Q: My wife's doctor recently told us that being allergic to yeast also means being allergic to most wines. Is this true? —John K.
A: Although baker's yeast and winemaking yeast are both strains of the same species, Saccharomyces cerevisiae, we think it's pretty unlikely that someone with an allergy to baker's yeast will react to wine. For those who are allergic, the problem isn't consuming something that was made with yeast; it's being in an environment where there's lots of yeast in the air. Explains Dr. Scott Nash, an allergist based in Raleigh, N.C., "We deal with a baker's yeast allergy more as an occupational problem than a consumer-related problem. People ingesting foods and drinks are typically not going to have a reaction." That is, the yeast can upset allergies when it's in its aerosolized form, coming into contact with people through their mucus membrane, their eyes and inhalation. In this form, those who are allergic may experience a runny nose, sneezing or wheezing. But this will really only affect "someone who does a lot of baking, as an occupation or as a hobby," Nash says.
In fact, he adds, those who deal with uncooked yeast professionally are more likely to be allergic to Saccharomyces than those who rarely encounter it, since "there's thought to be something about the constant and high level of exposure to the yeast that sensitizes them in the first place."
The allergen proteins break down as soon as they face some heat—and it doesn't take much heat, says Nash. "It doesn't take boiling; any process that would make something sterile is enough to break it down." So by the time you bite into a freshly baked loaf of bread, you're no longer coming into contact with the proteins that could provoke an allergic reaction.
As with baking bread, wine fermentation—whether done with commercial yeast or with the Saccharomyces native to the grape skins—should certainly generate enough heat to break down any allergen proteins. Moreover, "the amount of yeast ingested from a fermented product is low to nonexistent," Nash notes. He cautions, however, that you should consult an allergist if you observe ingestion reactions to products made with yeast.
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