Food allergies, sensitivities and intolerances.
Speak to any experienced health practitioner in practice today, and they will attest to the seemingly ever-increasing prevalence of food allergies and intolerances over the last 20 years, especially in children. The Centers for Disease Control (CDC) has documented an 18% increase in the incidence of fully blown IgE food allergies in children from 1997 to 2007, and it has been estimated to now be closer to a 50% increase in the last ten years. These estimates do not include the increase in IgA and IgG-mediated food sensitivities that have been shown to precede the development of the far rarer IgE kind, often when left undetected without treatment.
Food Allergy (IgE antibody-mediated immune reaction)
It is important to note that a ‘Scratch’ test, often performed by a conventional medicine specialist, is not designed for foods. Primarily due to differences in the behaviour of various body membranes. Skin-applied antigen scratch tests are best used to investigate environmental antigens and are not the most appropriate testing method for foods. Strictly speaking, a food ‘allergy’ is considered to be a relatively immediate, IgE antibody-mediated immune reaction towards any foodborne antigens, of which affected individuals will generally be allergic to for life. Therefore, IgE antibodies to foods should be assessed via blood measurements (largely due to the transgression of food antigens being across the gastrointestinal membrane and its associated lymphoid tissue, rather than the external skin membrane), for the most accurate food allergy test results.
While anaphylaxis represents one of the most extreme and absolute examples of an allergy response to food, it should be noted that IgE antibodies tend to be formed to environmental allergens (such as moulds, pollens, dust mites, pet dander etc.) far more frequently than they are to foods.
Food Sensitivities (IgA and IgG antibody-mediated immune reaction)
Food ‘sensitivities’ typically present as relatively more subtle and delayed hypersensitivity reactions involving IgA and IgG antibody-antigen immune complexes. These antibodies attach to various offending food antigens and accumulate in different tissues around the body, causing many varied and often highly delayed symptoms (sometimes appearing up to 3-5 days after initial ingestion). Under these conditions local tissue resources and membrane defences can be compromised, thus promoting more insidious, severe vulnerabilities and responses to emerge. Assessment methods for IgA and IgG antibody responses to foods need to be far more nuanced in terms of laboratory methodology, and test results interpretation to provide accurate and efficient clinical benefits. This is often not the case and is a major concern for health practitioners.
Food Intolerances (NON-Immune related factors)
The now commonly used term food ‘intolerance’ includes all bodily reactions that arise from NON-immune related factors. These factors include enzyme deficiencies (lactose vs lactase), chemical mediators in food that precipitate inflammatory reactions (such as the amines Histamine and Tyramine) as well as excess neuro-excitation by Glutamates and detoxification impairments by Salicylates. In addition, physical gastrointestinal distress can be caused from the irritating and/or flora disrupting (especially in cases of SIBO) food additives (such as preservatives, thickeners, emulsifiers and stabilisers), each causing their own highly varied and potentially intermittent symptoms based on the metabolic sensitivity of the individual at the time, in combination with the volume and duration of exposure. Because of the scope, transience and intangibility of these intolerances’, few conclusive biomedical tests exist for them. Subsequently, the determination of these intolerances is through various forms of well monitored and recorded dietary rotation elimination programs, considered by many health practitioners to be the gold standard.
IgG Controversy & Assessment
The accuracy and validity of IgG based food sensitivity assessments has created some controversy in recent years. This is due to some of the complexities at play, including the very nature of the immune system itself, as well as the variability between lab processes, medical terminology and the intended treatment strategies.
The research commonly cited to show the inappropriate clinical use of IgG antibody testing does so based on flawed lab/test methodology and interpretation. Research has repeatedly shown that, despite its theorised role as the singularly most established food sensitivity antibody (and therefore supposedly the ‘only one worth measuring’), testing only the 4th subclass of IgG (IgG4) on its own in fact reflects less than 5% of the total IgG production in the body and appears to have ‘antiallergic’ effects. Researchers believe IgG4 to be the LEAST relevant and most counterproductive IgG antibody to measure in the assessment of food-immune precipitated symptoms and is therefore not recommended as a clinically relevant diagnostic assessment.