Food Intolerances & Allergies

What Are Food Intolerances?

Food intolerances are on the rise, it is estimated that 1 in 5 are suffering from an intolerance. Scientists say the increase cannot be explained by genetic drift9. Usually food sensitivities result from a complex combination of lifestyle, diet and environmental factors that impact the health of the gut. Food sensitivities are non-immune and mediated by IgG antibodies8 whilst food allergies are different because they are immune system related, mediated by IgE antibodies. Food allergies can be life threatening whereas intolerances can cause a host of chronic symptoms that are seemingly unrelated2.

Food Sensitivity Symptoms

  • Fatigue
  • Gas and bloating
  • Nasal congestion and sinus problems
  • Migraines or frequent headaches
  • Can’t concentrate
  • Mood swings
  • Sore or stiff joints
  • Trouble losing weight
  • Skin issues such as dry flaky skin, eczema, acne and psoriasis
  • Wheezing 
  • And more! This is why many do not realise they have a food intolerances.

Most Common Food Intolerances

Unfortunatley it is often the foods that the person is intolerant to that can be the most difficult to give up. However the good news is that once it is removed you will feel so much better it will be worth it.

Some of the most common food intolerances include:

  • Wheat & other gluten containing grains such as barely, rye, semolina and spelt.
  • Corn
  • Dairy, particularly the casein and lactose from cow’s milk including ice cream, cheese, cream however may still tolerate butter as the protein is usually removed
  • Soy, soy has a similar protein to cow’s milk however many can still tolerate
  • Yeast, in some instances people have thought they were intolerant to wheat but it was actually the yeast used to make bread.
  • Night shades such as eggplant, chillies, potatoes and tomatoes

Diagnosing Food Sensitivities

Reliable tests are now available to diagnose food sensitivities. Without a test it is difficult to diagnose food intolerances because they have a wide range of symptoms which can vary from person to person. Symptoms may include the obvious ones such as digestive issues like bloating and gas or less obvious such as skin rashes, upper respiratory issues, pain and inflammation. These issues can also be symptoms for a range of other health conditions making food sensitivities difficult to pinpoint1. Reactions to foods are often delayed by 24 – 100 hours which also makes them difficult to diagnose9.  

The Australasian Society of Clinical Immunology and Allergy state that the only way to determine a food intolerance is through an elimination diet with a qualified dietitian or doctor. However there is actually robust evidence that shows that IgG food intolerance tests work, which is detailed below.

Evidence for Food Sensitivity Tests

Despite the existing controversies with food intolerance tests, there are a number of published papers proving their effectiveness8.

A study conducted with 103 participants measured IgG antibodies for 14 food antigens to determine the relevance IgG antibody levels with those suffering from IBS-D. Antibodies were found in 50.65% of the IBD group and 15.38 in the control group. In accordance to test results foods were excluded for 12 weeks which resulted in a significant improvement with “abdominal pain (bloating level and frequency), diarrhoea frequency, abdominal distension, stool shape, general feelings of distress”4.

Another study has shown removing the offending foods improved bloating, indigestion. In yet another study done on 388 children who are allergic to wheat, had coeliac disease a Helicobacter pylori infection, or were healthy with none of those issues, the group with the highest IgG antibodies were those with a wheat allergy. The healthy children had the lowest levels of antibodies and therefore inflammation out of them all10.

IgG Food Sensitivity Tests

IgG tests are traditionally used to detect previous infections from bacteria and viruses, immunoglobulin G are the most common antibodies found in bodily fluids and they help fight off infections9.

High IgG levels in the blood has been hypothesised to be from damage to the intestinal barrier resulting in an uncontrolled immune response when food particles are released into other parts of the body5. Inflammation is caused when excessive antigens and antibodies form a complex with food particles3.

A blood spot is required for an IgG test to provide an antibody assessment on a range of foods. Higher levels of antibodies indicates an intolerance or sensitivity6. This test is available through independent labs such as Nutripath, Aust Bio Testing and RN Labs.

I have a food intolerance, now what?

Food intolerances are usually caused by leaky gut and an over abundance of unfriendly bacteria or not enough of the good ones. There can also be issues with digestion, slow transit and a lack of enzymes. There are a number of ways to tackle these issues, some of these include: 

  • Probiotics
  • Enzymes 
  • Elimination diet
  • Reducing inflammation 
  • Microbiome testing 
  • Prebiotics 
  • Fibre
  • Detoxing & cleansing the gut
  • Specific eating plan


IgG tests can be controversial however there is scientific evidence that proves they work, a reputable lab I work with Nutripath offers IgG tests which can be done after a consultation with me. If there are a large number of foods you are intolerant to considerable attention is required to improve your gut health. An elimination diet can also pinpoint food intolerances, however this can be time consuming and tedious. Significant inflammation can be caused by continual exposure to the foods you are intolerant to so it is important to remove them at least temporarily in most cases as part of your gut healing plan. Contact me today for an appointment!





  1. (2019). Food Intolerance. Australasian Society of Clinical Immunology and Allergy. Retrieved 6 February 2022, from
  2. Caminero, A., Meisel, M., Jabri, B., & Verdu, E. (2018). Mechanisms by which gut microorganisms influence food sensitivities. Nature Reviews Gastroenterology & Hepatology, 16(1), 7-18.
  3. Gocki, J., & Bartuzi, Z. (2016). Role of immunoglobulin G antibodies in diagnosis of food allergy. Advances In Dermatology And Allergology, 4, 253-256.
  4. Guo, H., Jiang, T., Wang, J., Chang, Y., Guo, H., & Zhang, W. (2012). The Value of Eliminating Foods According to Food-Specific Immunoglobulin G Antibodies in Irritable Bowel Syndrome with Diarrhoea.Journal Of International Medical Research, 40(1), 204-210.
  5. Malsagova, K., Stepanov, A., Sinitsyna, A., Izotov, A., Klyuchnikov, M., Kopylov, A., & Kaysheva, A. (2021). Determination of Specific IgG to Identify Possible Food Intolerance in Athletes Using ELISA.Data, 6(11), 122.
  6. (2021). Food Intolerances Test | IGG Food Sensitivities Allergy Testing. NutriPATH Integrative and Functional Pathology Services. Retrieved 7 February 2022, from
  7. RN Labs. (2022). Patient Pathology Request Form. RN Labs. Retrieved 7 February 2022, from
  8. Shakoor, Z., Al Faifi, A., Al Amro, B., Al Tawil, L., & Al Ohaly, R. (2016). Prevalence of IgG-mediated food intolerance among patients with allergic symptoms. Annals Of Saudi Medicine36(6), 386-390.
  9. Velikova, T., A Kukov, A. et al. (2018). Methods for detection of food intolerance. R Adv Food Sci: 1(3): 106-119 ISSN: 2601-5412 11
  10. Czaja-Bulsa, G., Bulsa, M. & Gębala, A. Food IgG4 antibodies are elevated not only in children with wheat allergy but also in children with gastrointestinal diseases. BMC Gastroenterol 16, 39 (2016).

By nutritionist Chrissy

Chrissy is a university qualified nutritionist who graduated with honours at La Trobe University in Melbourne. One of her favourite hobbies is to read the scientific literature on how to optimise health. When she’s not reading, writing or working she’s with her 3 children outdoors, practicing yoga, jogging or cooking up a storm in the kitchen. Chrissy has overcome some debilitating chronic health issues (low mood, adrenal fatigue, insomnia, very bad acne to name a few) with the power of nutrients and correcting gut health, at 39 she now feels better than she did in her 20’s.