About asthma and food allergies
Foods, food additives and chemicals are not common triggers for asthma. They rarely trigger asthma by themselves, but can trigger asthma either as part of a food allergy or an intolerance reaction.
An allergy is when the body’s immune system overreacts to a substance that is normally harmless to most people. These substances are also known as allergens. Being exposed to an allergen may cause irritation or swelling in areas of the body such as the nose, eyes, lungs, air passages and skin.
A severe food allergy reaction is known as anaphylaxis and can be life-threatening.
Symptoms of food allergies
An allergic reaction to food may be mild, moderate or severe. Some of the symptoms may include:
- itching, burning and swelling around the mouth
- swelling of face or eyes
- runny nose
- skin rash (eczema)
- hives (urticaria – skin becomes red and raised)
- diarrhoea
- abdominal cramps
- breathing difficulties, including wheezing and asthma
- vomiting
- nausea.
Anaphylaxis is potentially life threatening
An anaphylactic reaction, or anaphylaxis, is an extreme allergic reaction that can be life threatening without prompt medical treatment. A life-saving injection of adrenaline, administered through an auto-injector such as EpiPen® or Anapen® (also known as an adrenaline autoinjector), is required to treat anaphylaxis to prevent permanent injury or death.
The onset of symptoms can occur immediately (within 2 minutes to 2 hours) or steadily get worse over time.
Some of the symptoms of anaphylaxis include:
- difficult or noisy breathing
- swelling of tongue
- swelling or tightness in the throat
- difficulty talking or hoarse voice
- wheeze or persistent cough
- persistent dizziness or collapse
- pale and floppy (in young children).
High-risk foods that may cause allergies
Some of the foods that may cause an allergic reaction in susceptible people include:
- eggs
- peanuts
- tree nuts
- shellfish
- wheat
- sesame
- milk
- soy
- lupin.
Food chemicals that may cause asthma
Intolerance to food chemicals is dose-related, which means the symptoms get worse the more you eat.
Some of the food chemicals that are known to trigger asthma in susceptible people include:
- sulphites – these additives are widely used as preservatives and antioxidants in the food and pharmaceutical industries
- food colourings – such as the yellow food dye tartrazine. Food colourings very rarely trigger asthma attacks. Generally, if a person with asthma reacts to one food colouring, they should make sure to avoid eating any food colourings
- monosodium glutamate (MSG) – this is a naturally occurring chemical, frequently used as an additive to enhance flavour, particularly in savoury snack foods. Foods that contain high concentrations of MSG include stock cubes, gravy, soy sauce and packet soups. Hydrolysed vegetable protein is sometimes added to foods in place of MSG, and may trigger asthma in people who are sensitive to MSG
- salicylates – naturally occurring salicylates are also present in many foods, including instant coffee, soy sauce, tomatoes, tomato paste and sauce, beer, some wines and honey.
Read the labels on food products
Some food additive numbers to remember include:
- benzoates – 211, 213, 216, 218
- sulphites – 221, 222, 223, 224, 225, 228
- tartrazine – 102
- monosodium glutamate – 621.
If you are looking for more information, you could check the Official Shopper’s Guide to Food Additives and Labels, which is available through libraries, major bookshops, supermarkets and newsagencies. Food Standards Australia New Zealand (FSANZ) also has a list of food additives and their numbers on their website.
Identifying trigger foods
It is important to identify the foods or food chemicals that may cause problems for you.
This must be done under strict medical supervision. Don’t try and diagnose the trigger foods yourself, because you may restrict your diet unnecessarily and this may be unhealthy. For example, some people with asthma avoid dairy products because they believe (incorrectly) that these foods cause an overproduction of mucus in the airways.
Your doctor or allergy specialist may conduct a blood test or skin prick test to determine your allergies. Sometimes they will eliminate a food and compare lung function tests before and after elimination.
No special asthma diet
Only a small percentage of people (less than 3 in 100) with asthma have food allergies or intolerances that trigger asthma flare ups.
It is important to remember that no foods either cause or prevent asthma.
Like anyone else, people with asthma should eat a healthy, balanced diet that includes plenty of fresh and unprocessed foods, particularly fruit and vegetables. If you are concerned about your diet, consult with your doctor or dietitian.
Where to get help
- Your GP (doctor)
- Respiratory physician
- Allergy specialist (your doctor can refer you)
- Dietitian
- The Royal Children's Hospital has produced a number of videos to help you better understand and manage your child's asthma.
- Asthma Australia Tel. 1800 278 462
- National Asthma Council Australia
- Australasian Society of Clinical Immunology and Allergy (ASCIA)
- Allergy & Anaphylaxis Australia. Tel. 1300 728 000
