Do You Have a Food Intolerance? Here’s How To Find Out.

Food sensitivities, intolerances or allergies can be a difficult road to navigate when we are on the path to improving our health. Particularly when we are suffering from chronic symptoms and ongoing digestive complaints, we might feel like we are reacting to anything and everything we eat, leaving us confused, frustrated and unsure of where to start. Let’s firstly understand what the differences are.

  • Food Allergy: A known food allergy will usually result in an immediate and intense even life-threatening reaction, such as anaphylaxis. Typical foods here are peanuts and shellfish.
  • Food Sensitivity: Possible immunologic reaction to food, mediated by slower responding IgA or IgG antibodies. There can be delayed hypersensitivity to certain foods in this instance, therefore symptom onset may also be delayed and difficult to track. Sensitivity to eggs can be a common food sensitivity.
  • Food Intolerance: Typically, a non-immunologic (not involving the immune system) reaction to food. Lactose intolerance is one of the most common examples here.


Food intolerance and sensitivity symptoms can often be as varied as they are unknown. Examples of some common symptoms include headaches, fatigue, migraines, mood changes, brain fog, nasal congestion, bloating, skin complaints or joint pain. A protein such as gluten can produce incredibly debilitating symptoms when eaten by a coeliac, however a non-coeliac may still experience gluten intolerance symptoms (even subtly) following consumption such as abdominal pain, constipation or diarrhoea or a feeling of general tiredness.


Food allergy testing – Doctors and immunologists will conduct IgE blood testing to determine IgE mediated allergies.

Food sensitivity testing – Through serum (or blood spot) testing the Immunoglobulin responses (IgG or IgA) can be used to identify potential reactive foods. IgG food sensitivity is triggered by the binding of compliment to IgG food antigen complexes, causing an inflammatory response. Note – be aware of the many different options of this type of testing available on the market and where quality standards of testing methods and the practitioner utilising and interpreting results is of utmost importance.

Food intolerance testing – Often through food challenging and/or elimination, ideally under the guidance of a practitioner. An example of Lactose intolerance testing is the hydrogen breath test. Common dietary sugars such as lactose are normally absorbed in the small intestine. If not completely absorbed, they may pass into the large intestine where they are consequently fermented by bacteria and produce hydrogen and other associated gases.

If you have a known food allergy, intolerance, or sensitivity a holistic management plan is vital for your overall health. This includes adequate whole food inclusions or replacements if you must avoid a particular food or foods for a period time. Investigations into correlating digestive issues or metabolic problems is incredibly important as such factors are often underlying drivers of immune responses to foods, particularly if associated symptoms are increasing in severity or chronicity. Employing the guidance of a skilled practitioner can assist in identifying underlying causes of food sensitivities and intolerances and support short term elimination diets if necessary and most importantly long-term dietary planning, to ensure foods are not unnecessarily restricted.

Listening to the signs and signals our body is sending us, is one way to begin to support ourselves better in navigating how we are responding to food. Bloating after eating is one of the most common complaints and so I recommend a dietary recall including things such as what you ate in the meal, how you felt when you were eating (e.g., stressed, relaxed, irritable), were you sitting down or on the run, do you usually avoid this food and so on. These are some questions we can begin to ask ourselves and can help provide insights into what may be triggering our symptoms. 

So often we may be experiencing symptoms that cannot be attributed to one food, but more so the whole spectrum of digestive processes needed to digest our food. We may have underlying leaky gut (intestinal permeability), SIBO, pathogens, gallbladder and bile  insufficiency, auto-immunity or even thyroid issues that could be contributing to our symptoms and require adequate support and management. Food sensitivities and intolerances are only one piece to the health puzzle, and so often are a valuable sign to invite us to look deeper and from an all-encompassing body systems perspective. 


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