It is important to make a distinction between food allergy and food intolerance. Food allergies act in the same way as other allergies: a first phase of sensitization, followed by a second phase of allergic reaction caused by contact with the allergen.
Intolerance is an adverse reaction or hypersensitivity to some ingested substances. In allergies, immunoglobulins play a key role, while T lymphocytes are involved in intolerance.
Depending on the type of intolerance, it is possible that a small amount of non-tolerated food can be eaten by a person without triggering a reaction. Conversely, if the problem is food allergy, even a small amount of food can trigger an allergic reaction. Food allergies can cause severe symptoms and even anaphylactic shock. The most frequent allergens are some types of proteins contained in:
- Crustaceans
- Peanuts
- Nuts
- Milk
- Egg
- Fish
Many patients suffering from allergic rhinitis can be severely affected by fresh fruits and vegetables, as well as some types of nuts and spices. An allergic reaction can include typical symptoms such as itching and tingling in the mouth. In some patients, such an allergy syndrome, also called oral allergy syndrome (OAS), can cause swelling of the throat and anaphylactic shock. OAS is an example of cross-reactivity. The proteins found in fruits and vegetables can cause a reaction because they are very similar to those found in some pollen. Cooking fruits and vegetables before eating them can help avoid allergic reactions. Cooked fruits and vegetables usually do not cause any cross-reactivity. Below are some examples of frequent allergy cross-reactivity between pollen and fruits/vegetables. If you are allergic to birch pollen you may also be allergic to:
- Apple
- Carrot
- Celery
- Hazelnut
- Fishing
- Pear
- Raw potato
If you are allergic to ragweed pollen you may also be allergic to:
- Bananas
- Melons
- Watermelon
- Tomatoes
If you are allergic to mugwort pollen you may also be allergic to:
- Apples
- Carrots
- Celery
- Kiwi
- Peanuts
- Spices (cumin, parsley, coriander, anise, fennel).
Prevent allergies
The only way to definitely avoid any allergic reactions is to avoid foods that contain allergens. However, despite all precautions, it is possible to accidentally come into contact with allergens.
In everyday life, it is very important to minimize the risk of involuntary intake of offending food. Don't take anything for granted! Read labels carefully to make sure a particular food does not contain traces of what you are allergic to.
When in doubt, refuse! It is not always easy to identify all the ingredients, e.g. when it comes to a dinner out, then better not to risk it. Not everyone understands how serious an allergic reaction is. If the allergic person is a child, all relatives, teachers and babysitters must be involved.
