Food Sensitivities
Food sensitivities are different from food allergies. An allergy produces an immediate immune response, usually within minutes. A sensitivity produces a delayed reaction, sometimes 24 to 72 hours after eating the food, which makes the connection between cause and symptom nearly impossible to see without testing. The symptom, whether it is bloating, fatigue, headaches, joint pain, brain fog, or a skin flare, appears long after the food is gone.
Three types of food reactions
Immediate allergy.
Mediated by IgE antibodies. Produces rapid, often dramatic reactions: hives, throat tightening, anaphylaxis. Tested by standard allergy testing. This is the type most people picture when they hear food allergy.
Delayed sensitivity.
Mediated by IgG antibodies. Produces symptoms hours to days after eating the food. This is what most people mean when they say they have a food sensitivity. Standard allergy testing does not catch it. A separate IgG food panel is required.
Fermentation intolerance.
Not an immune reaction at all. Certain carbohydrates, particularly those in the FODMAP category, are fermented by gut bacteria and produce gas, bloating, and bowel changes. This is more a microbiome issue than an immune one, and the intervention is different from treating an antibody-driven sensitivity.
How we identify them
An IgG food panel identifies delayed immune reactions to a broad range of foods. This narrows the field considerably. An elimination protocol removes the identified foods for four to six weeks and then reintroduces them systematically to confirm reactions. Our four-day food log, which you complete as part of the functional medicine intake, often reveals patterns that point toward specific foods before testing. Read more about the food log.
For people with suspected gluten sensitivity or celiac risk, we also use testing that distinguishes between the two, since they involve different mechanisms and different long-term implications.
Why it matters beyond digestion
Food sensitivities drive systemic inflammation. That inflammation shows up far from the gut: in joint pain, skin conditions, headaches, fatigue, and brain fog. People who spend years managing these symptoms without identifying the dietary drivers often find significant improvement when the sensitivities are found and removed. The gut lining usually also needs repair, since leaky gut is both a cause and a consequence of ongoing food sensitivity.
Common questions
Is there a simple blood test for food sensitivities?
An IgG food panel is a blood test, yes. It is not offered in standard medicine because IgG antibody presence does not always correlate with clinically meaningful reactions. In a functional medicine context, it is used as a starting point for an elimination protocol, not as a definitive answer in isolation.
Do I have to give up those foods forever?
Not always. Many food sensitivities develop because the gut lining is compromised. When the gut is repaired and the food is removed long enough for the immune response to quiet down, some people can reintroduce foods that previously caused reactions without symptoms returning.
Is gluten sensitivity the same as celiac disease?
No. Celiac is an autoimmune condition with structural gut damage and specific antibodies. Non-celiac gluten sensitivity produces symptoms without that structural damage. The mechanism differs, the testing differs, and the long-term implications differ. We distinguish between them.
Related: Gut health and leaky gut, IBS and SIBO, chronic inflammation
Schedule a consultation or call 704-663-2010.
