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
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
Type l - occurs within 60 minutes of exposure. Reactions
- Abdominal cramps
- 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,
- Poor appetite, feeding difficulties
- Behaviour and mood changes, rocking, hyperactivity, poor
- 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
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
By the age of 8 to 9 months start to introduce:
- Green vegetables
- Unprocessed meat and chicken
From 9 to 12 months
- Dairy e.g. plain yoghurt, cottage cheese, goats milk products
- Beans, lentils, chickpeas
- Citrus and other fruits
From 18 to 24 months
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
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
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
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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