered no protective benefits from UVB radiation. It did, however, score a solid 90 points from Wine Spectator.

While Dr. McDaniel admitted the Spanish study is of primary use to researchers and drug or cosmetics companies, he promotes the skin benefits of all kinds of perplexingly named dietary antioxidants, from proanthocyanidins in grapes and catechins in tea to lycopene in tomatoes. His recommendation? “You might want to think about having a nice cup of tea every day, perhaps a bit of coffee, some good wine, and some nice tomatoes with virgin olive oil—and still use your SPF."

Would you like to comment? Want to join or start a discussion?

Become a WineSpectator.com member and you can!
To protect the quality of our conversations, only members may submit comments. Member benefits include access to more than 315,000 reviews in our Wine Ratings Search; a first look at ratings in our Insider, Advance and Tasting Highlights; Value Wines; the Personal Wine List/My Cellar tool, hundreds of wine-friendly recipes and more.

WineRatings+ app: Download now for 340,000+ ratings.