Over the last 25 years, in westernized countries in particular, the prevalence of allergies in children and adults has soared. Challenge-diagnosed food allergy is as high as 10% in children. According to the AAFA, 50 million Americans experience some form of allergy.
While allergy is typically viewed as a dysfunction or a disease, evolutionary biologist Margie Profet brings a disruptive perspective to our understanding of the phenomenon.
In The Function of Allergy (1991) written before the allergy crisis, Margie Profet proposed that allergy is an evolved protective response with a purpose. This uncomfortable and potentially risky immune system response that we are all programmed to create, has a function. Allergy, she suggests, is a “last line of defense against toxic substances in the environment in the form of secondary plant compounds and venoms.”
Consider our range of defenses against toxins: the senses of smell and sight, peeling and cooking, enzymatic destruction and elimination, methylation, and more. However, if something such as penicillin overwhelms our abilities to detoxify it, the body will create a defense that is commonly IgE antibody mediated. Once sensitized to a specific compound, this patrolling antibody will trigger a chemical cascade in response to its presence.
This cascade results in the familiar signs of an allergic reaction: hives and itchy skin, sneezing, and coughing may be accompanied by vomiting, diarrhea and much more. These biochemical responses, Profet says, are attempts to block or eject the perceived threat – one that had previously overwhelmed our ability to remove it.
In short, for Profet, the potential for allergic sensitization and the ability to detoxify are inversely related.
M. Profet, “The Function of Allergy: Immunological Defense Against Toxins,” The Quarterly Review of Biology 66, no. 1 (1991). https://pubmed.ncbi.nlm.nih.gov/2052671/