What are Food Allergies?

The human immune system normally fights off bad bacteria or viruses that make people sick.  A food allergy occurs when the immune system targets harmless food molecules as a harmful invading allergen and mobilizes to attack and get rid of the offending substance.   True food allergies cause the body to produce abnormally large amounts of an antibody called immunoglobulin E — IgE for short.   IgE antibodies fight the “enemy” food allergens by releasing histamine and other chemicals, which trigger the symptoms of an allergic reaction, including anaphylaxis, a potentially life-threatening reaction.  Anaphylaxis can affect several areas of the body and threaten breathing and blood circulation. There is no cure for food allergies.  Strict avoidance of food allergens — and early recognition and management of allergic reactions to food — are important measures to prevent serious health consequences.

A food allergy is different from food intolerance.  Except for celiac disease (see Wheat & Gluten below), food intolerances do not involve the immune system.   A person with food intolerance is sensitive to certain foods and has difficulty digesting them.  Some food intolerances may cause some of the same symptoms as a true food allergy, but they cannot trigger anaphylaxis.

Other symptoms of food allergies include:

  • Respiratory symptoms might include difficulty breathing, sneezing, or wheezing
  • Skin symptoms can appear, such as hives or eczema
  • Digestive symptoms could show as diarrhea, cramping, or nausea

In 2004, the US Congress passed the Food Allergen Labeling and Consumer Protection Act (FALCPA) which is intended to warn consumers and help them avoid food allergens. The law applies to all foods whose labeling is regulated by the FDA, both domestic and imported.   While more than 160 foods can cause allergic reactions in people with food allergies, the law identifies the eight most common allergenic foods.  These foods account for 90% of food allergic reactions and are the food sources from which many other ingredients are derived.  The eight foods identified by the law are: milk, eggs, fish (e.g., bass, flounder, cod), crustacean shellfish (e.g. crab, lobster, shrimp), tree nuts (e.g., almonds, walnuts, pecans), peanuts, wheat, and soybeans.  These eight foods, and any ingredient that contains protein derived from one or more of them, are designated as “major food allergens” by FALCPA.

Why this matters:

Natural food retailers are required by FALCPA to display signs warning customers about exposure to food allergens in the bulk department and on items that retailers package in their store, warehouse or commissary. 

Peanuts & Tree Nut Allergies

Peanut allergy is one of the most common food allergies and appears to be on the rise in children in the last decade.  According to one study, the number of children in the US with peanut allergy more than tripled between 1997 and 2008.   Peanuts can cause a severe, potentially fatal, allergic reaction (anaphylaxis).   Peanut allergies tend to last throughout life, although studies indicate that approximately 20 percent of children with peanut allergy do eventually outgrow their allergy.   Even trace amounts of peanut can cause an allergic reaction.  However, casual contact with peanuts, such as touching peanuts or peanut butter residue, is less likely to trigger a severe reaction unless the area that comes into contact with peanuts then comes into contact with the eyes, nose, or mouth (for example, a child with peanut allergy gets peanut butter on her fingers, and then rubs her eyes).

People with a peanut allergy are advised to have quick access to an epinephrine auto-injector at all times. To prevent a reaction, strict avoidance of peanut and peanut products is essential.  Staff and customers should always read ingredient labels to identify peanut ingredients before the product is purchased.

Peanuts are not the same as tree nuts, which grow on trees.  Peanuts grow underground and are part of the legumes plant family.   Other legumes include beans, peas, lentils, and soybeans.  People who are allergic to peanuts do not have a greater chance of being allergic to another legume (including soy) than they do to any other food.  Tree nuts include, but are not limited to, walnut, pecans, pine nuts, almond, hazelnut, cashew, pistachio, and Brazil nuts.  A person with an allergy to one type of tree nut has a higher chance of being allergic to other types.  Most experts advise patients with tree nuts allergies to avoid all products that contain nuts or ingredients produced from nuts.  

Why this matters:

Because of the complexity and varying severity of food allergies, it is often difficult to diagnose a food allergy. Often a person can suffer from symptoms of a food allergy unknowingly for years. Once an allergy is identified, they often come to health food stores looking for allergen-free products.

