Food Allergens

What are food allergens?

The environment around you is full of foreign substances. Exposure to foods, primarily through ingestion, results in symptoms and discomfort in people with food allergies.

Virtually any food can trigger an allergic reaction, but here are nine foods that cause the most reactions. These foods are considered major allergens and their presence is required by law to be declared on all packaged food items.

Milk⁷⁸

Milk allergy stems from an immune reaction against proteins in milk, commonly cow’s milk. The significant allergens belong to casein proteins (alpha-s1-, alpha-s2-, beta-, and kappa-casein) and whey proteins (alpha-lactalbumin and beta-lactoglobulin).

Whey is more allergenic than casein, but luckily it is heat-labile. Many children with a milk allergy can tolerate baked milk because they are only allergic to whey proteins and not heat-stable casein proteins, but allergies to both are possible.

Infants and children are commonly diagnosed with milk allergy, but the allergy can regress by age 6. A non-IgE-mediated mechanism most frequently causes cow's milk allergy, but an IgE-mediated allergy is still quite prevalent.

Common foods that contain milk allergens

Cow’s milk, butter, cheese, yogurt, cream, ice cream, sherbet, goat’s milk, sheep’s milk, processed foods, or any food with “Milk” listed as an allergen.

Milk Alternatives

Cow’s Milk: Breast milk, camel’s milk, hemp milk, rice milk, coconut milk, tree nut milk (almond, cashew, hazelnut, walnut, etc.), oat milk, pea milk, banana milk, and soy milk*.

Butter: Soy butter*, vegetable oil butter, tree nut butter, pumpkin puree, vegetable shortening, avocado, apple sauce.

Cheese: Soy cheese*, tree nut cheese, sweet potato, potato, nutritional yeast, avocado.

*Soy may not be a good alternative for children with milk allergies as many are prone to also developing soy allergies.

Egg⁷⁹

Egg allergy stems from an immune reaction against proteins in eggs, commonly hen’s eggs. The significant allergens belong to egg white proteins (ovalbumin, ovomucoid, ovotransferrin, lysozyme) and egg yolk proteins (serum albumin and YGP42).

Egg white is more allergenic than egg yolk, but luckily many proteins in both are heat-labile and their allergenicity is greatly reduced when heated; ovalbumin, ovotransferrin, and lysozyme for egg white and serum albumin for egg yolk. Boiling eggs for at least 30 minutes is the best method for reducing allergenicity.⁸⁰

Infants and children are commonly diagnosed with egg allergy, but the allergy can regress by school age. Both IgE and non-IgE-mediated egg allergies are prevalent.

Common foods that contain egg allergens

Hen’s egg, goose egg, duck egg, mayonnaise, egg noodles, custard, sherbet, baked goods, processed foods, or any food with “Egg” listed as an allergen.

Egg Alternatives

Egg is hard to replace but there are substitutes you can use for baking and mixtures: applesauce, banana, flax seed, seitan, tofu, and chickpeas.

Peanut⁸¹

Peanut allergy stems from an immune reaction against proteins in peanuts. The significant allergens are storage or plant defense-related proteins part of the Cupin superfamily (Ara h 1, 3), the Prolamin superfamily (Ara h 2, 6, 7, 9), the Profilin family (Ara h 5), Bet v 1-related PR-10 proteins (Ara h 8), Oleosin (Ara h 10,11), and Defensin (Ara h 12, 13). The Cupin and Prolamin superfamilies are the most allergenic as they have the highest prevalence of IgE binding.⁸²

The thermal processing of peanuts has an effect on their allergenicity when comparing raw, roasted, boiled, and peanut powder. Allergens in roasted peanuts are the most allergenic and most resistant to digestion, leading to the highest risk of sensitization. Raw peanuts are slightly less allergenic than roasted but still carry higher relative allergenicity. Boiled and peanut powder are the least allergenic and least resistant to digestion, carrying the lowest risk of sensitization, but are still not safe to ingest if you have peanut allergies.⁸³

Peanut allergy can appear at any age, but will typically show during the first few years of life. It is usually lifelong as it does not typically regress with age. An IgE-mediated mechanism most frequently causes peanut allergy, but a non-IgE-mediated allergy is still possible.

