Of all the health-related questions that end up in the Wine Spectator electronic mailbag, some get asked with a you-can-set-your-watch-by-it type of regularity. We've answered them before, and we'll answer them again, but I thought I'd address these topics here with the help of Dr. Andrew Waterhouse, professor of enology at the University of California at Davis, to weigh in on the three most enduring topics.
Health Myth No. 1: Wine contains a lot of sugar
It's easy to see where this theory may have started. Grapes have sugar. Wine is made from grapes. Therefore, all wine has sugar? Not so. "If a wine is considered dry, the amount of sugar consumed is quite small," said Waterhouse. The fermentation process for dry wines eliminates almost all the sugar and converts it to alcohol.
Let's go to the data: The USDA Nutrition Database lists the amount of sugar in a 5-ounce serving of red table wine at just 0.91 grams. Not to pick on orange juice, but an average 8-ounce serving of the stuff contains 20.9 grams of sugar, so 5 ounces of orange juice contains nearly 14 times as much sugar as the same amount of dry red wine.
However, if you're a diabetic looking to understand how alcohol affects your blood sugar levels, that's an entirely different question complicated by the rest of your diet, activity levels and insulin therapy. Even medical practitioners have divided outlooks here: Waterhouse pointed out that in the United States, the convention has been to discourage diabetic patients from drinking, but not so in the United Kingdom. (Recent research suggests that moderate alcohol consumption, which can temporarily lower blood sugar levels, is associated with a lower risk of developing diabetes.) If you're concerned about how wine affects your blood sugar levels, you should talk to your doctor to find the best approach for you.
Health Myth No. 2: Sulfites in wine cause headaches
Headaches caused by wine consumption are a real problem for some folks. Sulfites—which can occur naturally in wine and are also often added as a preservative to wine and foods such as dried fruits—incorrectly often bear the brunt of the blame. "There is no medical evidence that sulfites cause headaches," said Waterhouse.
Only a very small percentage of the population has a true allergic reaction to sulfites, and that allergic reaction ranges from rashes to breathing problems—not headaches. Wine-triggered headache research has identified many possible culprits other than sulfites, including histamines, daily stress, any number of compounds in wine or the alcohol itself.
But as Waterhouse noted, "Everyone is very ready to draw conclusions [about sulfites and headaches] from their own experience." For the true believers in a link between the two, he concedes no study has been done to address this query. Don't hold your breath, he said: "As far as we know yet, no one has died yet from 'sulfite headaches,' so the NIH [National Institutes of Health] is not rushing to study this."
Health Myth No. 3: We know what component of wine promotes health
Studies on the correlation between the consumption of wine (or a substance in wine) and disease X or disease Y seem to come out every other week (See this round-up for examples.) As such, we get many questions that ask, "Which wine is the healthiest for my particular condition?"
But Waterhouse said, "These studies can't prove that a particular substance in a wine is the causal factor." The reason is that "the best data is epidemiological data"—from studying large populations of individuals over time and determining patterns of disease. You can imagine the number of variables involved with this type of study: how much a person exercises, what they eat, what else they drink, and how all those factors interact. So pinpointing whether health benefits are due to alcoholic beverages in general or wine in particular, much less a particular substance in wine, is a challenge.
So it's something of a moot point to try to determine what type of wine is "healthier" because it's rich in substance A or B. The amount of any compound in an individual wine can vary not only by grape or region, but by growing-season conditions, viticultural techniques or winemaking practices. And different compounds could have different benefits.
One relationship that the data shows? "Most experts are willing to say that non-drinking is a risk factor for dying from cardiovascular disease," Waterhouse said. "The effect is quite substantial. … If you look at 10,000 people, a mix of [moderate] drinkers and non-drinkers, half as many people will die in the drinking group. That is really clear."
Are there any questions about health that you have for us? Or have you run into any wine-related health myths?