What is a food allergy?
response to a food that the body mistakenly believes is harmful. Although
an individual could be allergic to most any food, there are eight foods that account for 90% of all food-allergic
These are: milk, egg, peanut, tree nut (walnut, cashews, almonds, and so forth), fish, shellfish,
soy and wheat.
Once the immune system decides that a particular food is harmful, it creates
. This involvement of the immune system is what sets a true food allergy apart from other adverse food
reactions. The antibodies produced by the immune system begin a chain of reactions leading to the manifestation
of allergic symptoms that can affect the respiratory system, gastrointestinal tract, skin, or cardiovascular system.
Scientists estimate that approximately 12 million Americans suffer from true food allergies.
A true food allergy
immediate, consistent, immune-mediated reaction to a food that is largely dose-dependent and
usually begins in childhood
. Another hallmark of a food allergy is that the reaction is not seen until the second
(or later) exposure to the food product, giving the body the chance to produce the necessary antibodies.
Adverse reactions to food- An
to a food is any unexpected reaction to a food whether mediated
by the immune system or not. The perceived
6-8% in children,
1-2% in adults.
with confuse food intolerance with food allergies.
are adverse reactions to food that do not
involve the immune system.
is one example of a food intolerance.
The immune response to an allergen
(take notes on the animation too)
A food allergy occurs when the immune system reacts to a
immunoglobulin E (IgE)
to a protein. These IgE antibodies cover the surfaces of
which line the
and are found in the
When eaten or inhaled, the allergen will react with the IgE
antibodies on the mast cells, releasing histamine and causing swelling and itching of the skin and throat,
sometimes diarrhea and vomiting and, if left untreated, may cause anaphylaxis and death.
An 11 year old girl suffers from recurrent headaches and behavioral problems. Her mother has noted that
her symptoms worsen whenever she eats chocolate, strawberries, cocoa-cocoa puffs, or drinks soda.
A mother says her 5-year old son ‘goes crazy’ when he eats popsicles or drinks any beverage with