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.

Symptoms

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.

Food Allergy vs. Food Intolerance

Not all food reactions are allergic. You can have a food intolerance, which results in many of the same symptoms, such as nausea, vomiting and diarrhea.

Many people confuse these food intolerances for allergies; however a reaction to a food intolerance does not involve the immune system. It is not a histamine reaction. Many people with food intolerances can ingest small amounts of the food item without a problem, whereas even a very small amount of a food one is allergic to will result in an allergic reaction. An example of food intolerance is lactose.

Food Allergy Considerations

If you do suffer from a food allergy, you can’t assume that simply avoiding the actual food that you are allergic to is enough. You must also read food labels and ask questions when dining out to ensure that you do not inadvertently ingest a food allergen that you have a reaction to. Below I summarize some additional considerations you should take in avoiding food allergens, but it is still important to be your own advocate and to always be aware of what you are eating.

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