Food allergies: Symptoms, causes, testing and treatment

Who's most at risk?
In Canada, deaths from severe food allergies are rare, thanks to epinephrine auto injectors and increased awareness. But deaths do happen, especially among teens and young adults. "This group takes the highest risks," says Vadas. These people might think they can get over a food allergy, or they're in denial and keep eating the food that makes them sick. "The people who die typically don't have a rescue medication [epinephrine] with them."

Children are at lower risk of death because of attentive parents and growing awareness in schools. Older adults have a lower risk because they are more careful, and because food allergies are most prevalent in children, and less so in adults.

The bottom line for food allergy sufferers is be alert about what you eat at all times, and carry an epinephrine auto injector.

The scoop on food intolerances
Food allergies and food intolerances are not the same. A food allergy results from part of the immune system reacting to a specific protein in the food you're allergic to. Food intolerances (sensitivities) result from a large number of medical conditions, most of which have nothing to do with the immune system. Dr. Peter Vadas, an allergist, immunologist and associate professor of medicine at the University of Toronto, explains the types of food intolerances.

A low level of a digestive enzyme causes one type of intolerance. For instance, people with low levels of the enzyme lactase cannot properly metabolize lactose, a sugar found in milk. For them, eating milk products results in diarrhea, cramps, gas and bloating.

Some food intolerances, such as irritable bowel syndrome, are a result of a digestive tract that doesn’t function well. People with this problem can’t digest foods properly.

Then there are chemical sensitivities. For instance, caffeine, alcohol, chocolate or certain compounds in wine are known to trigger migraines in some people.

There are also inherited conditions, such as G6PD deficiency (favism), in which people lack the enzyme G6PD, which supports the health of red blood cells. For those without this enzyme, eating fava beans leads to the destruction of red blood cells.

A small number of food intolerances involve parts of the immune system – but not the parts connected to allergies. For instance, children with intolerances to certain foods, such as milk, eggs or soy, may suffer an eczema flare-up. Another example is celiac disease. People with this condition have an immune system that attacks the small intestine when they eat gluten, a compound found in wheat, barley and rye.

Food intolerances are more common than true food allergies. Avoiding the culprit food is key to staying well. Treatment depends on what the underlying condition is.

Tips for living with food allergies
• Get tested by an allergist to determine if you have a true food allergy.
• Learn the various names of the foods you're allergic to.
• Read food labels. Call toll-free numbers on food package labels. Ask manufacturers about ingredients and food preparation.
• Avoid foods that "may contain" the food you're allergic to.
• See a dietitian. Get advice on what foods your allergen might appear in and tips on eating out and eating a balanced diet.
• Be cautious in restaurants and at take-out counters. Ask staff about food ingredients and the risk of cross-contamination. For instance, is the same cutting board that's used for fish also being used for non-fish food?
• Always carry your epinephrine auto injector. Learn to use it. Train others how to use it on you, in case you cannot manage.
• Wear a Medic-Alert bracelet.
• Tell family and friends what you're allergic to.
• Get additional information from patient support groups such as Anaphylaxis Canada and the Allergy Asthma information Association.

Read more:
• Canada's 9 most common food allergies
• Winter allergies 411: How to prevent and treat pet and dust allergies
• Food allergies 101
• 6 pet allergy answers

Page 4 of 4