Food Allergy or Food Intolerance?

Updated: Jul 12

Do you know the difference between food allergy and food intolerance?

The mechanism behind the two is significantly different. Food intolerances involve the digestive system, whilst food allergies involve the immune system.


Food intolerance is used to describe a wide range of adverse reactions to the consumption of some foods. People who experience food intolerances would present with symptoms from 4 domains: ⁠

  • digestive system (e.g. reflux, IBS, diarrhoea)⁠

  • skin reactions (e.g. eczema, hives, swelling)⁠

  • respiratory tract (e.g. sinus congestion, asthma, throat irritation)⁠

  • nervous system (e.g. headache, fatigue)⁠

  • Other possible symptoms: mouth ulcers, nausea and bladder irratation.⁠

Most of the time food intolerances do not caues physical harm to the body however may affect quality of life and general wellbeing.


On the other hand, Immunoglobulin E (IgE) antibody mediated food allergy, is caused by the body's immune system reacting to food upon consumption. Allergic reactions can range from mild to severe, with mild to moderate symptoms include swelling, hives, stomach pain and vomiting. Severe reactions include anaphylaxis and the heart which can be life threatening. It is unlikely adults develop food allergies in their adulthood, but if you do suspect an allergy please speak with your doctor as it can be life threatening. ⁠The gold standard test to identify food allergy is to be performed by doctors through skin testing or blood tests.




Can I test to check if I have a food intolerance?

Food intolerances are difficult to diagnose as there is currently no credible test available to perform this. According to the ASCIA (Australiasian Society of Clinical Immunology and Allergy)'s statement:

These tests include cytotoxic food testing, vega testing, kinesiology, allergy elimination techniques, iridology, pulse testing, alcat testing, Rinkel's intradermal skin testing, reflexology, hair analysis and IgG food antibody testing. Not only do these tests lack any scientific rationale, but have been shown to be inaccurate and unreliable in published studies.

How can I manage a suspected food intolerances?

The best approach is to first see your doctor to investigate the cause and make a diagnosis. One of many methods to manage food intolerances is to trial a temporary elimination diet, under the supervision of a dietitian and doctor.


Elimination diets involves removing the food group of interest for a period of time and reintroducing slowly to determine your personal threshold. Every individual's threshold of food intolerance can vary. Some elimination diets include the Low FODMAP diet for IBS, FAILSAFE / RPAH (Royal Prince Alfred Hospital) / Food chemicals elimination diet and whole foods such as dairy and gluten. You can read more about the RPAH Food Chemical Intolerance Diet here.


It is important to remember that elimination diets are temporary and should only be used as a diagnostic tool. Food chemical elimination diets can be highly restrictive and therefore require careful guidance of a dietitian to ensure you are still meeting your nutrition requirements.


Learn more about food intolerances on ASCIA's website here.


Interested in starting an elimination diet? Book an appointment with our Accredited Practising Dietitian who are experienced with managing food intolerances (incl. food chemicals and low FODMAP)