To find out the
difference between food allergy and food intolerance, your
provider will go through a list of possible causes for your
symptoms. This is called a “differential diagnosis.”
Food Allergy or Food Intolerance?
If you go to your healthcare provider and say, “I think I
have a food allergy,” your provider has to consider other
possibilities that may cause symptoms and could be confused
with food allergy, such as food intolerance. To find out the
difference between food allergy and food intolerance, your
provider will go through a list of possible causes for your
symptoms. This is called a “differential diagnosis.” This type
of diagnosis helps confirm that you do indeed have a food
allergy rather than a food intolerance or other illness.
Types of Food Intolerance
Food poisoning
One possible cause of symptoms like those of food allergy
is food contaminated with microbes, such as bacteria, and
bacterial products, such as toxins. Contaminated meat and
dairy products sometimes cause symptoms, including GI
discomfort, that resemble a food allergy when it is really a
type of food poisoning.
Histamine toxicity
There are substances, such as the powerful chemical histamine,
present in certain foods that cause a reaction similar to an
allergic reaction. For example, histamine can reach high levels
in cheese, some wines, and certain kinds of fish such as tuna
and mackerel.
In fish, histamine is believed to come from contamination by
bacteria, particularly in fish that are not refrigerated properly.
If you eat one of these foods with a high level of histamine, you could have a reaction that strongly resembles an allergic
reaction to food. This reaction is called “histamine toxicity.”
Lactose intolerance
Another cause of food intolerance confused with a food allergy
is lactose intolerance or lactase deficiency. This common food
intolerance affects at least 1 out of 10 people.
Lactase is an enzyme that is in the lining of your gut. Lactase
breaks down or digests lactose, a sugar found in milk and most
milk products.
Lactose intolerance, or lactase deficiency, happens when there
is not enough lactase in your gut to digest lactose. In that
case, bacteria in your gut use lactose to form gas which causes
bloating, abdominal pain, and sometimes diarrhea.
Your healthcare provider can use laboratory tests to find out
whether your body can digest lactose.
Food additives
Another type of food intolerance is a reaction to certain
products that are added to food to enhance taste, provide
color, or protect against the growth of microbes. Several
chemical compounds, such as MSG (monosodium glutamate)
and sulfites, are tied to reactions that can be confused with
food allergy.
MSG
MSG is a flavor enhancer and, when taken in large
amounts, can cause some of the following signs:
• Flushing
• Sensations of warmth
• Headache
• Chest discomfort
• Feelings of detachment
These passing reactions occur rapidly after eating large amounts of food to which MSG has been added.
Sulfites
Sulfites occur naturally in foods or may be added to increase crispness or prevent mold growth.
Sulfites in high concentrations sometimes pose
problems for people with severe asthma. Sulfites
can give off a gas called sulfur dioxide that a
person with asthma inhales while eating food
containing sulfites. This gas irritates the
lungs and can send an asthmatic into
severe bronchospasm, a tightening of
the lungs.
The Food and Drug Administration
(FDA) has banned sulfites as spray-on
preservatives in fresh fruits and vegetables.
Sulfites are still used in some foods,
however, and occur naturally during
the fermentation of wine.
Gluten intolerance
Gluten intolerance is associated with the disease called
“gluten-sensitive enteropathy” or “celiac disease.” It happens
if your immune system responds abnormally to gluten, which
is a part of wheat and some other grains. Some researchers
include celiac disease as a food allergy. This abnormal immune
system response, however, does not involve IgE antibody.
Psychological causes
Some people may have a food intolerance that has a psycho
logical trigger. If your food intolerance is caused by this type
of trigger, a careful psychiatric evaluation may identify an
unpleasant event in your life, often during childhood, tied to
eating a particular food. Eating that food years later, even as
an adult, is associated with a rush of unpleasant sensations.
Other causes
There are several other conditions, including ulcers and
cancers of the GI tract, that cause some of the same symptoms
as food allergy. These symptoms include vomiting, diarrhea,
and cramping abdominal pain made worse by eating. Diagnosis
|
