FOOD ALLERGY
The following food
allergy information is from
Alberta Children's Services:
Website:
http://www.child.gov.ab.ca
An allergy is the body’s extreme reaction to a
substance that is usually harmless. A food allergy can be mild, serious or
can even cause death. Some people react to a food within minutes, while
other reactions may take hours. In general, the more serious the allergy
the faster the body reacts. The substance that causes an allergic reaction
is called an allergen. When a person has an allergic reaction to food:
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The immune system attacks
the substance in the food ( allergen ) as if it were a bad germ. The
fighters in the immune system are called antibodies.
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The antibodies make the
body release chemicals to clear the allergen from the body.
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These chemicals can cause
swelling and irritation or other problems in certain parts of the body.
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The most common symptoms of an allergic
reaction to food include:
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Throat, nose and lungs:
stuffy or runny nose, asthma, throat swelling.
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Skin: itchy skin or eyes,
rashes, hives, eczema and swelling, especially around the mouth and
face.
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Stomach: diarrhea,
constipation, nausea, vomiting, bloating, stomach pain.
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Other: anaphylaxis
(sudden, severe reaction that involves many body systems), failure to
thrive, headaches, paleness, dark circles under the eyes.
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Unlike a food allergy, a food intolerance does
not involve the immune system. Food intolerance is a general term that
describes many types of reactions to food or food additives. For example,
you might get an upset stomach from the lactose in milk or the fibre in
cereals. The symptoms of a food intolerance can be mild or serious.
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It can be hard to determine if the problem is
a food allergy. In some cases, you can simply take the food out of your
diet to see if the symptoms go away. In other cases, you may have a hard
time finding the cause because many things can cause the same problems. To
find out if a problem is a food allergy, follow these steps:
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Visit a doctor to rule
out other problems that would cause the same symptoms.
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Keep a diary of all food,
drinks, medications or supplements you take and note any reactions.
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Your doctor can decide if
you should see an allergist. An allergist might do the
following:
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Skin tests. The
allergist scratches a small amount of the allergen under the skin. If
an itchy bump appears, there has been a reaction. The skin test does
not always give a clear response, so it is not always helpful for
diagnosing food allergies.
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Challenge diets. The
suspected food is eliminated from the diet until the symptoms go away
(about five to 10 days). The foods are slowly added back to see if
your body reacts. This diet should be planned with the help of a
registered dietitian. You do not usually follow a challenge diet for
longer than two weeks.
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Any kind of food can be an allergen. The most
common problem foods are cow’s milk, eggs, nuts, peanuts, fish and
shellfish. Other common food allergens are wheat, tomatoes, strawberries,
oranges and soybeans.
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People react differently to food allergens.
When reactions are mild, you can occasionally eat a small amount of the
problem food. When reactions are more serious, even smelling the food
might cause a reaction. Cooking a food can sometimes help but fish, nuts
and peanuts should be avoided in any form if you know they cause an
allergic reaction.
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Avoid the food that
causes the problem. If you must avoid many foods, a registered
dietitian or a community health nutritionist can help you plan a
balanced diet.
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Learn to read labels.
Other forms of the food are sometimes in packaged foods. For example,
casein is a milk protein that may cause problems for people with a milk
allergy.
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Check the ingredients of
any medications or supplements before you take them. Ask a pharmacist
for help.
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Food allergies probably cannot be prevented
but certainly can be delayed. If you do not have a family history of food
allergies, eat a balanced diet by choosing healthy foods from Canada’s
Food Guide to Healthy Eating. However, if you have a family history of
food allergies, there are some steps you can take to lower the risk for
your children:
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If you are pregnant,
during the last three months of pregnancy avoid the foods you are
allergic to, and reduce the amounts of foods eaten that are most likely
to cause allergic reactions.
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Breastfeed for at least
the first six months (some sources recommend up to twelve months). Food
allergens can be passed to the baby though breast milk. If you have a
strong family history of allergies, a more restricted diet may be
necessary. You should discuss this with your physician. A registered
dietitian can help you plan a balanced diet and can recommend vitamin
and mineral supplements if you need them.
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Do not give solid foods
until the baby is six months old. Avoid those foods that are most likely
to cause allergic reactions until the baby is at least one year old.
Avoid eggs until age two. Avoid peanuts, nuts, fish and shellfish until
age three.
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When you introduce solid
foods to a baby with a family history of food allergies, try one new
food every two to three weeks and watch for any reaction.
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Reproduced with permission from the Capital Health Authority
Last reviewed May 2003
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