Nut-free products may be manufactured in the same facility as peanuts or other tree nuts.   As a result, there is a higher likelihood of cross-contact with nut ingredients during manufacturing and processing.  Manufacturers are now required to disclose any nut-free product that is made in the same facility as products with peanuts or tree nuts.  Retailers who produce or package any items in their warehouses, back rooms, or deli departments must clearly label any nut item and include risk of nut contamination on the label.   When sampling items for customers, staff should thoroughly read product labels to check for specific nuts, peanuts, peanut butter, or peanut oil, and be sure to include this information on sampling signs. 

Nut-free substitutes for peanut butter include sesame butter (made from whole sesame seeds), tahini (made from hulled sesame seeds), Sunbutter (made from sunflower seeds), or other nut butter made from acceptable nuts for customers who are allergic to peanuts but not to tree nuts. 

Milk & Lactose

A milk allergy is an abnormal response by the body's immune system to two main proteins in cow's milk that can cause an allergic reaction:  Casein, which is found in the solid part (curd) of milk that curdles, and Whey, which is found in the liquid part of milk that remains after milk curdles.   Cow's milk is the usual cause of milk allergy, but milk from sheep, goats, and buffalo also can cause a reaction.  Milk allergy is one of the most common food allergies in children.  Fortunately, most children outgrow a milk allergy by age 3.  An allergic reaction usually occurs minutes to hours after consuming milk. Signs and symptoms of a milk allergy range from mild to severe and can include wheezing, vomiting, hives, and digestive problems.  Rarely can a milk allergy cause anaphylaxis.

A milk allergy is different from Lactose intolerance.  People who are lactose intolerant are missing the enzyme lactase, which breaks down lactose, a sugar found in milk and dairy products. Undigested lactose ferments in the intestine producing gas, bloating, diarrhea, nausea, and cramps.  While lactose intolerance can cause great discomfort, it is not life-threatening.  Some people with lactose intolerance can digest yogurt and other cultured milk products because the lactose is digested by the bacteria in the fermented food.  Sometimes people can still generate small amounts of lactase themselves and may be able to tolerate some dairy products but not others.   

There are a number of refrigerated, frozen, and packaged grocery products that are dairy and lactose-free.   Course 102 Grocery, Lesson 2 Dairy & Eggs covers alternative milk products. 


Most people with egg allergies are allergic to egg whites, not the yolk. But to be safe, people allergic to eggs shouldn’t eat either the white or the yolk because it is impossible to separate the egg white completely from the yolk, causing a cross-contamination problem.  Individuals with egg allergies should also avoid eggs from duck, turkey, goose, quail, etc., as these are known to cause reactions similar to a chicken egg. 

Why this matters:

The only way to know for sure if a food has eggs in it is to read the food label and ingredients list carefully.  The federal Food Allergen Labeling and Consumer Protection Act (FALCPA) requires that all packaged food products sold in the U.S. that contain egg as an ingredient must list the word “Egg” on the label.  This is true for all food allergens.

Egg powder, dried eggs, egg solids, and all ingredients made from egg should be avoided.   Eggs are used in a wide range of foods for a variety of reasons, from helping baked goods rise to emulsifying salad dressings.  Eggs can be found in breaded foods, coffee drinks, lollipops and candies, lecithin, macaroni, marzipan, marshmallows, nougat, pasta, sauces, and even egg substitute.   Eggs are not always an obvious ingredient in foods.  For example, ingredients such as albumin (also spelled albumen), dried or powdered eggs, egg solids, egg white, egg yolk), globulin, lysozyme, mayonnaise, meringue & meringue powder, ovalbumin, ovovitallin, simplesse, and surimi should be avoided.   

Egg Substitutes

  • There are egg replacement products made from arrowroot, baking powder, tapioca, and potato starch, typically found in the baking or dairy sections. 
  • A popular, nutritious homemade substitute is flaxseed.   Mix 1 part ground flaxseed with 3 parts cold water.   Boil for three minutes, then cool and store in the refrigerator.  For 1 beaten egg, substitute 1 tablespoon of the flaxseed mixture.
  • Garbanzo flour can also be used as an egg substitute. Use 1 tablespoon flour plus 1 tablespoon oil to replace 1 egg.


