Asthma and food allergies

Foods, food additives and food chemicals are not common triggers for asthma. They rarely trigger asthma on their own, but they can do so 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 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, and a reaction can be life-threatening.

Symptoms of food allergies#

An allergic reaction to food may be mild, moderate or severe. Some of the symptoms include:

• Itching, burning and swelling around the mouth.
• Swelling of the face or eyes.
• Runny nose.
• Skin rash (eczema) or hives (urticaria – the skin becomes red and raised).
• Nausea, vomiting, diarrhea and abdominal cramps.
• Breathing difficulties, including wheezing and asthma.

Anaphylaxis#

A severe food allergy reaction is known as anaphylaxis. This is an extreme allergic reaction that can be life-threatening without prompt medical treatment. A life-saving injection of adrenaline, given through an auto-injector such as EpiPen® or Anapen® (an adrenaline autoinjector), is used to treat anaphylaxis and prevent permanent injury or death.

The onset of symptoms can be immediate (within about 2 minutes to 2 hours) or get steadily worse over time. Some symptoms of anaphylaxis include:

• Difficult or noisy breathing.
• Swelling of the tongue.
• Swelling or tightness in the throat.
• Difficulty talking or a hoarse voice.
• Wheeze or persistent cough.
• Persistent dizziness or collapse.
• Becoming 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

Intolerance to food chemicals is dose-related, which means the symptoms tend to get worse the more you eat.

Food chemicals that may trigger asthma symptoms#

Some of the food chemicals known to trigger asthma in susceptible people include:

• Sulphites and benzoates – additives widely used as preservatives and antioxidants in the food and pharmaceutical industries.
• Food colorings – such as the yellow dye tartrazine.
• Salicylates – naturally occurring in many foods, including instant coffee, soy sauce, tomatoes, tomato paste and sauce, beer, some wines and honey.

Food colorings very rarely trigger asthma attacks. Generally, if a person with asthma reacts to one food coloring, they should avoid food colorings altogether.

Read the labels on food products#

Some food additive numbers to look out for include:

• Monosodium glutamate – 621
• Benzoates – 211, 213, 216, 218
• Sulphites – 221, 222, 223, 224, 225, 228
• Tartrazine – 102

Food regulators and consumer guides publish lists of food additives and their numbers, which can help you check labels.

Identifying trigger foods#

It is important to identify the foods or food chemicals that may cause problems for you, but this must be done under strict medical supervision. Don’t try to diagnose trigger foods yourself, because you may restrict your diet unnecessarily, which can 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. If you are concerned about your diet, consult your doctor or dietitian.

Key points#

• Some symptoms of a food allergy may include nausea, vomiting, itching and swelling around the mouth, hives and breathing difficulties.
• The onset of symptoms can be immediate (within about 2 minutes to 2 hours) or get steadily worse over time.
• Some symptoms of anaphylaxis include difficult breathing, swelling of the throat or tongue, collapse, and becoming pale and floppy in young children.
• Foods that may cause an allergic reaction in susceptible people include eggs, peanuts, tree nuts, shellfish, wheat, sesame, milk, soy and lupin.
• Intolerance to food chemicals is dose-related, which means the symptoms get worse the more you eat.

Where to get help#