A lot of people seem to think that they’re allergic to wine. Most probably aren’t. Our current best evidence on sulfites says that only people with severe asthma have any real cause to worry and, given the presence of sulfites in many other common foods – most dried fruit, many cured meats, salad bars – it’s something they surely know before ever meeting their first glass of wine. I’m one of a subset of people who react dramatically to biogenic amines, molecules produced by some yeast and bacteria that mimic human hormones and cause me to go hot and red in the face and sprout a bad headache after only a few sips of an affected wine (embarrassing when people think I’m tipsy after half a glass). Another subset (including many Asian people) honest-to-goodness doesn’t metabolize alcohol well, thanks to a genetically encoded difference in an important enzyme, and turns hot, red, and otherwise uncomfortable in response to any alcohol. None of these are actually allergies.
So, do wine allergies actually exist? Yes.
Back in 2012, a group of German epidemiologists sent out a survey asking random adult residents of Mainz whether they had experienced symptoms of “wine intolerance.” 7.2% of people who responded to the survey attested to some form of wine intolerance. I wrote about some problems with the study on Palate Press: the possibility that respondents might have confused “intolerance” symptoms with a hangover, the likelihood that the survey overestimated people with problems because they’re the most likely to respond (and three-quarters of people sent the survey didn’t respond), the power of suggestion. Still, the study begs the question. How many people really are allergic to wine?
The same group has followed up with more research aimed at answering that question. Of the 68 people marked as “wine intolerant” by the original survey, they convinced 19 to sit down, along with ten non-intolerant controls (mostly women), for a battery of allergy testing. In addition to the familiar skin prick test – inject a bit of potential allergen X under your skin to see if you come up red and swollen – they also used several blood tests all looking for the release of inflammatory molecules in response to wine and grape products, including riesling, pinot gris, pinot noir, and dornfelder wine. All of these tests measure reactions to grape proteins. These are true allergies, proteins that set off an immune response, not reactions to alcohol, biogenic amines, sulfites, or allergies to processing agents such as egg whites or milk proteins.
Seven of the 26 people prick-tested developed swelling in response to at least one of the wine or grape samples, four to wine and three just to grapes. 13 developed antibodies in response to grapes, but only nine of them had reported symptoms; the other four were in the asymptomatic control group. Only one person was wine allergy-positive in all four different types of tests.
The conclusion? People can be allergic to specific kinds of grapes, wines, or both, just as people can be allergic to citrus fruit, tomatoes, or olives. It’s probably not very common. This study was small, far too small to say anything about how common wine allergies are in Germany let alone amongst other ethnic groups. Knowing how to respond to discrepancies among the tests, and between the tests and people’s reported symptoms, is an issue, too. Writing up their results for publication, the researchers ignored it. But again, no matter what exactly is going on there, we’re back at the first conclusion. Grapes, and wine, seem to be like other foods as far as allergies go. You might well have a wine allergy, or an allergy to red or white wine, or to a specific variety. You probably don’t.