Updated January 26, 2012.

If you've got a food allergy or intolerance, your diet is -- of course -- restricted through no choice of your own. In contrast, people choose to become vegetarian for any number of reasons. They range from the desire to see if avoiding meat will lead to better health or more energy, to the commitment to holding to strong religious or ethical beliefs, to concern about the safety of the food supply.

Whatever the motivation, combining multiple restricted diets can be challenging, and many people with food allergies are concerned about whether it's possible for them to get adequate nutrition on a vegetarian diet. Whether those concerns are justified depend in large part on which foods they're allergic to. Dairy and eggs, for instance, are excluded in conventional vegan fare, and many vegans eat healthy, varied diets.

Other food allergies, however, pose greater challenges for vegetarians. Vegetarian foods that cause allergies can be roughly divided into non-meat protein sources, foods used as grains, and fruits and vegetables, although some foods (for instance, wheat) fit into more than one category. Here's what you need to replace in your diet, some alternate foods to consider, and obstacles you're likely to run into if you're allergic to some especially common foods.

Allergies to Proteins

Most Common Examples: Soy, wheat (as seitan), peanuts, tree nuts

Why It's Important: Protein is essential for cell repair, growth, and development.

Your Body Needs: About four to six ounces daily for women, six to eight ounces daily for men (though some people may have higher or lower protein needs); this equates to forty-five grams for women and fifty-five for men.

Most foods, even green vegetables such as broccoli and cabbage, contain at least a small amount of protein. But some foods -- meat, dairy products, seafood, legumes, and some grains -- are much denser sources than others. Protein is one of the most common initial concerns of many people upon beginning a vegetarian diet, but in fact your body's protein needs are generally easy to meet with plant sources.

In the 20th anniversary edition of her book Diet for a Small Planet, Francis Moore Lappé claimed that, in general, people eating a sufficient number of calories would only be deficient in protein if their diets were highly dependent on a few very low-protein foods. That hasn't changed. Most people, even vegetarians, meet and even exceed their protein needs without even thinking about it. A few common allergens, however, are so frequently used as vegetarian proteins that they deserve special consideration.

Soy, in the form of tofu and tempeh, is a vegetarian staple. You'll find it in packaged vegetable broths, meal substitute bars, frozen meals, and as protein-rich "soy nuts" or "soy nut butter." If you're allergic to soy, it is possible to get adequate protein, but you'll need to be sure to plan your meals to get four to eight ounces of protein per day. You'll also find that many prepared vegetarian foods, especially dairy substitutes, are off-limits. You'll need to avoid meat substitutes, which are generally made from soy (some are made from wheat; check labels).

The other food most commonly used as a direct substitute for meat is wheat, in the form of seitan (wheat gluten). It's sometimes sold as patties and used in vegetarian chilis. Wheat is also a common binder in legume-based vegetarian burgers. Peanuts and tree nuts are sometimes used to make vegetarian burgers, though they're not common meat substitutes.

If you're allergic to one or more high-protein vegetarian protein sources, you'll need to meet your protein needs in other ways. Amaranth, quinoa, and teff are top choices. These three grains aren' very well-known in America, but are suitable for vegan diets, high in protein, and gluten-free. Whole-grain amaranth and quinoa are fairly easy to find, and quinoa-corn pasta blends are becoming more widely available at major supermarkets. Teff, an Ethiopian grain, may be more difficult to find, but some health food stores or grocery co-ops may stock it. You can find all of these grains for sale on the Internet at Gourmet Store.
Continued on Page 2: Allergies to Grains, Fruits, and Vegetables