Food sensitivity testing and its link to the microbiome

All testing provides information. It is the practical application of that information in relation to symptoms that is the key to success. Food sensitivity testing gives clients clinically meaningful results (1) about which foods eaten are stimulating an immune response and potentially contributing to symptoms. This is measured by the number of IgG antibodies raised to individual foods. 

IgG antibody stimulation is a normal process of the immune system as it ‘tests’ the proteins or epitopes on the surface of molecules. IgG antibodies signal to the immune system that this food, or protein chain, is either safe or potentially problematic, initiating a chemical cascade. Symptoms arise when individual foods raise a significantly high number of IgG antibodies which build complexes with the food proteins. If these complexes build up faster than the body can do its normal housekeeping job of breaking them down, they may lodge in tissues and may contribute towards inflammation and other food sensitivity symptoms.   

The immune system is complex and difficult to treat conditions, such as irritable bowel syndrome (2) and migraine (3), have been directly attributed to food sensitivity delayed immune reactions. Eliminating foods following IgG food sensitivity testing may result in an improvement in difficult to resolve symptoms, in this trial a 75.8% symptom improvement was demonstrated in 5,286 subjects displaying a wide range of chronic medical conditions (4).

So where does the link to the immune system and microbiome fit?

Ideally, we shouldn’t be responding to any foods that we eat, but our ability to distinguish friend from foe is breaking down. Our intestinal epithelial barrier (IEP) should be intact, only allowing access to the body to foods digested into their smallest constituent parts, such as free amino acids or small amino acid trains (peptides). However, where there is disturbance to the integrity of the IEP due to active infection, stress, poor diet, excess alcohol consumption, medications (5), age, smoking, etc, disruption to the microbiome occurs and intestinal permeability (IP), or leaky gut, may occur.  Our gut microbes are highly responsive to even minor changes to diet and lifestyle. 

Leaky gut allows partially digested food molecules free access to our systemic circulation (6). The immune system, always on surveillance, will detect these larger food molecules stimulating an immune response which is reflected in a food sensitivity test. The higher the number of foods elevated on a report the more likely leaky gut is present. Food sensitivities can both be a contributory cause of symptoms and a result of the damage to the IEP which precedes leaky gut (7). 

The simplest way to restore intestinal permeability and the microbiota (the term used to describe the combination of all microorganism species colonising the gut) could be ideal nutrition (8) and food choices. Ideal nutrition includes eliminating or reducing those foods in the diet that stimulate a detrimental immune response, drive inflammation, and feed the dysbiotic (or non-beneficial) bacteria. These foods, bespoke to every individual, may be highlighted in a FoodPrint food sensitivity test. Testing removes the guesswork and can inform dietary decisions from the outset.