Soy allergies can cause symptoms from mild to severe.  Soybeans alone are not a major food in the American diet, but in the Japanese diet soybeans and products made from soybeans are major contributors.   In the United States, soybeans are widely used in processed food including baked goods, canned tuna and meat, cereals, cookies, crackers, high-protein energy bars and snacks, infant formulas, low-fat peanut butter, processed meats, sauces, and canned broths and soups.   Soy can also be found in vegetable gum, vegetable starch, vegetable broth, glycine max, hydrolyzed vegetable protein (HVP), mono-diglyceride, and monosodium glutamate (MSG). 

Traditional soy products include:

  • Edamame
  • Miso
  • Natto
  • Shoyu
  • Soy (soy albumin, soy cheese, soy fiber, soy flour, soy grits, soy ice cream, soy milk, soy nuts, soy sprouts, soy yogurt)
  • Soya
  • Soybean (curd, granules)
  • Soy protein (concentrate, hydrolyzed, isolate)
  • Soy sauce
  • Tamari
  • Tempeh
  • Textured vegetable protein (TVP)
  • Tofu

Wheat Allergies & Gluten-Free Diets

Although most people tend to lump wheat allergies, gluten intolerance, and celiac disease into one issue, each of these is different.  Allergies to wheat generate symptoms similar to pollen and dust – histamine reactions including itching and swelling of the mouth, throat, or skin, itchy, watery eyes, and in more severe cases, the closing of the throat and difficulty breathing.  Celiac disease, on the other hand, is an auto-immune reaction to eating gluten – a protein found in wheat, barley, and rye – that causes inflammation in the small intestine, damaging the small intestine's lining and preventing absorption (malabsorption) of some nutrients, leading to weight loss and other health problems.   About 1% of the US population suffers from celiac disease. However, some report that as many as 1 in 7 people are intolerant of gluten and experience symptoms similar to those with celiac disease, yet lack the same antibodies and intestinal damage found in true celiac disease.  

Why this matters:

According to newhope360.com, an industry website, 1 in 133 people in the U.S. are affected by celiac disease; the majority is undiagnosed.  And 6–7% of the population is thought to have non-celiac gluten sensitivities.  As a result, the gluten-free foods market boomed in 2012 growing 17% in one year, estimated at $4.2 billion.   This growth will continue because a whopping 29% of Americans say they are trying to avoid gluten for health reasons, according to NPD Group, a worldwide consumer research and advisory group.  The expected size of the gluten-free category by 2017, will be $6.6 billion according to Packaged Facts.

People with wheat allergies and celiac disease must eliminate all items containing gluten from their diet.  Baked goods, brans, bulgur and wheat germ, couscous, all types of wheat flours, hot or cold cereals, pasta, ales and beers, hot dogs and processed meats, salad dressing, sauces and soups, soy sauce, and even ice cream can contain gluten.  Sometimes it is not readily apparent that a product can include wheat or gluten ingredients.  These are sometimes called “hidden wheat.”  An example of “hidden wheat” is tamari or soy sauce.  Most contain wheat; however, wheat-free tamari is available in most health food stores.   Some other ingredients that contain the gluten protein include gelatinized starch, hydrolyzed vegetable protein (TVP, malt, natural flavorings, starch (including modified starch and modified food starch), and vegetable gum.  “Hidden wheat” can also be found in health and beauty products such as lip gloss that contains hydrolyzed wheat protein.  Stamp and envelope glues, toothpaste, lip balms, and shampoos can contain gluten.  For people with celiac disease, a bit of gluten that might get swallowed from a lipstick or a stream of shampoo in the shower can be enough to cause illness.    

Most people who are sensitive to wheat typically have reactions to common wheat (Triticum aestivum).  Some people find they can tolerate Spelt (Triticum spelta) and Kamut. Both contain gluten and should be avoided by all people with celiac disease or high gluten sensitivity. Spelt and Kamut are ancient, nutritious grains that have not undergone the same evolution as common wheat. Some people with wheat sensitivities find they can tolerate digesting Spelt and Kamut, despite their close relationship to wheat and the presence of gluten. 

