What is a food allergy?
A food allergy is an immune
system response. It is caused when the body mistakes an ingredient
in food-usually a protein-as harmful and creates a
defense system (antibodies) to fight it. An allergic reaction
occurs when the antibodies are battling an "invading" food protein.
The most common food allergies in adults are shellfish, peanuts,
fish and eggs. The most common food allergies in children are milk,
soy products, peanuts and shellfish.
What is food intolerance?
Food intolerance is a
digestive system response rather than an immune system response. It
occurs when something in food irritates a person's digestive
system or when a person is unable to properly digest, or breakdown,
the food. Intolerance to lactose, which is found in milk and other
dairy products, is the most common food intolerance.
What are the symptoms of a food allergy?
Symptoms
of a food allergy can range from mild to severe, and the amount of
food necessary to trigger a reaction varies from person to person.
Symptoms of a food allergy may include:
- Rash or hives
- Nausea
- Cramping stomach pain
- Diarrhea
- Itchy skin
- Shortness of breath
- Chest pain
- Swelling of the airways to the lungs
Anaphylaxis is a very serious and potentially fatal allergic
reaction that involves a sudden drop in blood pressure, loss of
consciousness and body system failure.
What are the symptoms of food intolerance?
Symptoms
of food intolerance include:
- Nausea
- Stomach pain
- Gas, cramps or bloating
- Vomiting
- Heartburn
- Diarrhea
- Headaches
- Irritability or nervousness
How common are food allergies and intolerances?
Food allergies affect about 1 percent of adults and 7 percent of
children, although some children outgrow their allergies. Food
intolerances are much more common. In fact, nearly everyone at one
time has had an unpleasant reaction to something they ate. Some
people have specific food intolerances. Lactose intolerance, the
most common specific food intolerance, affects about 10 percent of
Americans.
What causes food allergies and intolerances?
Food
allergies arise from sensitivity to chemical compounds (proteins)
in food, even compounds that are found naturally in food. Food
allergies are more common in people whose family members have
allergies, suggesting a genetic-or hereditary-factor
may be involved with the development of food allergies.
Food allergies develop after you are exposed to a food protein
that your body thinks is harmful. The first time you eat the food
containing the protein, your immune system responds by creating
specific disease-fighting antibodies (called immunoglobulin E or
IgE). When you eat the food again, it triggers the release of IgE
antibodies and other chemicals, including histamine, in an effort
to expel the protein "invader" from your body. Histamine is a
powerful chemical that can affect the respiratory system,
gastrointestinal tract, skin or cardiovascular system.