Is It An Allergy?
The difference between food sensitivity, food allergies, and autoimmunity
I've been out to dinner with friends who have celiac disease and noted that deer-in-the-headlights look when the server asks "Is it an allergy?" That shorthand might work for a busy restaurant but it's not always an accurate description of the ways in which a body can react to gluten. For a person with celiac disease, the response inside her body is an autoimmune one — not an allergic one.
Given the advent of spring, and the distant hum of a lawnmower, I'm inspired to take a closer look at the body's allergic response, this week — food allergies, in particular, and the ways in which those differ from food sensitivities and autoimmune disease.
Any allergic response is generally considered a more immediate reaction to triggers like pollen, dust, animal dander, certain foods and fungus spores like mold. It starts when you inhale, swallow, or brush up against something you're allergic to, at which point your body starts to combat the allergen, releasing histamine and other inflammatory molecules (prostaglandins, leukotrienes) into the bloodstream, which provoke symptoms.
Nearly a hundred years ago, researchers discovered an important clue to hay fever — a common complaint with a fairly immediate allergic reaction: an itchy nose, a bout of sneezing, watery eyes. That biochemical clue was an immunoglobin called IgE, found in our tissue and bloodstream. Today, the science of Allergy & Immunology has mapped all sorts of allergic reactions and IgE remains an important marker.
Other immunoglobins with slightly different structures (IgG, IgM, IgA and IgD) mark other functions and dysfunctions in the body. If you've been diagnosed with celiac disease, you're familiar with IgA, which can be found in high concentrations in the gastrointestinal mucosal tissues or GALT.
What are these helpful immunoglobins and how do they mark a potential health issue? They’re antibodies — proteins launched by the immune system to defend against a perceived invader. If you’ve got elevated levels of these antibodies, something’s going on.
Food allergy falls into the IgE-related category. Though it's sometimes described as a sensitivity or intolerance, a food allergy actually provokes a reaction in the respiratory, digestive or skin systems: asthma, itching, hives, and sneezing, for example. The more immediate the reaction, the more accurately the source of distress can be identified. Given a delay in symptom onset, a person could be experiencing a food sensitivity — provoking an IgG reaction — and the source of distress can be harder to pinpoint.
More immediate-onset allergic responses can result in anaphylaxis. Anaphylaxis develops rapidly and can even lead to death. A life-saving dose of epinephrine, injected with an epi-pen, is the primary treatment and can help the patient avoid anaphylactic shock.
Why are some people so severely allergic to triggers in the environment or to the food on a menu? An allergic response is considered an overreaction of the immune system that's become sensitized through diet, environmental toxins and digestive stress. Damage to the gut microbiome has been shown to both worsen an allergic response and increase the incidence of autoimmunity. Addressing this root cause of immune dysfunction can bring the body's allergic response back under control. In terms of an effective approach to healing, allergies are similar to autoimmunity.
What are the differences between allergies and autoimmune diseases?
Last week, we took a look at autoimmune disease as the outcome of an overwrought immune system. Allergies are another common result of a dysfunctional system. In each case, the immune response is triggered but the targets are different. In a person with autoimmune disease, the immune system mistakenly attacks healthy tissue. In a person suffering from allergies, the immune system goes after environmental triggers. Thereby, allergies and autoimmunity present with different symptoms. An area of current research is the correlation — even the causal connection — between food sensitivities, allergies and autoimmune disease.
Let's look at autoimmune thyroid disease, for instance, and the role that gluten can play.
A gluten sensitivity can feel as harmless as a gut-based discomfort — a simple bloated feeling — or an unusual sleepiness, after a meal. Symptoms could increase, signaling that a component of gluten — a protein called gliadin — is actually harming the body. Gliadin elevates a molecule called zonulin — an inflammatory protein and gatekeeper of the gut that regulates the space between the cells in the intestinal wall. As these spaces widen, partially digested particles of food that contain gluten can introduce gliadin into the bloodstream — the damaging outflow of a leaky gut, which we discussed last week. Gliadin resembles the protein of the thyroid gland — a phenomenon referred to as molecular mimicry. The immune system, alert to things that are in the wrong place, creates antibodies against gliadin to prepare the body for the next invasion. These antibodies cause the immune system to mistakenly attack the thyroid tissue, as well.
An autoimmune disease is up and running.
This is one example of many, from my clinical practice, and it represents the amazing, unnerving logic of the body as damage wends its way, up and out from the gut, affecting various pathways, systems and organs, resulting in hundreds of diseases. What follows is my experience with food sensitivities and food allergies in terms of symptom presentation, testing, and treatment.
Food sensitivities, not to be confused with food allergies, are a common cause of irritable bowel syndrome, along with a host of other symptoms including, but not limited to, inflammation, headaches, rashes, weight gain, fatigue, and muscle soreness.
The terms “sensitivity” and “allergy” have often been used interchangeably, perpetuating confusion about the differences between the physiologic responses.
A conventional physician or allergist is unlikely to recognize food sensitivities. Within a functional medicine framework, addressing food sensitivities is essential to a gut-healing program.
Food sensitivities are delayed food reactions, generally occurring up to 72-hours after ingestion. For this reason, food sensitivities are often called delayed food reactions or food intolerances. They are the result of the slow accumulation of immunoglobin IgA and IgG, and as such, it is likely that foods recently eaten will test positive on a food sensitivity test. Additionally, the foods eaten more frequently are also more likely to test positive for sensitivity.
Food sensitivities are not life-threatening. Eliminating the inflammatory food from the diet for ninety days can resolve associated symptoms.
Food sensitivity testing involves measuring levels of the immunoglobins IgA and/or IgG antibodies in the blood. This testing is not diagnostic and has a high level of false positives for the reasons stated above. Foods that commonly test positive with testing are wheat, dairy, and corn.
A true food allergy is an immune system response due to an antibody called IgE. Symptoms of wheezing, difficulty swallowing or breathing, vomiting, or anaphylaxis can occur immediately or up to eight hours after ingestion. Food allergies are also known as immediate or Type 1 hypersensitivity. They occur most often in children and are often outgrown.
Conventional practitioners and allergists use IgE food allergy testing, although the gold standard to identify a food allergy entails eating a food and observing an individual’s reaction. This test is known as an oral food challenge. When there is a true food allergy, most commonly observed in reaction to peanuts, soy, and shellfish, the food must be avoided.
I do less food sensitivity testing than I used to. Food sensitivity testing is expensive and is often not wholly accurate. I also am less concerned, for example, when asparagus tests positive on food sensitivity testing. Asparagus is not the typical culprit of the myriad of symptoms people experience as a result of food sensitivity. More commonly, gluten and dairy are the culprits so often I recommend women try eliminating those foods first. If eliminating gluten and dairy doesn’t improve symptoms, the next step is to try a modified autoimmune protocol diet.
Don’t be thrown off by the word diet.
These food plans are not intended to be maintained forever. They are therapeutic nutrition interventions, using food as medicine. For people who choose food sensitivity testing, think of the results like a compass — information to steer by, not necessarily the final destination.
Food sensitivities and allergies can persist, if not addressed, and function as warning signs of greater health issues, up ahead. Bring your body's allergic response back under control and eliminate the symptoms from your life. They're nothing to sneeze at!