Not all food reactions are allergies, and not all food sensitivity tests measure the same thing. Understanding which immune pathway is involved changes the clinical approach entirely.
Most people have heard of food allergies. Fewer understand food sensitivities — or why the distinction matters for their symptoms.
The inflammatory cascade connecting food to systemic complaints
Certain foods — particularly those eaten daily — can provoke IgG antibody production when gut barrier integrity is compromised. Gluten, dairy, eggs, and soy are the most common in a European diet.
When the gut lining is inflamed or permeable ("leaky gut"), partially digested food particles cross into the bloodstream and trigger immune responses they would not trigger in a healthy, intact gut.
IgG antibodies bind to food antigens in the bloodstream, forming immune complexes. These activate complement pathways and drive systemic inflammation — affecting joints, skin, brain, and gut simultaneously.
Because the inflammation is systemic and delayed, symptoms appear far removed in time and site from the food trigger. Brain fog, fatigue, joint pain, and skin conditions are common presentations.
Food sensitivity and intestinal permeability reinforce each other. Ongoing reactivity drives gut inflammation, which worsens permeability, which increases antigen exposure. Breaking the cycle requires both elimination and gut repair.
Unlike IgE allergies, IgG-mediated sensitivities frequently resolve with a structured elimination protocol and gut repair programme. Reintroduction after 3–6 months is often successful for previously reactive foods.
Two validated options — each with a distinct clinical place
The IgG Food MAP from Mosaic Diagnostics (formerly Great Plains Laboratory), accessed via Regenerus Labs, is the food sensitivity test I have used most consistently in clinical practice. It measures IgG antibody reactivity across all four IgG subclasses (1–4) — a level of specificity that many cheaper panels do not offer.
The panel covers over 190 food antigens across grains, dairy, meats, fish, eggs, nuts, vegetables, fruits, herbs, and spices. Critically, it includes a Candida antigen, which I find clinically useful given the overlap between gut dysbiosis and food reactivity patterns.
This test forms the food sensitivity component of the TDG Five-Test Programme, interpreted alongside GI-MAP (for the gut microbiome picture), DUTCH Plus (for stress-hormone driven gut permeability), and Organic Acids (for dysbiosis metabolites). The combination allows patterns to be understood systemically rather than in isolation.
HealthBeings offer a range of functional health tests including an Advanced Gut Health Test (GI Axis Advanced) — a 16S microbiome sequencing panel covering 10 gut axes, 20 health insights, and a personalised nutrition plan across 52 pages of reporting. This is a stool microbiome test, not a food sensitivity test, and is more analogous to the GI-MAP than to the IgG Food MAP.
HealthBeings may also offer food reactivity panels — I am in the process of reviewing their current food sensitivity testing options and will update this page with a confirmed comparison once the panel specification has been verified. If you would like to discuss which food sensitivity test is appropriate for your clinical picture, the discovery call is the right place for that conversation.
In the meantime, the IgG Food MAP via Mosaic Diagnostics and Regenerus Labs remains my primary food sensitivity test within the TDG Five-Test Programme.
Presentations where IgG Food MAP adds genuine clinical value
| Clinical Scenario | IgG Food MAP | Notes |
|---|---|---|
| Running full TDG Five-Test Programme | ✓ First choice | Possible alternative |
| Pure delayed-onset gut and fatigue symptoms | ✓ Ideal | Suitable |
| Atopic eczema / allergic rhinitis / asthma | IgG component only | ✓ Superior — captures IgE |
| Suspected mast cell activation | Partial picture | ✓ First choice |
| Histamine intolerance workup | Useful | ✓ More complete |
| Mixed immediate + delayed reactions reported | Misses IgE | ✓ Designed for this |
| Wants broadest food antigen coverage (190+) | ✓ 190+ antigens | 120 antigens |
| Includes Candida antigen testing | ✓ Included | Not standard |
| Budget-conscious — single draw, dual value | IgG only per draw | ✓ Two pathways, one draw |
I will be direct about where IgG testing sits in the evidence landscape: the scientific literature on IgG food sensitivity testing is contested. Some researchers argue that elevated IgG antibodies represent normal immune exposure to foods rather than pathological sensitivity. This is a legitimate position and I do not dismiss it.
My clinical experience over 37 years is that IgG-guided elimination protocols — particularly when run alongside gut repair and restesting — produce meaningful, sustained improvement in a significant proportion of clients with chronic gut, fatigue, joint, skin, and cognitive presentations where conventional investigation has been unrevealing. I have seen this pattern too many times to disregard it.
IgG food sensitivity data is not used in isolation. It is interpreted alongside the GI-MAP (gut microbiome and pathogen data), Organic Acids Test (dysbiosis metabolites and mitochondrial markers), and DUTCH Plus (stress hormones and their impact on gut barrier function). A client with elevated IgG reactivity to 30 foods, a dysbiotic microbiome on GI-MAP, and elevated cortisol and zonulin is showing a coherent systemic picture — the food reactivity is a downstream consequence of intestinal permeability, not a random finding.
The test identifies the list. The clinical work is in the protocol design: phased elimination, nutritional adequacy of the exclusion diet, gut repair alongside the elimination, and structured reintroduction after 3–6 months. This is where the interpretation and support I provide actually matters. A test without a protocol is just a list of foods to feel anxious about.
Where the HealthBeings panel identifies IgE reactivity, the clinical response is different and more serious. Significant IgE elevations to a food — particularly in a client with atopic history — may warrant referral to an allergist for formal challenge testing. I am clear with clients about this distinction: IgE findings from functional testing are not a substitute for medical allergy assessment and, where indicated, I will refer accordingly.
Book a free discovery call to discuss whether food sensitivity testing belongs in your clinical workup.
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