Vox published an article by Julia Belluz last week entitled “The Truth About Red Wine’s Health Benefits,” and while Belluz did a credible job with the topic, the topic was critically flawed from the outset. Titling an article “The truth about X” is gutsy. First, you’re saying that there is a truth about X, just one of them in fact. Second, you’re saying that you know what that truth is. Or that your sources know it. Getting anywhere with the wine-and-health story means trusting that the scientific studies and researchers she consulted could provide “the truth of the matter.” They can’t.
There are two major problems with scientific studies on “the truth” about wine and health. The first is about definitions. The second is about measurements. Both are about how science works and the kinds of questions scientists ask.
Definitions are important because where you start ultimately determines where you can end up. The scientific method depends on asking questions and then answering them carefully and systematically. As even non-scientists know from personal experience, the kinds of questions you ask are crucial for influencing the kind of answers you get.
“Hey, honey, would it be possible for you to take the baby sometime this week?”
“Hey, honey, will it be easier for you to take the baby Wednesday or Thursday? I need to schedule a meeting.”
When an article this year on alcoholic beverage labeling asked whether labeling has “improved,” they had to start out with some definition of what “improvement” meant, and the idea that alcoholic beverages are drugs about which the consumer needs to be warned in the first place. This idea that wine is a drug shows up in social research, and it shows up in wine health research. It’s no wonder. The United States regulates wine and other alcoholic beverages through the Alcohol and Tobacco Tax and Trade Bureau, the TTB, not the Food and Drug Administration (FDA). To the US government, wine and beer are more like guns and cigarettes than like food. That affects what kind of funding researchers can obtain for alcohol-related research.
Research often starts with this idea of wine as a drug and ask: when is wine a useful drug? When is wine a harmful drug? If we start off thinking of wine as food instead of as medicine, that approach doesn’t really make sense.
Belluz quotes a Harvard physician-scientist to the effect that wine is only useful for heart disease and diabetes. When drugs go up for approval with the Food and Drug Administration, they’re approved to treat specific conditions under limited circumstances. You may have heard about “off-label” drug use, when a physician prescribes a drug for a condition it hasn’t been approved to treat. In our Western medical system, drugs treat conditions, not people.
This is a silly way to think about drugs, but it’s an especially silly way to think about food. When you ingest something, you may be thinking about its effect on your breathing, or a skin rash, or your ability to think clearly, but in most cases what you care about at the end of the day is how your body functions as a whole. We’ve devised piles of drugs with nasty side-effects, in part because we fix disease rather than promoting health. Are some of these drugs wonderful? Do fixing disease and promoting health sometimes overlap? Of course. But the way we think about how drugs work and what they’re good for means that the focus is on fixing one broken thing. When research imagines wine as a drug, it thinks about its ability to fix one broken thing: heart disease, or diabetes, or colon cancer. If wine is a food, not a drug, the questions change.
Then there’s the measurement problem. As Belluz explains, since researchers can’t ask people to follow a proscribed drinking regimen for weeks or months, they have to make do either with very short-term studies or with observational studies of people who are already drinking or not drinking of their own volition. Something she doesn’t mention is that studies often also employ surveys in which people are asked to report their past drinking behaviors. As you might imagine, that strategy comes with it’s own set of issues. But in all of these situations, even for the experimental studies, scientists have to decide at the outset of the experiment what the relevant variables are and how to divide them into categories.
Alcohol-health research has tended to focus on how much people are drinking, maybe with some sort of questionnaire asking people to report how many glasses of wine or bottles of beer they drink on an average week. Those sorts of questions assume that all alcohol consumption is the same. What if it’s not? Medicine has recognized that binge drinking is a problem, and so we see recommendations that women consume no more than one drink per day on average, or two for men. According to the National Institute on Alcohol Abuse and Alcoholism, “low-risk drinking” means having no more than three drinks for women, four for men, in one sitting. Current science classifies the “risk” of alcohol as the risk of low, moderate, or heavy consumption. No doubt; amount is clearly important.
But what if how much you drink isn’t the only important consideration? Research is only just beginning to pay attention to the difference in long-term health effects between imbibing with a meal and having a habitual after-work drink or two in-between eating. Likewise, when studies ask whether red wine is better than white wine, they’re assuming that those are the most relevant categories. They also assume that, for health purposes, all red wines are more or less the same and distinctly different from all white wines, which again can be treated as more or less the same. What if the way the grapes were grown mattered? Or the age of the wine? Or the kind of food you chose to accompany it? Or the mood you were in while you were drinking? As its been designed, research simply wouldn’t be able to capture that information.
In other words, the best way to understand the roles wine plays in health and disease may not be the kinds of questions science is asking and the kinds of measurements science is making. The seeming contradictions among research findings suggests that they’re not. When research findings conflict, one or both of two things might be happening. Either scientists are making experimental mistakes, or experiments aren’t paying attention to the right factors, or both. An experiment can only control for and measure so many things. One or more of the factors being ignored may in fact be important to the outcomes of the experiment. But if it’s not being measured, that connection can’t be made. Instead, the effect of mystery factor X may be lumped into “unexplained variation:” results that the scientist can’t explain using the data she chose to collect. The seemingly endless parade of studies telling us first one thing and then the opposite about wine and health suggest that maybe scientists haven’t yet hit on measuring the important variables to measure.
And then there’s a third problem, not about the truth of wine health research, but about what it’s good for. What if research conclusively demonstrated that weekly consumption of three to five glasses of wine with food and up to two additional glasses without food decreased the risk of heart attacks for women over forty of European descent, but that any more than three glasses of wine per week increased the risk of colon cancer in European women over forty who have a family history of colon cancer. I’m making up the details, but these really are the kinds of conclusions epidemiological research on wine and health produce.
If you were a Polish-Irish woman over forty, what would you do? Would you keep those guidelines in mind, along with all of the other guidelines about diet and exercise and other lifestyle behaviors related to all of the other chronic diseases and cancers you might get? We know that too much stress isn’t good for mental or physical health, either, and managing all of those guidelines sure sounds stressful. Moreover, most cancers are random as far as we understand them; you may be able to increase or decrease your risk, but you’ll also certainly change the kind of lifestyle you choose to have. I hope that, instead, you would you try to eat moderately, exercise, and drink moderately – unless you had a specific reason to abstain, like a family history of alcoholism or religious belief or sheer personal preference? Or maybe you would choose to live an immoderate life because that’s your thing; moderation and prioritizing quantity of life isn’t for everyone. As Belluz notes, the bottom line on which all of the research tends to converge is that moderate drinking is okay and maybe even good for most people.
Wine is usually about reducing stress, not making more of it, about enjoying good food and good company. The Harvard physician-scientist Belluz quotes recommended (in Belluz’s words) “that exercise might well be a better way to get heart benefits compared with moderate drinking.” Sure. But since when has that been the point?