Is Food Allergy Testing Really the Answer?

In alternative healthcare, food allergy panels are routinely ordered. An estimated 20% of the world believes it reacts adversely to specific foods (1), while as many as 15 million Americans suffer from food allergies (2).

Food reaction can be non-immune mediated, as in food intolerance or sensitivity, or immune mediated, as in food allergy, but there is confusion even among the medical establishment. Alternative food allergy tests usually measure serum IgG antibodies, while conventional allergy tests measure serum IgE antibodies.

Do IgG Antibodies Really Identify Food Intolerance or Sensitivity?

IgG antibodies represent a delayed as opposed to an immediate, immune-mediated food reaction (IgE), and are purported by some, though scientific evidence is scant (3), to identify food intolerance or sensitivity.

How can an immune-mediated food allergy test measure something that is non-immune mediated, such as an enzyme deficiency? And is the $300 to $700 of an IgG food intolerance panel worth the cost?

While Cyrex is the most well-known food allergy lab, Great Plains Laboratory and US Biotek are also reputable. While many alternative practitioners pay lip service to root-cause medicine, food allergy panels may reveal food reactivities which are more symptom than etiology.

Are Dietary Restrictions Revealed by Food Intolerance Testing Possible to Follow?

Routinely revealing long lists of common foods to which a person is producing high serum antibody loads (titers), patients are often placed on ultra-restrictive diets, such as low-FODMAPS (4), which can be difficult to follow, induce stress, and produce low compliance.

The question is: Why are IgG levels high for these specific foods? The answer seems to lie in increased intestinal permeability.

Increased Intestinal Permeability

The immune system, merely doing its job, generates antibody labels to all foods consumed, and because these now-offending foods are crossing the gut barrier into the bloodstream, it’s working overtime. Trained to attack any invader, the immune system begins to recognize the offending foods as antigens. Later on, overwhelmed by constant vigilance and hyperactivity, the body is triggered to begin attacking its own tissues (autoimmunity), as seen in Celiac disease where gliadin antibodies attack the intestinal lining. (5)

Antibody titers will be highest, naturally, to foods consumed most often and in the greatest quantities. When these foods are dietarily removed, antibody titers to said foods gradually lower and disappear. This is why testing for tissue transglutaminase auto-antibodies (tTG-IgA) in Celiac disease, e.g., must be done before going gluten-free. (6)

Leaky Gut, Gliadin Fractions in Gluten, and Zonulin

Increased intestinal permeability, aka leaky gut, will naturally increase food reactivity, and recent research indicates that gluten plays a key role. Gliadin fractions in gluten upregulate the protein zonulin which modulates gut mucosal barrier activity, thereby causing intercellular epithelial gap junctions to expand and produce leaky gut in the intestinal lining. (7) Bad gut bacteria or SIBO can also cause leaky gut, which can lead to metabolic endotoxemia. (8) Higher systemic inflammation results, measured by biomarkers, such as hs-CRP. (9)

The Physiology of the Intestinal Lining in the Small Intestine

The epithelial lining of the small intestine is like a cheesecloth one cell layer thick, just beneath which lies connective tissue called lamina propria. (10) When this cheesecloth stretches out, undigested food particles move from the lumen (tubular inside) of the small intestine into the bloodstream. (11)

When this cheesecloth tears, it takes 3 to 7 days for it to heal, during which many food stuffs supposed to be digesting end up permeating through the intestinal lining and ending up in the blood. (12) A slight degree of intestinal permeability is supposed to be happening, as this is the immune system’s way of sampling what is being eaten, to be on the lookout for infectious organisms. But when too much occurs, autoimmune disease can develop.

Attached to the GI tract’s epithelial cells are microvilli, finger-like projections that increase the surface area of the intestines and absorb vital nutrients, fatty acids, and glycerol from food. Interestingly, tiny arteries (arterioles) go to the top of each microvilli, and tiny veins (venules) go down. (An artery carries blood to something, whereas a vein carries blood away from something.) (13)

In the middle of these arterioles and venules are lymphatic capillaries (lacteals) which absorb dietary fats taken in through the microvilli. So, basically the microvilli and epithelial intestinal lining have a blood supply their own, which nourishes and regenerates them. These microvilli are also sloughed off every 7 days, but only pieces at a time. This is why a large portion of our fecal matter is made of dead skin-like tissue, such as sloughed microvilli. (14)

The Role of Stress in the Absorption of Nutrients in the Small Intestine

At the microvilli base is an A-V shunt or connection, that’s supposed to stay closed. But when it opens, blood naturally shunts across. If this is occurring, then the microvilli will not have the required blood supply and so they will be sloughed off, inducing temporary malabsorption syndrome. Without properly functioning microvilli, zero nutrient absorption will occur, and this can last up to a few days, or be chronic. (15)

Two hormones in particular will naturally open the A-V shunt. These are epinephrine (adrenaline) and norepinephrine, which are released during fight or flight. Chronic stress will cause the adrenal medullae to release these stress hormones into the blood, inducing malabsorption and causing energy levels to plummet. (16)

The Real Cause(s) of Food Intolerance/Sensitivity and Allergy

While following the restrictive recommendations gleaned from food allergy panels may lower or resolve some chronic symptoms initially or temporarily, the jury is still out as to whether they are financially feasible or lifestyle-amenable. There is growing evidence that increased intestinal permeability (17,18,19) and subsequent low-level, systemic inflammation, due to a compromised microbiome, the consumption of excess amounts of wheat, and chronic stress, needs to be addressed in order to resolve food allergies, particularly of the delayed IgG variety. Of course, ultimately it’s up to the patient and to their healthcare practitioner.

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