The Difference Between Food Allergies and Food Intolerances

The Difference Between Food Allergies and Food Intolerances

People often say that they cannot eat a certain food because they are allergic to it. But the vast majority of the time, the person is not truly allergic to the food; instead, they have a food intolerance. Although it is technically possible that some of the symptoms produced by food allergies and food intolerances may appear similar, the symptoms usually differ in significant ways. Let’s take a look at the key differences starting with allergens.

The top eight food allergens are milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans, accounting for 90 percent of the food allergies in the U.S. Under the Food Allergen and Customer Protection Act, these major allergens must be listed on a food label. Although more than eight foods can cause an allergic response, only the top eight allergens are required to be listed.

Do certain foods cause you to experience gas, bloating, and chronic diarrhea?

A food allergy elicits a response from the immune system.

When an individual with a food allergy consumes an allergen, the body recognizes the allergen as a foreign invader, and the body over responds and produces antibodies. The antibodies, called Immunoglobulin E (IgE), attach to cells and cause them to release specific chemicals like histamine. When the chemicals are released, an allergic reaction occurs.

The reaction timing of a food allergy differs from that of a food intolerance. When a person with a food allergy ingests an allergen, an immediate reaction can occur, causing symptoms that range from mild to life-threatening. For some individuals, the allergy can cause symptoms that manifest on the skin in the form of hives or rashes. For others, gastrointestinal symptoms like diarrhea and vomiting may develop which is why some people confuse a food allergy with a food intolerance.

Those with a severe food allergy can have a life-threatening reaction called anaphylaxis. Just like a food intolerance, there is no cure for a food allergy, so those with food allergies must be very careful to avoid the allergen. Some individuals are so sensitive that even touching the allergen or breathing it in can cause a reaction.

On the other hand, food intolerances are generally much more common.

The most common food intolerances are dairy, sulfites, gluten, and fructose. And another less common intolerance is sucrose. But a food intolerance is very different from a food allergy. As previously mentioned, a food allergy involves the body’s immune system.

When a food intolerance occurs, the immune system is not involved and the intolerance cannot be immediately life-threatening. Instead, the digestive tract is the source of the problem. A food intolerance occurs when an individual is unable to digest a specific food component. Often, the intolerance is caused by the lack of an enzyme needed to break down a specific food component.

For example, those with Sucrose Intolerance caused by Congenital Sucrase-Isomaltase Deficiency (CSID), are unable to break down sucrose (table sugar) because they lack the sucrase enzyme. Unlike the instant reaction of a food allergy, a food intolerance usually produces undesirable symptoms at a delayed rate. Some individuals can ingest an offending food and not have symptoms until 48 hours later.

The symptoms of a food intolerance vary but commonly include gas and bloating, diarrhea, stomach pain, and nausea. While those with a food allergy must avoid the allergen, those with a food intolerance may tolerate small amounts of the offending food. For example, some individuals with CSID may find that small amounts of sucrose in their diet do not produce symptoms. However, like a food allergy, a food intolerance cannot be cured, it must be managed throughout a person’s life.

In summary, if those with a food intolerance eat an offending food, it will likely make them feel ill for a short period of time. However, for those with a food allergy, the response to the allergen could be life-threatening. Although the words “allergy” and “intolerance” seem to be used interchangeably by many people, they are very different and cause different reactions in the body. So it is really important that people understand if they truly have a food allergy or if they just have a food intolerance.


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Sucrose Intolerance May Be More Common Than You Think