Food Allergies
Allergy or Something Else?
The following in-depth article on food allergy testing is
by Kelly Dorfman M.S., L.N. and cofounder of the Developmental
Delay Registry. It originally appeared in the Registry's fall 1999
newsletter.
Allergy or Chemical Reaction?
Intolerance to certain foods, especially
gluten (wheat related grains) and casein (milk protein), is a common
occurrence among children with developmental delays. Before adopting an
elimination diet, however, many parents consult an allergist to determine
if the diet is necessary. Surprisingly, after extensive scratch testing,
the child is often found not to be allergic to any foods. Some parents
choose to eliminate gluten and casein proteins anyway, and find their
youngster responds with improved attention, sleep and/or language skills.
How is this improvement possible if the child was not allergic in the
first place? The answer lies in understanding the difference between allergies
and other types of chemical reactions within the body.
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IgE versus IgG Reactions
Allergies are defined as specific reactions within the immune
system involving an antibody called immunoglobulin
E (IgE). Immediate responses such as hives, congestion or swelling
typically result from IgE activity. Traditional scratch testing identifies
IgE triggers such as pollen or peanuts, which can cause symptoms that
range from annoying to lethal.
Very different responses are delayed allergy reactions.
If they occur more than two hours after eating a food, they may result
from immunoglobulin G (IgG) rather than IgE activity.
IgG reactions may cause symptoms such as sleep disturbances, subsequent
bed wetting, sinus and ear infections, or crankiness. Blood tests rather
than scratch tests are the only way to screen for IgG allergies.
Where immunoglobulins are involved, the word “allergy” can
legitimately be used to describe symptoms after exposure. A reaction to
gluten or casein sometimes shows up in IgG or IgA blood testing, and is,
therefore, referred to as an “allergy.”
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Poor Digestive Functions
Poor digestive function has a number of causes. It may result
from an immature gut in infants and from heavy antibiotic usage or the
lack of the protein digesting enzyme DPP4. The possible relationship between
the lack of DPP4 enzyme and the symptoms of PDD/autism is the recent discovery
of Dr. Alan Friedman at Johnson & Johnson Labs. Without essential digestive
enzymes, such as DPP4, partially digested proteins such as gluten and
casein may leak into the blood.
Partially digested proteins have odd configurations and
mimic other complex molecules such as endorphins. Endorphins are nervous
system proteins that act as painkillers. Partially digested gluten or
casein proteins may bind to pain killing (opiate) receptors and cause
behavioral symptoms of poor eye contact, irritability, or disconnection.
Poor digestion may or may not elicit an immunoglobulin response.
It may cause inflammation symptoms instead, such as intestinal irritability,
stomachache and/or diarrhea. These reactions are not technically allergies.
Nor is opiate activation technically a true allergy. When IgG
or IgE testing finds milk or gluten sensitivity,
it is because the chemical messages weaving through the body tripped the
allergy system.
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Other Gut Problems
Similarly, when reactions to a food are aggression, poor
concentration, or seizures, many other explanations are possible. All
body systems are interdependent and so intertwined that designing tests
to understand and study their discrete functions can be very difficult.
The artificial distinctions placed between immune and neurological systems
hinder diagnosis and treatment. This imprecise diagnosis can be very frustrating,
but there are too many ways for the body to react and communicate. That
is, it is unlikely that one testing system will ever be able to find and
sort all possible reactions.
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Best "Test" for Reactions
The best “test” for reactions is elimination of suspect
items. The limitation with this approach is that irritants can interact.
That is, exposure to one item will not cause symptoms, but when two mildly
reacting foods are present, together they trip a response by overloading
the system. In “load” reactions, a little is tolerable, but too much of
one or a combination of two or more causes trouble. Blood testing may
then be useful, but the problem in load allergies is usually a leaking
gut.
Rather than eliminating additional foods, the answer is
repairing the underlying leak. The reason that secretin has been extremely
useful in autism is its ability to correct gut function (see New Developments,
4:2). For more information about IgE and IgG reactions and the leaky gut,
read Biological Treatments for Autism and
PDD and The Leaky Gut Syndrome.
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