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CHILDHOOD FOOD ALLERGIES - a parent's guide
Vicki Martin - Dietitian
What is a food allergy?
Food allergy is the result of an immune reaction by the
body to normally harmless substances in foods. These substances
are called antigens or allergens. For a variety of reasons
some children's immune systems release antibodies and histamines
in response to these allergens.
Reactions may occur within minutes of eating the allergen
(Type 1 hypersensitivity), or be delayed up to 48 hours
after consuming the food (Type 4 hypersensitivity).
The release of histamines in the body may cause a variety
of symptoms:
Type l - occurs within 60 minutes of exposure. Reactions
include:
Abdominal cramps
Colic
Vomiting
Diarrhoea
Difficulty in breathing
Low blood pressure, fainting
Itching (rashes, welts, swelling, hives)
Type 4 - occurs within hours or days of exposure and may
be dependent on the amount of allergen consumed. Reactions
include:
Eczema, dermatitis
Asthma, hay fever, sinusitis, persistent cough, runny nose,
ear infections
Constipation
Sweating
Poor appetite, feeding difficulties
Behaviour and mood changes, rocking, hyperactivity, poor
attention
Sleep problems
Why do allergies occur?
Typically a reaction occurs because a foreign protein (antigen
or allergen) is absorbed from the digestive system into
the blood. The production of antibodies and histamines are
the body's protective mechanism against these.
Children may inherit tendencies towards allergies. The
stronger the family history of allergies e.g. asthma, eczema,
hay fever - the earlier the child is likely to develop these.
Sensitivity may also develop when the digestive system
of the child is immature and comes into contact with new
foods and substances.
Allergy prevention
Where there is a known family history the mother should
avoid suspected foods throughout her pregnancy and breastfeeding.
To avoid the possibility of nutrient deficiencies she should
consult a registered dietitian for dietary guidance.
Breastfeeding exclusively up to the age of six months
helps to reduce the possibility of allergies developing
for any child. For infants requiring bottle feeding before
the age of six months, look for hypoallergenic (low allergy)
formulas.
Care must be taken with all infants at the introduction
of solids. Because the digestive system is very immature
it may allow the absorption of foreign proteins which would
normally not be allowed to pass into the blood system.
Do not be in a hurry to start feeding different foods.
Introduce one new food per week. All foods should be cooked.
The least allergenic foods to start with are rice, pears,
yellow and root vegetables.
By the age of 8 to 9 months start to introduce:
Oats
Green vegetables
Unprocessed meat and chicken
From 9 to 12 months:
Wheat
Soy
Dairy e.g. plain yoghurt, cottage cheese, goats milk products
Beans, lentils, chickpeas
Tomatoes
Citrus and other fruits
From 18 to 24 months:
Eggs
Berry fruits
From age 3:
Peanuts, nuts
Fish and shellfish
Avoid processed meats e.g. ham and bacon, also chocolate,
spices, colourings, artificial flavourings, fruit drinks
and juices. Be cautious with cow's milk and cheese, pork,
beef, citrus fruits, and all gluten containing grains (e.g.
wheat and rye; rice and millet are gluten free).
Suspect a food allergy? Here's what to do:
Your health practitioner can arrange for various skin and
other food sensitivity tests. These are not considered to
be completely reliable however and may return false negative
and false positive results in some cases. Do not depend
on them completely to alter your child's diet.
Careful elimination of the suspected foods give the best
results and allow for less reduction of important nutrient
containing foods. The advice of a registered dietitian is
important to prevent any nutrient deficiencies developing.
Suspected foods should be removed from the diet for four
to six weeks then reintroduced while carefully noting any
recurrence of symptoms. Introduce suspected foods one week
apart to allow for delayed reactions.
Further information:
For advice and support contact your local Allergy Awareness
Association. Registered dietitians can provide dietary guidelines,
food substitute guidance, packaged and takeaway food "free
from" lists, and food additive lists.
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