Common foods that contain peanut allergens

Peanuts, peanut butter, baked goods, African, Asian, and Mexican restaurant food, processed foods, or any food with “Peanut” listed as an allergen.

Peanut Alternatives

Almond butter, cashew butter, soy butter, sunflower butter, tahini, tree nuts, beans, and seeds.

Soy

Soy allergy stems from an immune reaction against proteins in soybeans. The significant allergens are storage or plant defense-related proteins part of the Cupin superfamily (Gly m 5, 6), the Prolamin superfamily (Gly m 8), the Profilin family (Gly m 3), Bet v 1-related PR-10 proteins (Gly m 4), and Defensin (Gly m 2). The Cupin and Prolamin superfamilies are the most allergenic as they have the highest prevalence of IgE binding.

Heating soy has little effect on the allergenicity of its significant allergens as they are mostly heat-stable. Allergens in soy are cross-reactive with casein proteins in cow’s milk, which explains why many milk-allergic children also experience allergies to soy.⁸⁴

Soy allergy is more common in infants and children than adults and the allergy can regress by school age. A non-IgE-mediated mechanism most frequently causes soy allergy, but an IgE-mediated allergy is still possible.

Common foods that contain soy allergens

Soybeans, tofu, edamame, miso, natto, soy sauce, soy milk, soy nuts, tamari, tempeh, teriyaki sauce, processed foods, or any food with “Soy” listed as an allergen.

Soy Alternatives

Soy-free labeled products, coconut aminos, chickpea, green peas, cashews.

Wheat⁸⁵

Wheat allergy stems from an immune reaction against proteins in wheat. The significant allergens are storage or plant defense-related proteins part of the Prolamin superfamily such as gluten (gliadin, glutenin) and Non-specific Lipid Transfer Proteins (nsLTPs).

Heating wheat has little effect on the allergenicity of its significant allergens as they are mostly heat-stable.

Wheat allergy is more common in infants and children than adults and the allergy can regress by age 12. A wheat allergy can be both IgE-mediated and non-IgE-mediated.

Common foods that contain wheat allergens

Bread, pasta, pizza, beer, cookies, baked goods, processed foods, or any food with “Wheat” listed as an allergen.

Wheat Alternatives

Rice, oats, potato, cassava, cauliflower, corn, chickpea, beans, almond flour, coconut flour, sorghum, quinoa, buckwheat, amaranth, arrowroot, millet, and teff.

Tree Nuts

Tree nut allergy stems from an immune reaction against proteins in tree nuts (almonds, brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pistachios, walnuts, etc). The significant allergens are storage or plant defense-related proteins part of the Cupin (globulin) and Prolamin (albumin, nsLTPs) superfamilies, or proteins part of the Profilin, PR-10, or Oleosin families.

Heating tree nuts have little effect on the allergenicity of their significant allergens as they are mostly heat-stable, but can reduce the allergenicity of their minor allergens part of the heat-labile Profilin or PR-10 families.

Some tree nuts are very closely related, so an allergy to one may signal an allergy to the other. Namely, walnuts/pecans and cashews/pistachios.

Tree nut allergy can appear at any age, but will typically show during the first few years of life. It is usually lifelong as it does not typically regress with age. An IgE-mediated mechanism most frequently causes tree nut allergy, but a non-IgE-mediated allergy is still possible.

Common foods that contain tree nut allergens

Nutella, pesto, baklava, pralines, nougat, tree nut flour, tree nut milk, cookies, baked goods, processed foods, or any food with “Tree Nuts” or the specific tree nut listed as an allergen.

Tree Nut Alternatives

Seeds, beans, pretzels, oats, raisins, chocolate chips, dried cranberries, or any tree nut that you aren’t allergic to.

Shellfish⁸⁶

Shellfish allergy stems from an immune reaction against proteins in shellfish. There are two groups of shellfish, crustaceans (crab, shrimp, lobster) and mollusks (clam, scallop, oyster, mussel, squid, octopus). Most people are allergic to only one group, but about 1 in 10 shellfish-allergic individuals are allergic to both.

The significant allergens are muscle-related proteins such as tropomyosin, arginine kinase, and proteins part of the EF-hand superfamily (myosin light chain, troponin, SCBPs). Interestingly, dust mites and cockroaches have very similar proteins to shellfish and are believed to be the major sensitizer for shellfish allergies.

