Food Sensitivities, Allergies, and Intolerances

Reactions to Foods

Certain foods that we eat may not agree with us. Some foods can cause us to feel poorly, have poor digestion, cause a rash, or even kill us. There are three categories that refer to when we have an adverse reaction to a food we consume: a food allergy, a food intolerance, and a food sensitivity. Each category causes a different physiological reaction, and have a different root cause.

Food Allergy

          Some foods that we consume cause a hyper-immune reaction in our bodies. Basically, the body’s immune system views the food as a super-toxin, and reacts appropriately. Food allergies are mediated by IgE, and can be deadly. Usually a severe food allergy presents after an individual is pre-exposed to the food, for this allows the immune system to prime a response. Upon ingestion, immune cells react the food causing symptoms such as hives, airway inflammation, or swelling (1). Common food allergies include nuts and shellfish.

Food Intolerance

         A food intolerance differs from a food allergy in that it does not cause an immune response. Instead, a food intolerance refers to the body being unable to metabolize, digest, or absorb a food (3). In this case, the body may be lacking the enzymes or products needed to properly process a food. In lactose intolerant individuals, the most common food intolerance, individuals lack adequate enzymes to digest the lactose. Another common intolerance is FODMAPS, which are found in many vegetables, in which and individual lacks enzymes to digest fermentable carbohydrates (2).

Food Sensitivities

Food sensitivities are unique in that it is unclear whether a reaction to a food is immune-based or due to some other defect (3). A food sensitivity is an umbrella term to describe an adverse reaction that does not present as an allergy nor have indications of an intolerance (3). Individuals with a food sensitivity may present with symptoms similar to an allergy, such as inflammation or skin reactions, but do not show an adequate immune response to indicate an allergy.

References:

  1. Yu W, Freeland DMH, Nadeau KC. Food allergy: immune mechanisms, diagnosis and immunotherapy. Nat Rev Immunol. 2016;16(12):751-765. doi:10.1038/nri.2016.111
  2. Tuck CJ, Biesiekierski JR, Schmid-Grendelmeier P, Pohl D. Food Intolerances. Nutrients. 2019;11(7):1684. Published 2019 Jul 22. doi:10.3390/nu11071684
  3. Krause’s Food & the Nutrition Care Process by L. Kathleen Mahan; MNT for Adverse Reactions to Food: 14th edition Ch. 26