We’re at a nice restaurant, and the couple sitting at the table next to ours is clearly enjoying their dinner, but especially their wine. They’ve spent at least 10 minutes poring over the wine list, and when the waitress brings over the bottle of Williams-Selyem 2014 Pinot Noir to their table, their eyes light up. They savor every aspect, commenting on the hints of dark cherry, nutmeg, and faded rose—the power, the finish, the polish and grace of the wine.
We do lots of things in life mainly for fun and pleasure, and drinking wine is one of them. But of course scientists and health researchers study most of our lifestyle choices, and in the last few years they’ve come to some new conclusions about the health effects of alcohol, including wine. I’m going to focus here on the effects of wine on your risk of cancer. (Spoiler alert: if you want to enjoy your wine and not think about potentially adverse effects other than a possible hangover, stop reading now.)
For at least 2000 years, wine enjoyed in moderation has been thought to be beneficial for health. The Talmud says, “Wine is at the head of all medicines; where wine is lacking, drugs are necessary.” And indeed modern studies back up the claim that alcohol in moderation does lower the risk of coronary heart disease somewhat. What’s moderate drinking? For an average-sized man one or two, five-ounce glasses of wine daily and for an average sized woman one glass (because women generally metabolize alcohol more slowly than men, generally weigh less, and have a lower percent of water in their bodies). Alcohol raises the good HDL cholesterol and may have anti-inflammatory effects.
And you’d think that wine would lower the risk of cancer, too. After all, red wine is packed with resveratrol and other polyphenols, which mostly come from the grape seeds and skin. Polyphenols have antioxidant properties, and resveratrol in cell line studies interferes with several stages of carcinogenesis. One glass of red wine has the antioxidant activity of seven glasses of orange juice and 20 glasses of apple juice (In case you’re wondering, white wine has only 1/12 the antioxidant activity of red wine).
But here’s the catch: the resveratrol in wine is poorly absorbed from the human stomach. It’s estimated that an average sized person would need to drink 1,000 liters of red wine daily (!) to absorb enough resveratrol to achieve the cancer health benefits seen in studies in mice. And that much wine would probably produce a pretty bad hangover.
The alcohol that is readily absorbed from your stomach is unfortunately converted in your body to acetaldehyde, and it’s this aldehyde compound that seems to be carcinogenic, binding to DNA and proteins in cells, modifying them. This also causes oxidative stress in cells. The International Association for Research on Cancer (IARC) now lists alcohol as a group 1 carcinogen, meaning it’s known to cause cancer in humans. It seems that the cancer-causing effects of the alcohol outweigh any putative cancer protective effects of resveratrol and other polyphenols in wine. Small studies using resveratrol concentrates to treat cancer have not shown beneficial effect against prostate cancer, and one study showed it could cause kidney damage in patients with multiple myeloma. There are no studies showing a benefit for resveratrol concentrates to prevent cancer.
A recent overview analysis in the Journal of Clinical Oncology of modern studies of alcohol and cancer concluded that drinking alcohol causes 5 percent of all cancers, unfortunately. This includes several common types of cancers such as breast cancer, colon cancer, liver cancer, esophageal cancer, and cancers of the head and neck area. Drinking wine was no safer than drinking beer or hard alcohol either. The effect of alcohol on cancer risk was seen mostly in moderate and heavy drinkers, but even light drinkers had an increased risk of breast cancer and esophageal cancer. For those who stopped drinking completely, the excess risk of developing some cancers reverted to normal, but only slowly over the subsequent 20 years.
So, should you open that bottle of Pinot tonight? Those who drink wine moderately are at no higher risk of dying (and may be at slightly lower risk because of heart-healthy effects) than teetotalers. But if you’re particularly concerned about reducing your chance of developing cancer, I recommend limiting your wine (and other alcohol) intake. Like choosing between a Pinot and a Cabernet, it’s a personal choice, and one where you should weigh the pros and cons.
Peter Brett, M.D., is a board-certified medical oncologist at Sutter Medical Group of the Redwoods in Santa Rosa, and affiliated with the Sutter Santa Rosa Regional Hospital. He’s been practicing oncology for more than 25 years. For more information, go to sutterpacific.org, or call (707) 521-7750.
