”Some people can’t eat gluten for medical reasons, which that I get. It annoys me but I get it. But a lot of people don’t eat gluten because somebody in their yoga class told them not to.” – Jimmy Kimmel
Australia has one of the highest prevalences of allergies in the world, and food intolerances are believed to be even more common. So what is the real difference between a food allergy and intolerance?
A food intolerance is a reproducible adverse reaction to ingested food that is not directly caused by some sort of immune dysfunction. These occur when the body is deficient of an enzyme (eg. lactase to digest lactose) or has a reaction to substances found in food.
Common causes for food intolerances include: dairy products, eggs, flavour enhancers such as monosodium glutamate (MSG), food additives, strawberries, citrus fruits, tomatoes, some wines, histamines and other amines in some foods.
Some symptoms of a food intolerance are similar to those of allergies. For example: both may display itching of the skin, diarrhoea, breathing problems and other allergy-like symptoms. However food intolerances may also display symptoms such as tremors, palpitations, headaches and migraines.
A food allergy is an abnormal immune reaction to a food component, usually a protein. The degree of severity of the reaction can vary, depending on the person.
When the allergen enters the body the immune system secretes defensive immune cells, producing antibodies called immunoglobulin E (IgE). These antibodies travel to the cells that release the chemicals, hence leading to an allergic reaction. Although the ingested allergen is not harmful to all people, in a person with an allergy the body “thinks” that these allergens are something more sinister such as a bad bacteria and treats them with hostility.
Unlike a food intolerance, the ingestion of a food allergen can have minor or serious consequences. In different people different responses to allergens occur. These include: hives, skin rash, itchiness, upset stomach, nausea, swelling of the throat, vomiting, breathing difficulties, wheezing, asthma, convulsions, anaphylactic shock, death.
Table 1: Major serious Allergens (MSA)
|“Big 8” – 90% of allergies||“Second 8”|
|Sesame seedsSunflower seedsCotton seedsPoppy seeds
Severe allergic reactions may cause anaphylaxis, which if untreated, can be fatal. If exposed to an allergen, a person with anaphylaxis can have a life-threatening reaction within minutes. This includes symptoms such as: difficulty breathing, wheezing, swelling of the tongue and throat, difficulty speaking and dizziness or collapse. It is essential that people having an anaphylactic reaction receive an injection of adrenaline as well as urgent medical attention.
Food labelling, allergies and intolerances
The Australian Food Standards Code makes it easier for people with allergies to identify potential allergens within foods. The code requires the labelling of certain foods such as eggs, nuts, fish, sulphites and associated products. Understanding how to read a food label may be a useful tool for people diagnosed with a food allergy or intolerance.
If you would like more information on allergies and intolerances, you can find some great resources here. If you want specific dietary recommendations for an allergy or intolerance, please see an Accredited Practicing Dietitian.