Food Allergies

A food allergy is an abnormal response of the body's immune system to specific food proteins or food additives. An allergic reaction to food can range from mild to serious.

Symptoms of an allergic reaction may begin to develop within minutes or within about an hour after eating the food. In general, the more serious the allergy, the faster the body reacts.

The most common symptoms of an allergic reaction to food include:

• itchy lips or tongue
• swelling of the throat
• hives
• trouble breathing
• eczema
• swelling

The most serious reactions can lead to shock, which involves multiple systems of the body. Shock may lead to trouble breathing, coma, and even death if not treated.

What is a food intolerance?

Unlike a food allergy, a food intolerance does not involve the immune system. Food intolerance is a term that describes many types of reactions to food or food additives. For example, the lactose in milk products may cause an upset stomach or diarrhea.

The symptoms of food intolerance can range from mild to serious. Depending on the food, there may be different symptoms like gas, abdominal cramps and diarrhea, or symptoms like chronic headaches.

What are the most common food allergies?

Any kind of protein found in food can be an allergen. The most common problem foods are milk, eggs, tree nuts, peanuts, wheat, soy, fish, and shellfish.

Is it a food allergy?

To find out if a health problem is a food allergy, follow these steps:

1. Make an appointment to see your doctor. Your doctor will decide if you should see an allergist (a doctor who specializes in allergies).
2. Keep a diary of all food, drinks, medications, or supplements taken and note any reactions or troublesome symptoms.

If your diet requires changes, ask for a referral to a Registered Dietitian.

If a true food allergy has been diagnosed:

• Avoid the food that causes the problem. If you have multiple food allergies, a Registered Dietitian can help you plan a healthy, balanced diet.
• Learn to read food labels and know what to look for on the label. For example, please allergic to milk may have problems with the ingredient casein, which is a milk protein.
• Check the ingredients of any medications or supplements before you take them. Ask a pharmacist for help.
• Find out from your doctor the type of medication you may need to carry with you or take if you have an allergic reaction.

Can food allergies be prevented?

There is some evidence that food allergies may be delayed or even prevented with changes to the diet. There are some steps you can take to lower your child's risk of food allergies.

• If you are pregnant, eat a healthy, balanced diet with a variety of foods from Canada's Food Guide to Healthy Eating. Avoid all foods that you are allergic to. Talk to a Registered Dietitian about healthy food substitutes or supplements if you must restrict your diet because of food allergies.
• Currently, there is no scientific proof that avoiding highly allergenic foods (like nuts) during pregnancy will prevent allergies in infants. If you choose to restrict or reduce allergenic foods from your diet while you are pregnant or breastfeeding, talk to a Registered Dietitian for help in planning a healthy diet.
• If there is a family history of allergies, your infant may be at higher risk for developing allergies. You may be able to prevent or delay the onset of allergies by exclusive breastfeeding and delaying the introduction of solids until your infant is at least 6 months old.
• Some infant food allergies to milk, eggs, soy, or wheat may resolve by school age. Other allergies are life-long. Talk to your doctor about your infant's specific food allergies.

Review Date :

October 2007

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