Food Allergies & Intolerances

By Kara Ten Kley, Registered Dietitian

What are Food Allergies?

The term allergy actually defines a variety of physical responses the body makes to foods we eat. A true "food allergy" is an abnormal response by the body's immune system to specific foods or food ingredients. For some people, eating even a little of the offending food can cause a life threatening reaction. This most severe type of response is called anaphylaxis, pronounced AN-a-fy-LAK-sis. It can happen almost immediately after eating the food and typically involves several parts of the body. The symptoms may include difficulty breathing, hives, and loss of consciousness.

Less sensitive people may be able to eat small amounts of the offending food. One out of three people believe they have a food allergy but only 1% of adults suffer a true allergy.

What is the difference between an allergy and intolerance?

A food intolerance does not involve the immune system. However, the symptoms can resemble those of a true allergy. For this reason, a person should be evaluated by a certified allergist.

What are common symptoms of food allergies and intolerances?

Physical responses to both can include skin reactions, nose/lung reactions and stomach/intestinal reactions. The symptoms can come immediately, within two hours, or as long as one to two days after eating the allergen.

What foods commonly cause food allergies?

In adults, fish, shellfish, peanuts, other nuts such as walnuts or pecans, and eggs are common. In children, milk, eggs, peanuts wheat and soy are common culprits.

What might cause a food intolerance?

  • People can react negatively to foods because of digestive and other physical conditions.
  • An enzyme deficiency, such as in the case of milk intolerance where the body can not adequately breakdown the lactose (sugar) in the milk.
  • Natural substances in some foods like wine, fish and cheese may cause allergy like symptoms.
  • Food additives are rarely linked with intolerances.

What can someone do to manage food allergies?

Once a true allergy has been diagnosed, strictly avoiding the substance is necessary. Your registered dietitian and M.D. can help you make the appropriate food substitutions and help you change your diet.