Allergy and food intolerance: two very different concepts

“ My child is allergic… “, we often hear. But is it really an allergy? In some cases, it’s more a question of intolerance. The two terms are often confused. Here are a few explanations to help you distinguish between food allergy and food intolerance.

Food allergy is a reaction of the entire immune system, while food intolerance mainly affects the digestive system. In both cases, symptoms can appear from a few moments to several hours after ingestion.

Food allergy: It’s all about the immune system. These are the body’s defense mechanisms, the immunoglobulins found mainly in the blood, which react to external pathogens such as allergy-triggering foods. So it’s the immunological system that reacts. The symptoms of the reaction can vary in severity, from hives or a tingling sensation in the mouth to asthma or a life-threatening reaction (anaphylactic reaction).

Food intolerance: Here, the immune system is not involved, but the digestive system. Food intolerance involves the metabolism, but not the immune system. Reactions are :

• Enzymatic: The origin is an enzyme deficit or deficiency which results in the inability to digest (completely) certain food components. For example, a lactase deficiency leads to intolerance to lactose, which passes through the intestine undigested, then stagnates and ferments in the colon, causing intestinal disorders throughout the digestive system.
• Pharmacological: This situation arises when the digestive system cannot tolerate certain substances such as histamine or tysorin. These substances are found in such foods as aged cheeses, smoked fish and fermented foods, chocolate, egg whites, strawberries, pineapple, exotic fruits, shellfish, fish, tomatoes and alcohol.

Reactions are not immunological, but are mediated by gastric juice (which sterilizes the food bolus), pancreatic enzymes (which break down proteins) and intestinal mucus (which coats food pathogens to eliminate them).

As the immune system is not involved in this area, it generally takes a much larger quantity to trigger a reaction, whereas in the case of an allergy, a tiny amount is all that’s needed.

Food intolerance is characterized by cramps, bloating, vomiting or diarrhea. A well-known food intolerance is lactose intolerance, which is an inability to digest lactose, the type of sugar found in milk.

While allergic children generally cannot tolerate the slightest amount of an allergen, intolerant people can tolerate small doses without showing any symptoms. There are exceptions, however, such as gluten and sulfite intolerance.

Your child may experience bloating, loose stools, gas or other symptoms after eating certain foods. Although this reaction is not dangerous, you may want to avoid certain foods if they cause this discomfort.

Example: Léa drinks milk.

– If she is lactose intolerant, she may have the following symptoms:

Diarrhea, vomiting, stomach ache (these symptoms usually depend on the amount ingested).

– If she is allergic to milk proteins, she may have the following symptoms:

Diarrhea, vomiting, stomach ache, accompanied by respiratory problems (runny nose, nasal congestion, wheezing, coughing) and circulatory problems (swelling of tissues that can cause choking, drop in blood pressure).

Diagnosing allergies remains a complex process. Even if intolerance is more unpleasant than dangerous, it’s important to play it safe and offer your child self-prepared foods, paying special attention to the reactions that can occur when a new food is introduced for the first time.

To learn more about the dynamics of allergies, we offer a training course for daycare educators and parents: Allergies? I react!