Food Allergy vs. Food Intolerance

A common type of allergic reaction is a food allergy. The most common foods that elicit allergic reactions are peanuts, tree nuts (such as walnuts, pecans and almonds), shellfish, dairy and wheat, but allergic reactions can be caused by any food.

A food allergy is actually an immune-system response. When someone eats certain foods (such as those listed above), the body mistakenly treats an ingredient in the food (usually a protein) as if it were a harmful pathogen. The body responds by creating a defense system (antibodies) to fight it. The allergic symptoms occur as a byproduct of the action of the antibodies that battle the invading food.

Food intolerance is a broad term that describes any adverse reaction to food. While only a small percentage of all food intolerance can be proven to be a food allergy, a food-allergic reaction can be dangerous, even fatal (please see below).

Non-allergic food intolerance is often limited to an uncomfortable digestive-system response. The most common example of food intolerance is lactose intolerance, in which one’s body is unable to break down the sugar (lactose) in dairy products. Other food intolerances can be caused by irritation to the digestive system by an ingredient in the food consumed.

There are no medications that can cure food intolerance. The only way to prevent a reaction is to avoid that particular food or food group. In the case of lactose intolerance, lactose-free dairy products are widely available. There is also over-the-counter medication, such as Lactaid, that can be taken before eating dairy products to help reduce abdominal symptoms. This medication works by breaking down the lactose that the digestive system cannot break down by itself.

Medications may be used to help reduce relatively minor allergic reactions to foods such as itching skin rashes (hives). However, a major allergic reaction to a food may rapidly affect the entire body, sending it into shock. This is called anaphylaxis, which can be fatal. Anaphylactic shock can obstruct breathing and shut down oxygen-carrying blood flow to vital organs of the body, including the brain.

Food allergies can be challenging to manage because there is no treatment that can cure the problem. Currently, a food allergy is best managed by completely avoiding the food (such as peanuts) or food category (such as tree nuts or shellfish).

People with food allergies should carry an EpiPen with them at all times. EpiPens are small automatic-injection devices that contain epinephrine (also called adrenaline). EpiPens can be used to self-administer epinephrine event of an unforeseen, serious allergic reaction. If a major allergic reaction of this kind occurs, emergency medical care must be sought immediately, even if injected epinephrine has been used.