Diet of Elimination

Food intolerance and food allergy are often confused because the symptoms of food intolerance can resemble the symptoms of food allergy.

However, food intolerance does not involve the immune system and does not cause severe allergic reactions known as anaphylaxis.

A food allergy occurs when the immune system reacts to a food.  Food intolerance occurs when the body has a chemical reaction to eating a particular food or drink.  Food intolerance does not show on allergy testing and this can make finding the foods that cause the problems more difficult at times. A diet of elimination is helpful in these cases.

Food intolerance can be difficult to understand and is poorly understood by doctors and dieticians as well.  Sometimes the substances in foods can increase the frequency and severity of migraine headaches, produce rashes or hives or affect the bowel and upset the stomach. As we spend many hours eating and drinking a wide variety of food and drink, determining the actual cause of the symptoms can be confusing.


It can be difficult to tell the difference between the symptoms of food allergy and food intolerance.

Usually, symptoms caused by a true food allergy develop very soon after eating the food.

The symptoms of food intolerance can also be immediate, but may also take 12 -24 hours to develop.


Symptoms of Food Intolerance

Some symptoms of food intolerance can include:

  • Headache or migraine
  • Sweating and palpitations
  • Hives or rash
  • Diarrhoea
  • Bowel cramping and pain
  • Allergy-like reactions
  • Rapid breathing
  • Burning sensations on the skin

Symptoms of Food Allergy

The symptoms of a true food allergy can be life threatening. Common symptoms include:

  • Anaphylaxis
  • Burning, itching and swelling around the mouth and tongue
  • Urticaria (skin hives that are raised and red)
  • Abdominal cramps
  • Diarrhoea
  • Breathing difficulties
  • Wheezing
  • Asthma
  • Nausea and vomiting

Various areas of the body can be affected by food allergy such as:

  • Eyes – itchy and watering
  • Nose – stuffiness and sneezing
  • Lungs – wheezing, coughing and asthma
  • Throat – swelling
  • Mouth – swelling and itching
  • Digestive system – Stomach pain and cramps, diarrhoea and vomiting
  • Skin – rashes, hives
  • Central nervous system – headache, fatigue and convulsions

Anaphylactic Shock

Anaphylactic shock is life threatening. It is a severe allergic reaction that needs urgent medical attention. The most common allergens that cause anaphylaxis are foods, (peanuts, milk, seafood, egg and tree nuts) insect stings and some medications.

Within minutes of exposure to the allergen, the allergic person can have potentially life threatening symptoms which can include:

  • Swelling and tightness in the throat
  • Becoming pale and floppy in young children
  • Swelling of the tongue
  • Difficulty in breathing
  • Wheezing and coughing
  • Dizziness or collapse

Causes of Food Allergy

90% of food allergic reactions are caused by:

  • Peanuts (peanuts are actually legumes not true nuts)
  • Tree nuts
  • Fish
  • Shellfish
  • Soy
  • Wheat
  • Milk
  • Eggs

Treatment and Management

The best and easiest way to treat food allergies or food intolerances is to completely eliminate the offending foods.  In fact with a true food allergy it is absolutely crucial that there is no contact with the offending food.

A mother who has eaten a peanut butter sandwich who then kisses her child who has a peanut allergy, puts the child at risk of an anaphylactic reaction. The best course is that the foods that someone is allergic to are not kept in the house at all and all family members should adhere to the same eating needs as the allergic member of the family.

The management of food intolerances may involve an elimination diet. Once a diagnosis is made (migraines, hives, bowel issues etc), a history is taken by Dr Katzen to help identify the role of diet in your symptoms.

This may then involve a diet of elimination which removes the suspected food culprits. This is done under our supervision. If removing the food helps your symptoms, this can be followed by challenges under controlled conditions to identify dietary triggers which may need to be avoided in the future.