Elimination diets are diets in which people stop
eating specific foods for a period and then challenge
their body by adding the food back into their diet and
evaluating how the body responds. Elimination diets
are used to detect food allergies and food intolerances.
They are not nutritionally balanced and are intended
to be used only for diagnostic purposes.
Adverse reactions to food fall into two main categories,
food allergies, and food intolerances. Food
allergies cause a response by the immune system.
When a person has a food allergy, his or her body
responds to something in food by treating it like a
threatening foreign material. Immune system cells
produce proteins called antibodies that act to disable
this material. This process often causes inflammation
and results undesirable symptoms that range from
mild and annoying to life threatening. The reason
why some people respond to certain foods and others
do not is probably genetically based.
Food intolerances, on the other hand, also cause
adverse reactions, but these reactions do not involve
the immune system and are not life threatening. Lactose
(milk sugar) intolerance is an example of a food
intolerance. It is caused by the body producing too
little of the enzyme needed to digest lactose. Interestingly,
although surveys show that in the United States
up to 30% of families believe they have at least one member with a food allergy, the actual documented
rate of food allergies is about 6% in infants and children
and 3.7% in adults. On the other hand, in Hispanic,
Jewish, and Southern European populations,
the rate of lactose intolerance is about 70%, and it
reaches 90% or more in Asian and African populations.
Food intolerances are much more common, but
true food allergies tend to be much more severe. In this
article, food sensitivities are 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, wheezing,
and hay fever-like symptoms. These symptoms
may occur immediately after eating the trigger food
or may not develop for hours. Most immediate reactions
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 anaphylactic
shock who were brought for treatment to the
emergency room at the at the Mayo Clinic in Minnesota,
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, and soy, however, sensitivities
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 modified
by the physician):
-grains: rice and rice products, sago, tapioca, buckwheat
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, sunflower
oil, safflower oil, salt, garlic
-beverages: water, fresh pear juice
The individual must avoid all medicines containing
aspirin (salicylates) and food colorings. After several
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.
