Food allergies and intolerances are becoming increasingly more prevalent in Australia, with more than 20% of people in industrialised countries suffering from food allergies or intolerances.

In some instances, the link between a food sensitivity and health issues is not always obvious but research is finding that the effects on health can be far-reaching and, in some instances, debilitating.

The difference between food allergies and intolerances

An allergic reaction occurs when a person’s immune system responds to foods that are normally well-tolerated by others. Allergy antibodies are produced, which are proteins in the immune system that identify and react with substances perceived to be foreign, and symptoms develop within 30 minutes to 2 hours.

Common allergens: cow’s milk, peanut, soy, wheat, fish, shellfish, and eggs.

Food intolerance is more of a chemical reaction; it may involve an inability to digest food due to a non-immunological cause, for example an enzyme deficiency as found in lactose intolerance whereby there is a lack of lactase to digest the sugar, lactose.

Common intolerances: lactose, gluten, fructose, artificial additives, amines, salicylates, fodmaps, sulphites and histamines.

Possible Symptoms

Adverse food reactions can manifest in a wide range of symptoms with some of the common ones being:

  • Anaphylaxis (food allergies)
  • Gastrointestinal symptoms such as IBS, diarrhoea or constipation
  • Skin issues such as eczema or hives
  • Respiratory issues such as asthma, runny nose or sneezing.
  • Lethargy or sleepiness
  • Migraines or headaches
  • Cognitive dysfunction
  • Mood disorders such as anxiety and/or depression

Some people tolerate unwanted symptoms without realising that the food they’re eating, often the very foods they crave, are causing their health issues.

Underlying or contributory factors?
These adverse food reactions may be connected to an overall poor diet, altered microbiome, increased gut permeability and/or immune dysfunction.

Diet plays a role in food reactions; generally, a lower nutrient-dense diet and/or refined, processed diet creates more inflammation in the body, damages the immune system and adversely impacts the gut and its microbiome, leading to increased sensitivity to different foods.

Altered microbiome
Studies have shown that the microbiome or gut bacteria play an important role in food allergies with the composition of allergic people differing to that of healthy people. Regardless of country of residence, allergic children had less of the healthy lactobacilli and higher counts of the less-desirable bacteria, particularly enterobacteriaceae and staphylococci.

Increased intestinal permeability/leaky gut
Increased intestinal permeability or leaky gut has been implicated in food allergies and food intolerances and is also influenced by an altered microbiome. In one study, when IBS patients with suspected food intolerances were exposed to food antigens, intestinal permeability increased significantly; interestingly, the longer they remained on an exclusion diet the more their IBS symptoms abated.

Immune dysfunction
With more than 70% of our immune system housed in our gut, when it fails to recognise food as friend or foe, there is a loss of immune tolerance to this substance and the body reacts.

Other reasons why food reactions may be rising:

  • Hygiene Hypothesis: the theory is that basically our clean homes and cleaner living doesn’t provide the right environment for a child’s immune system to be challenged by germs and to develop properly.
  • The delayed introduction of allergenic foods to a toddler.
  • The sharp increase in refined foods in children’s diets over the last 40/50 years.
  • The tendency to have the same favourite food groups repeatedly in just one day; for example, toast for breakfast, muffin or biscuit for morning tea, sandwich for lunch, crackers for afternoon tea and pasta for dinner…that’s 5-serves of wheat which your body isn’t designed to eat!

What should you do if you have or suspect you have a food allergies or food intolerances?

Whilst some food allergies or intolerances may be managed by avoiding the offending food, it may still be important to address any underlying or contributory factors. Specifically, you might need to:

  1. Have your diet reviewed to make sure that you’re not missing out on valuable nutrients.
  2. Obtain symptomatic relief as required.
  3. Get your gut health assessed to improve gut barrier integrity and microbiome diversity.
  4. Consider your immunity and any inflammation.
  5. Evaluate if testing is necessary.

If you would like help in managing your food allergies or intolerances and you’d like to work with a nutritionist, please contact me to make an appointment.


Australian Society of Clinical Immunology and Allergy

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Fritscher-Ravens et al, Confocal Endomicroscopy Shows Food-Associated Changes in the Intestinal Mucosa of Patients with Irritable Bowel Syndrome

Myles IA. Fast food fever: reviewing the impacts of the Western diet on immunity. Nutr J. 2014;13:61. Published 2014 Jun 17. doi:10.1186/1475-2891-13-61

 Rapin JR, Wiernsperger N. Possible links between intestinal permeability and food processing: A potential therapeutic niche for glutamine. Clinics (Sao Paulo). 2010;65(6):635-643. doi:10.1590/S1807-59322010000600012

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