— Christi Mansperger, Tempe, Arizona
A: Food allergies in general seem to be on the rise, though they affect only 2 percent of American adults. But I doubt that soy allergies result from eating too much of it: Research suggests the reason for a rise may be that we're introduced to soy so early. Exposure to certain food proteins in early infancy seems to prime a person's immune system for allergies. Soy-based baby formula is commonplace, and it's clearly one of the foods that triggers an allergic response. (The others are milk, eggs, fish, crustaceans, wheat, peanuts, and tree nuts.) Avoiding soy is tough. While it's easy to steer clear of obvious sources like tofu, tempeh, soy milk, and soy sauce, you'll have to be a careful label reader to spot it as a flavoring or thickener; it turns up under the names lecithin, monosodium glutamate (MSG), hydrolyzed vegetable protein (HVP), textured vegetable protein (TVP), vegetable gum, natural flavoring, vegetable broth—and that's just a few. The Mayo Clinic provides a complete list at MayoClinic.com. Your job has become considerably easier: The FDA is aware of the growing allergy issue and in 2004 set up the Food Allergen Labeling and Consumer Protection Act, which requires manufacturers to list common allergens.