Eight types of food are responsible for triggering almost 90 percent of known food allergies, according to the Food Allergy and Anaphylaxis Network. They are:

• Milk. Includes cheese, butter, cream, casein (a milk protein) and whey. A milk allergy should not be confused with milk intolerance, which is an inability to digest milk and not a true allergy.
  
  
• Wheat. Includes crackers, pastas, bread and malt. A wheat allergy should not be confused with gluten intolerance, which is a sensitivity to the protein gluten and not a true allergy.
  
  
• Soy. Includes lecithin (a food ingredient often made from soy), some types of baked foods, canned tuna, sauces and baby formulas.
  
  
• Peanuts. Includes peanut butter, “gourmet” peanut oil (includes cold-pressed, expelled or extruded), many types of ethnic foods (including Chinese, Indonesian, Thai, Vietnamese and possibly Mexican) and some flavorings.
  
  
• Tree nuts. Includes hazelnuts, cashews, almonds, walnuts, pecans, Brazil nuts and others.
  
  
• Shellfish. Includes crab, crayfish, shrimp, clams and lobster.
  
  
• Fish. Includes yellowtail, salmon, mackerel, tuna and hake.
  
  
• Eggs. Includes commercially processed cooked pastas, mayonnaise and some brands of egg substitutes.

Other food allergies are less common, but significant because of the popularity of their trigger foods:

• Corn. This allergy is triggered by corn protein and is notable because of the large number of food products that contain corn-based ingredients.
  
  
• Rice. This rare allergy can be triggered through both ingestion and inhalation (of rice pollen). It has a much more common occurrence in geographies where rice is regularly served – such as Japan.

Among adults, shellfish, peanuts, tree nuts and fish are among the most common triggers for food-related allergic reactions. In children, eggs, milk, peanuts, soy and wheat are most often the cause.

As noted earlier, even trace amounts of an allergen can provoke a reaction. For instance, foods sold in bakeries and ice cream parlors often come into contact with surfaces contaminated with peanuts. Processed foods also may come into contact with allergen particles. In both cases, this can be enough to cause an allergic reaction in highly susceptible individuals.

Some people have expressed concern over the dangers potentially posed by the increasing use of genetically modified foods (GMOs). While there have been no studies to indicate GMOs are dangerous, the introduction of new kinds of proteins could trigger previously unknown types of allergies in some people. Research designed to guard against the release of any new genetically modified allergens is ongoing.

Clinical research suggests that a nursing mother who has a history of allergies in her family may be able to prevent or delay passing on a food allergy to her child by avoiding common trigger foods. By staying away from foods such as milk, soy, eggs and peanuts, a nursing mother may keep her young child free of the proteins that can trigger a food allergy. Though physicians almost unanimously agree that there are benefits to children who are breastfed, there is currently no clinical evidence that this method can, in fact, prevent allergies in children.