Skip to main content

Allergies

Who is likely to develop a food allergy?

Infants and toddlers are most likely to develop a food allergy because food allergies occur early in life when the immune and digestive systems are not fully matured.

Is it true that "once allergic, always allergic" when it comes to food allergies?

Not at all. Health Canada reports that about 8% of children under one year of age have one or more food allergies. Food allergies tend to disappear with age, i.e. children often outgrow them by five years of age. This is reflected in the Health Canada statistic which states that only 1-2% of Canadians have food allergies. Allergies to certain foods (e.g. eggs, milk and soy) are more likely to be outgrown than allergies to other foods (e.g. peanuts, tree nuts, wheat, fish and seafood). For this reason, in conjunction with your doctor, periodic rechallenging with an "offending food" is often done, except in cases where a very serious reaction has occurred.

If I have a food allergy, will my baby?

This is a common question of pregnant women and new parents. Before one can answer the question, it needs to be known if it is a true food allergy or merely a food intolerance. A true food allergy affects the immure system and is rare; a food intolerance does not affect the immune system and is more common. A proper diagnosis can only be made after appropriate testing by a qualified allergist. Although anyone can develop a food allergy, food allergies are mostly inherited. A child with one allergic parent is twice as likely to develop a food allergy, while a child with two allergic parents is four times as likely to develop a food allergy, compared to a child with no allergic parents.

If there is a family risk of developing food allergies, what can I do to help prevent my baby from having food allergies?

New parents should follow a feeding approach which is "gradual" and "conservative" when introducing foods. More specifically, this means delaying the introduction of major food allergens. This approach may prevent, decrease the severity of, or delay the onset of food allergies by allowing the infant's immune system to fully develop before it is exposed to potentially allergic foods. Major food allergens for infants are: milk, egg, peanuts, soy, tree nuts (e.g. almonds, pecans, walnuts) and wheat. Together, these foods cause about 95% of all food allergy reactions. For example, when it comes to eggs... current guidelines for the feeding of healthy infants i.e. where there is no family history of food allergies, recommend introducing cooked egg yolk at nine months and cooked egg white at about 12 months. However, in the case where there is a family history of food allergies, it is advised that eggs not be introduced until after one year of age, usually between one and two years of age. It is strongly advised to consult with your doctor or allergist to determine what time is best. When introducing egg yolk, it is often easiest to hard cook the egg and then "peel off"' the white.

What are the symptoms of food allergy?

Symptoms for food allergies are many, varied and very individualistic. Often they can be vague enough so that it is unclear whether it is a true food allergy or some other illness or problem. A few examples of common symptoms include: hives, itching, swelling of any body part, red and watery eyes, runny nose, vomiting, diarrhea, coughing and wheezing. In a small number of cases, anaphylaxis can result.

When do symptoms occur?

To determine if a child has a food allergy rather than another ailment, it is important to know that symptoms of a food allergy happen suddenly (within minutes to hours after a child has eaten) and go away within 24 hours. Always let a doctor know if any symptoms occur with the introduction of a new food.

Can a person allergic to eggs eat chicken?

In most cases, the answer is yes. Most often the antibodies against eggs identify chicken as non-egg and chicken can be eaten safely. In rare cases, the antibodies find a similarity between the protein structure of chicken and eggs and the child can react to both.

Can a person allergic only to egg white still eat the yolk?

Eggs have two allergenic components with different properties - the yolk and the white. The egg white is the component which causes the most severe reactions. However, it makes little difference which part of the egg a child is allergic to. It is very difficult to separate the white from the yolk without having some parts of each combine. Extremely small amounts can sometimes trigger severe reactions.

Can a person who is allergic to raw eggs eat cooked eggs?

Usually not. Egg white is only slightly modified by heat, making it allergenic either raw or cooked. Egg yolk is substantially altered by heat and it can be tolerated by some if it is well cooked. But remember, it is very difficult to separate the white from the yolk without having some parts of each combine. However, sometimes when the allergy is disappearing, a person can eat cooked eggs but still react to raw eggs.

Is baking possible if a person is allergic to eggs?

Though eggs are an important ingredient in baking, there are substitutions which can be used. For best results though, use recipes with only 1 or 2 eggs. Egg-free baking gets easier with practice.

For each egg called for in a recipe, substitute ONE of the following:

  • 5 mL (1 tsp) baking powder, 25 mL (1½ tbsp) water and 25 mL (1½ tbsp) oil
  • 5 mL (1 tsp) baking powder, 15 mL (1 tbsp) water and 15 mL (1 tbsp) vinegar
  • 5 mL (1 tsp) yeast dissolved in 50 mL (¼ cup) warm water
  • 1 packet of unflavoured gelatin, 30 mL (2 tbsp) of warm water. Do not combine until ready to use.
  • ½ large mashed banana
Commercial egg substitutes are also available.

Where can I get more information on allergies?

Talk to your family doctor, allergist or a nutritionist or nurse at your public health unit.


References:

1. Nutrition for Healthy Term Infants: Statement of the Joint Working Group - Canadian Paediatric Society, Dietitians of Canada and Health Canada, 1998.

2. Managing Food Allergy and Intolerance - A Practical Guide, J. Vickerstaff Joneja, 1995.

3. Understanding Food Allergies: A Guide to Food and Egg Allergies, Egg Nutrition Centre.