Food Allergies: A Case of Mistaken Identity

Nutrition expert Heather Reese breaks down the basics of common food allergies.

A food allergy occurs when the body mistakes a food item for a harmful substance, and the immune system creates antibodies to protect itself. Once this mistaken identity occurs, every time a person eats that food the body will release histamine and other chemicals, triggering an allergic reaction. This response can affect the respiratory, gastrointestinal and cardiovascular systems. It can also cause a skin reaction.

Common Food Allergens

While any food item can cause an allergic reaction, there are eight foods responsible for 90 percent of all food-related allergies. The eight common food allergens are:

• Eggs

• Fish and shellfish

• Milk

• Peanuts

• Soy

• Tree nuts

• Wheat

I will discuss each one in further detail below.


Experts estimate that about 12 million Americans have legitimate food allergies. And anyone can experience an allergic reaction to a food that had never been a problem before. These reactions can range from uncomfortable to life threatening and they usually develop about an hour after the food is ingested. Common symptoms include:

• Rash, hives and itching

• Swelling of the lips, face, tongue, throat and other body parts

• Wheezing, nasal congestion or dry throat

• Difficulty breathing

• Nausea, vomiting or diarrhea

• Dizziness, lightheadedness or fainting

The most severe allergic reaction is anaphylaxis, which can present as a constriction of the airway from a swelling in the throat or a lump that makes it difficult to breath. It can also result in shock or a severe drop in blood pressure, a rapid pulse rate or a loss of consciousness.

Risk Factors

While anyone can suffer from food allergies, there are factors that put you at an increased risk of developing them. A family history of even seasonal allergies can increase your risk of food allergies. Age is also a factor. Food allergies are most common in children and toddlers because as you age your body is less likely to absorb food allergens. While allergies to nuts and shellfish are usually lifelong afflictions, most other childhood allergies are outgrown.

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