member with a food allergy, the actual documented
rate of food allergies is about 6% in infants and chil-
dren and 3.7% in adults. On the other hand, in His-
panic, Jewish, and Southern European populations,
the rate of lactose intolerance is about 70%, and it
reaches 90% or more in Asian and African popula-
tions. Food intolerances are much more common, but
true food allergies tend to be much more severe. In this
article,food sensitivitiesare used to include both food
allergies and food intolerance.
The most common symptoms of food sensitivities
are nausea, diarrhea, bloating, excessive gas, hives,
rashes, eczema, headaches, migraine, asthma, wheez-
ing, and hay fever-like symptoms. These symptoms
may occur immediately after eating the trigger food
or may not develop for hours. Most immediate reac-
tions are severe allergic responses that can result in
anaphylactic shock, a condition in which the airways
swell shut and the person cannot breathe. One study
found that in about one-third of individuals in ana-
phylactic shock who were brought for treatment to the
emergency room at the at the Mayo Clinic in Minne-
sota, the shock trigger had been a food. Foods most
likely to cause immediate reactions are peanuts, tree
nuts, and shellfish.
Delayed symptoms are difficult to detect and are
sometimes called ‘‘maskedrdquo; food sensitivities.
The most common causes of delayed sensitivities are
dairy products, egg, wheat, andsoy, however, sensi-
tivities vary widely and can be caused by many foods.
The amount of a trigger food that it takes to cause a
response varies considerably from person to person.
A true elimination diet is very rigorous and needs
to be implemented under the direction of a physician
often in consultation with a dietitian or nutritionist.
For the elimination diet to be useful, the patient must
follow the diet strictly. Cheating invalidates the results.
For 2–3 weeks, a person on the elimination diet
eats only the following foods (This list may be modi-
fied by the physician):
grains: rice and rice products, sago, tapioca, buck-
wheat products, millet products
proteins: veal, lamb, chicken, turkey, rabbit, tuna,
bream, whiting, dried peas, lentils
fruit: peeled pears, peeled apples, pawpaw.
vegetables: potatoes, sweet potatoes, lettuce, parsley,
bamboo shoots, celery, cabbage
sweeteners and seasonings: sugar, maple syrup, sun-
flower oil, safflower oil, salt, garlic
beverages: water, fresh pear juice
The individual must avoid all medicines contain-
ing aspirin (salicylates) and food colorings. After sev-
eral weeks on these restricted foods, one new food is
introduced in larger than normal amounts. This is the
challenge food, and it is eaten for three days in a row.
If no symptoms appear, the dieter continues to eat that
food in normal amounts and adds another challenge
food. If symptoms appear, the challenge food is
stopped immediately and no new challenge food is
introduced until symptoms disappear. During this
time the dieter keeps a food journal, writing down
everything that is eaten and any symptoms, either
physical or emotional, that appear. It can take 2 to 3
months to work through all challenge foods.Function
Elimination diets are the first part of a diagnostic
technique for determining what foods are causing
undesirable symptoms. Their purpose is to prepare
the patient for the second part of the diagnostic proc-
ess, the food challenge by cleansing the body of all
possible foods that could be causing the symptoms.
During the challenge phase, the patient eats the sus-
pect food and waits to see if symptoms reappear.
Elimination and challenge give healthcare professio-
nals a way to reproducibly pinpoint exactly which
foods are causing an adverse reactions so that the
patient can exclude these foods from their diet.Benefits
People with symptoms that interfere with their
daily life benefit greatly from pinpointing which
foods are causing the symptoms so that these foods
can be eliminated from the diet. People with less severe
symptoms may find the process of elimination and
challenge too costly and disruptive to make it
worthwhile.Precautions
Many people who suspect that certain foods are
causing their symptoms try modified elimination dietsKEY TERMS
Antibody—A protein produced by the immune sys-
tem to fight infection or rid the body of foreign
material. The foreign material that stimulates the
production of antibodies is called an antigen. Spe-
cific antibodies are produced in response to each
different antigen and can only inactivate that par-
ticular antigen.Elimination diets