Heating shellfish has little effect on the allergenicity of its significant allergens as they are mostly heat-stable.

Shellfish allergy can appear at any age. It is usually lifelong as it does not typically regress with age. An IgE-mediated mechanism most frequently causes shellfish allergy, but a non-IgE-mediated allergy is still possible.

Common foods that contain shellfish allergens

Fish sauce, fish stock, gumbo, jambalaya, scampi, cioppino, ceviche, bouillabaisse, seafood, or any food with “Shellfish” or the specific shellfish listed as an allergen.

Shellfish Alternatives

Fish, land animal meat, beans, tofu, or any shellfish that you aren’t allergic to.

Fish

Fish allergy stems from an immune reaction against proteins in finned fish (salmon, tuna, catfish, cod, etc). The significant allergen is a muscle-related protein called parvalbumin which is part of the EF-hand superfamily.

Heating fish has little effect on the allergenicity of its significant allergens as they are mostly heat-stable.

Fish allergy can appear at any age. It is usually lifelong as it does not typically regress with age. An IgE-mediated mechanism most frequently causes shellfish allergy, but a non-IgE-mediated allergy is still possible.

Common foods that contain fish allergens

Worcestershire sauce, fish sauce, fish stock, caesar salad dressing, sushi, ceviche, caviar, gelatin, cioppino, bouillabaisse, seafood, fish oil, omega-3 supplements, wine and beers clarified with isinglass, or any food with “Fish” or the specific fish listed as an allergen.

Fish Alternatives

Shellfish, land animal meat, beans, tofu, carrots, banana blossom, jackfruit, seaweed, seitan, and mushrooms.

Sesame

Sesame allergy stems from an immune reaction against proteins in sesame seeds. The significant allergens are storage or plant defense-related proteins part of the Cupin (globulin) and Prolamin (albumin) superfamilies, or proteins part of the Oleosin superfamily.

Heating sesame has little effect on the allergenicity of its significant allergens as they are mostly heat-stable.

Sesame allergy can appear at any age, but will typically show during the first few years of life. It is usually lifelong as it does not typically regress with age. An IgE-mediated mechanism most frequently causes tree nut allergy, but a non-IgE-mediated allergy is still possible.

Common foods that contain sesame allergens

Sesame seeds, sesame oil, tahini, hummus, baba ganoush, sushi, bread crumbs, margarine, baked goods, processed foods, or any food with “Sesame” listed as an allergen.

Sesame Alternatives

Other oils, poppy seeds, hemp seeds, flax seeds, sunflower seeds, chia seeds, pumpkin seeds, and tree nuts.

Other allergens

Since a person can be allergic to virtually any food, there are many other allergens that are not recognized by law. It is up to the individual to discover their allergy and learn how to navigate allergen avoidance. Here are some other food allergies that are less common, but still quite prevalent.

Fruits and Vegetables

Apple, banana, carrot, corn, peach, plum, tomato, watermelon, etc. You name it, any fruit or vegetable can be an allergen.

Many of these foods have allergens that are cross-reactive with pollen, so people with pollen allergies are prone to developing fruit and vegetable allergies.

An IgE-mediated mechanism most frequently causes fruit and vegetable allergy, but a non-IgE-mediated allergy is still possible. Oral Allergy Syndrome is a common IgE-mediated allergy related to raw fruit and vegetable ingestion.

Meat

Allergies to meat such as beef, pork, lamb, mutton, bison, and chicken also exist.

Heating meat can decrease the allergenicity of some allergens.

Gelatin

Gelatin is a protein that forms when an animal’s skin or connective tissue, commonly from a pig or cow, is boiled. Since animals are used, there is cross-reactivity with meat allergens.

Vaccines, vitamins, gummies, candy, marshmallows, ice cream, and Jell-O are all products that can contain gelatin.

Seeds

Sesame is one of the recognized allergenic seeds, but many other seeds such as sunflower seeds and poppy seeds have been known to cause allergies.

Spices

Many spices can cause allergies such as garlic, coriander, and mustard.

Spices have allergens that are cross-reactive with pollen, so people with pollen allergies are prone to developing a spice allergy.