Australia has one of the highest allergy rates in the world. Food allergy affects 1 in 10 infants and about 2 in 100 adults in Australia and can be genetic. Food intolerance is even more common with surveys indicating that up to 25% of the population believe they have a food intolerance. A food allergy is a reaction that occurs when the immune system incorrectly attacks components of food, treating it as foreign invader. This exaggerated immune response leads to a variety of symptoms, and in severe cases, the immune response can be so aggressive that it can lead to life-threatening anaphylaxis. 

Unlike allergies, food intolerances do not involve an aggressive immune response and are generally not as severe as an allergic reaction. Nevertheless, food intolerances can still severely impact your quality of life. A food intolerance response takes place in the digestive system and occurs when you are unable to properly break down components of food, due to enzyme deficiencies, sensitivity to food additives or reactions to naturally occurring chemicals in foods. Bloating, flatulence, diarrhea, irritable bowel and abdominal pain are common among food intolerance reactions.1 

Is coeliac disease an allergy or intolerance? 

Coeliac disease is not an allergy or intolerance, even though it involves the immune system. Instead, coeliac disease is an autoimmune disorder, where a reaction is initiated from a complex inflammatory response triggered by gluten consumption in genetically predisposed people.2 People with coeliac disease are not at risk of anaphylaxis, but can experience symptoms of nausea, diarrhea, abdominal pain and malnutrition.  
Non-coeliac gluten sensitivity is a recently recognised condition which can cause symptoms of digestive disturbance such as bloating, malaise and tiredness, in the absence of celiac disease and wheat allergy. The mechanism is currently unknown and diagnosis is presently confirmed by gluten withdrawal and challenge protocols.3  
 
Diagnosis and management of food intolerances 

Symptoms of food intolerance can be vague, making them difficult to diagnose. Much of the time, the quantity or dose of foods eaten can dictate the frequency and severity of symptoms. The best approach is to gain a correct diagnosis, through eliminating other conditions which may be causing the symptoms, identifying if diet or other factors play a role, and classifying individual triggers.4 Once a diagnosis is made, a clinical history may help identify the role of diet or other factors that make symptoms worse, such as stress or altered eating habits.  
 
Steps to support the management of food intolerances;4 

• Identification of intolerance through clinical history and food/ symptom diary 
• Remove or limit intake of known intolerance 
• Address underlying digestive concerns which may be contributing to intolerance  
• Elimination and challenge diet to identify the intolerance and its tolerable level 
• Exclusion diets such as the low FODMAP diet are intended for short term use and should be conducted under the guidance of a health professional  
• Improve stress management and identify other factors that may play a role  

 
1. https://www.allergy.org.au/patients/food-other-adverse-reactions/food-intolerance 
2. Barbaro, M. R., Cremon, C., Stanghellini, V., & Barbara, G. (2018). Recent advances in understanding non-celiac gluten sensitivity. F1000Research, 7, F1000 Faculty Rev-1631. https://doi.org/10.12688/f1000research.15849.1  
3. Soares, R. L. S. (2018). Irritable bowel syndrome, food intolerance and non-celiac gluten sensitivity. A new clinical challenge. Arquivos de gastroenterologia, 55, 417-422. 
4. Lomer, M. C. E. (2015). The aetiology, diagnosis, mechanisms and clinical evidence for food intolerance. Alimentary pharmacology & therapeutics, 41(3), 262-275.