How do you know if your physical reaction to a food is the work of a food allergy, intolerance, or sensitivity? These three terms are often used interchangeably, yet they are three distinct conditions. Let’s break them down. (Except for intolerance – you’ll see!)
The National Institute of Allergy & Infectious Disease (NIAID) defines a food allergy as “an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food”.
The body mistakenly identifies a food protein as harmful and develops antibodies against it. When this item is consumed again, the body attacks it, releasing chemical mediators (such as histamine) and causing an allergic reaction. The top 8 food allergens account for 90% of all allergic reactions. They are: peanuts, tree nuts, eggs, dairy, wheat, fish, shellfish, and soy.
Common symptoms of a food allergic reaction include hives, itchiness, swelling, nausea, vomiting, throat tightness, coughing, and wheezing. Anaphylaxis is a more serious, life-threatening reaction involving more than one organ. Signs of anaphylaxis may include difficulty breathing, dizziness, and loss of consciousness. Food allergies are easy to identify because a reaction occurs every time the food item is consumed.
Food sensitivities, like food allergies, are immune-mediated, however through different pathways. Unlike allergies, food sensitivities can affect any organ system in the body, and may take as long as 45 minutes to several days to present.
Food intolerances differ from allergies and sensitivities as they do not involve the immune system. The response to a food item is localized to the digestive system only. A food intolerance is the inability of the body to properly digest, or break down, an item.
The most common intolerance is lactose. In this case the body is unable to break down lactose due to an inadequate amount or absence of the digestive enzyme lactase, which performs this function. As a result, the individual may experience bloating, loose stool, and gas.
Intolerance reactions are dose-related. Small amounts of an intolerant food product can build up over time, causing symptoms to develop without an easily identifiable cause. Individual reaction thresholds vary, and may not only fluctuate with different people, but within the same person. Thresholds may be lowered in times of stress or illness.
Here’s a chart to help you differentiate between the three:
A note on celiac disease: Celiac disease is NOT a food allergy, as it is widely regarded. In fact, is it is neither an allergy, sensitivity, nor an intolerance; it is an autoimmune disorder.
The immune system attacks its own body tissues, NOT gluten (as it would in an allergy). While celiac disease is an immune response, it does not involve IgE antibodies as a food allergy does.
Upon digestion of the proteins glutenin and gliadin found in gluten, the body sets in motion an inflammatory response. One result of this is damage to the small intestine, which can be a significant indicator of celiac disease. Individuals with a food allergy will not have this small intestinal damage.
Stay tuned for further discussion on food allergy prevention and prevalence.