Many highly nourishing grains that do not contain gluten are available to consumers. These include quinoa, amaranth, teff, and buckwheat, etc. Gluten-free grains as well as Gluten-free flours, baking mixes, bread mixes, cookies, and pasta are readily available at natural food stores and are often merchandised in their own section and highlighted with Gluten-Free signage. 

Other wheat alternative products typically found in natural food stores include:

  • Corn tortillas, rice cakes, and mochi are good substitutes for wheat crackers.
  • Ready-made, wheat-free cereals include cream of rice, cream of buckwheat, puffed rice, puffed millet, puffed corn, rice flakes, corn flakes, brown rice crispies, and wheat-free granola.
  • Corn germ can replace wheat germ and oat bran replaces wheat bran.
  • Cooked amaranth, buckwheat, polenta, millet, and oats can replace cracked wheat or couscous in salads or in main dishes, and can also be used as hot cereals.
  • Rice, corn, lentil, quinoa, buckwheat, or mung bean pasta can be substituted for wheat pasta.
  • Potato flour is becoming a common wheat replacement in gluten-free bread.

A Note about Corn:   People with gluten allergies may also be very sensitive to corn and suffer from similar symptoms.  Some of this may have come from gluten cross-contamination during the growing and manufacturing processes.   However, science is looking into the structure and behavior of the amino acids in corn to see how similar they may be.   In addition, 90% of corn grown in the United States is genetically modified which is said by some experts to cause leaky gut syndrome. 

Fish & Shellfish

About 7 million Americans are allergic to seafood, both finned fish and shellfish.  Shellfish allergies can cause severe reactions, including anaphylaxis.  The allergy is typically life-long and is first experienced as an adult.   There are two kinds of shellfish:  crustacea (such as shrimp, crab, and lobster) and mollusks (such as clams, mussels, oysters, and scallops).  Shrimp, crab, and lobster cause most shellfish allergies, and the reactions to crustacean shellfish tend to be particularly severe.   Some people who are allergic to one group of shellfish might be able to tolerate shellfish from the other group.  However, to prevent a reaction, strict avoidance of shellfish and shellfish products is essential.  Finned fish and shellfish do not come from related families of foods, so being allergic to one does not necessarily mean that both should be avoided.  Salmon, tuna, and halibut are the most common kinds of finned fish to which people are allergic. 

A common question from people who are allergic to fish is if omega-3 fatty acids from fish oil are safe to consume.   Since the allergy is caused by proteins, it would follow that fish oil should be safe.  However, if fish oil is not handled and manufactured correctly, there is a risk of cross-contamination and exposure.   So most experts recommend that people allergic to fish avoid fish oil omega-3 fatty acids and instead consume spirulina, or vegetable omega-3s from flaxseed, pumpkins seeds, walnuts, and other sources.  


Words to Remember


A potentially life-threatening reaction to food allergens that cause airway restriction, extremely low blood pressure, skin, and intestinal irritation, and altered rhythms. In severe cases, it can result in complete airway obstruction, shock, and death.



Is a milk protein found in the solid part (curd) of milk that curdles which may contribute to allergic or intolerance reactions.



A disease that is caused by the body’s allergic reaction to gluten, a protein found in wheat, barley, and rye. The recurring immune response produces inflammation that damages the intestine’s lining and prevents the absorption of nutrients.



A condition where the immune system targets harmless food molecules as harmful invading allergens and produces abnormally large amounts of an antibody that triggers an allergic reaction, including anaphylaxis.



Is the body’s sensitivity to a food or ingredient which can cause digestion problems, and other symptoms similar to allergies, but does not trigger anaphylaxis.



A mixture of two proteins that are found in certain grains which creates the elastic texture of the dough and is also the cause of Celiac disease.



Is a sugar found in milk and dairy products that may contribute to allergic or intolerance reactions.



A milk protein that is found in the liquid part of milk that curdles may contribute to allergic or intolerance reactions.

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