Allergy Q&A: 10 Need-To-Know Facts

Imagine questioning yourself at every bite of every meal every day. For millions of Canadians who suffer from food allergies, this is the reality. By learning more about allergies, we can protect ourselves and our loved ones, and keep everyone happy and healthy.

A person with food allergies is always on high alert, not just at mealtimes.

One of my brothers is dangerously allergic to nuts, legumes and seafood. The whole family has had to develop new habits to keep him safe. Just for nuts alone, we have to ask: Has the slicer at the bakery been used to cut nut bread? Is that cake filled with hazelnut praline or covered in almond paste? Are there pistachios in the snack bowl? Now imagine the number of questions at a restaurant! It can be quite the ordeal. To clear up facts and debunk myths, we’re answering the top 10 most frequently asked questions about food allergies.

1.How much exposure is needed to cause a reaction?

The tiniest trace of a substance – even if it’s invisible to the naked eye – can trigger a reaction. Allergic reactions can affect your skin (hives, eczema); cause swelling of the face, lips, tongue, throat; trigger digestive issues; lower your blood pressure and increase your heartbeat. In extreme cases of allergic reactions, a person may experience anaphylaxis, which might mean shock, loss of consciousness or even death. Some reaction times are very quick (within seconds of ingesting the allergen), while others can take up to a few hours.

2. Can someone be allergic to any food?

Yes. An allergy is your immune system’s response to a protein or an irritant. Health Canada has identified over 160 foods that have triggered allergic reactions in the population. Of those, the following 10 are considered “priority food allergens,” meaning they cause the majority of reactions.

  1. Peanuts
  2. Tree Nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios and walnuts)
  3. Soy
  4. Seafood (fish, crustaceans and shellfish)
  5. Cow's milk
  6. Eggs
  7. Wheat
  8. Sesame Seeds
  9. Mustard
  10. Sulphites (a food additive)

Avoiding cross-contamination

How can you be sure that the pecans haven’t touched the peanuts, or that the almonds weren’t processed in a plant that handles hazelnuts? Unless otherwise clearly indicated on the packaging, there’s no way to be sure. Your safest bet is to assume that shelled tree nuts have come into contact with each other, and with peanuts. But whole nuts are a different story! Buy them with the shells on, wash them in slightly soapy water, open them and roast them in the oven for 20 minutes at 325°F (170°C), and you should be fine.

One other thing to remember is that the “May contain traces of...” warning on packaging is placed there voluntarily by manufacturers. The absence of the warning doesn’t mean there’s no risk of contamination. Better safe that sorry in these cases! That said, a CAC (Certified Allergen Control) certification on the package means that the company has passed strict checks, and that there’s no chance of cross-contamination from almonds, peanuts, milk or eggs. And some companies, like Blue Diamond, ensure that their nuts are processed and packaged in peanut-free factories.

3. Can you overcome a food allergy?

In the majority of cases, children grow out of their allergies (including milk, wheat and eggs) before age 7. Unfortunately, allergies to peanuts persist after that age in about 80% of cases. The only solution is to steer clear of the food you’re allergic to (which is easier said than done). People with severe food allergies should always carry an auto-injector device (like an EpiPen or the new credit card-sized Allerject).

4. Does an allergy to peanuts automatically mean an allergy to other nuts?

No. Despite their name, peanuts are legumes, so there’s no need to eliminate tree nuts from your diet. Other legumes, like dry beans, lentils, soy and chickpeas, don’t always cause problems for people with peanut allergies, with between 5 and 10% of people having reactions to several foods in this family. That said, cross-contamination between peanuts and tree nuts is common and can be extremely dangerous.

5. Eating a peach, kiwi, apple or melon makes my throat tingle. Am I allergic to those fruits?

It may be that you’re experiencing pollen-food allergy syndrome, also known as oral allergy syndrome. Proteins in some foods are very similar to pollen proteins, confusing the body into reacting to the food the way it would to the pollens. It’s especially common in people who suffer from hay fever. The chart below shows the link between certain pollens and certain foods.

Foods most often associated with birch, ragweed, grass and wormwood allergies.

An allergy to this type of pollen…

Birch can cause a reaction to the following foods:

  • Fruits: apple, apricot, cherry, kiwi, nectarine, peach, pear, plum, tomato
  • Vegetables: anise, bean, caraway, carrot, celery, coriander, cumin, dill, fennel, green bell pepper, lentil, parsley, parsnip, peanut, pea, potato
  • Nuts: almond, hazelnut, walnut
  • Seeds: sunflower

An allergy to this type of pollen…

Grass can cause a reaction to the following foods:

  • FRUITS: kiwi, melon, orange, tomato, watermelon

An allergy to this type of pollen…

Wormwood can cause a reaction to the following foods:

  • FRUITS: apple, melon, watermelon
  • VEGETABLES: carrot, celery

An allergy to this type of pollen…

Ragweed can cause a reaction to the following foods:

  • FRUITS: banana, cantaloupe, honeydew, watermelon
  • VEGETABLES: cucumber, zucchini

Generally, pollen-food allergy syndrome causes a reaction when fruits and vegetables are eaten raw. Contact with the peel can increase the severity of the reaction, while storage for a certain amount of time can minimize the effects. Cooking and canning often modifies the proteins’ structure enough to solve the problem, except with nuts and celery that, for many, continue to cause reactions even once cooked. In most cases, symptoms disappear soon after the fruit or vegetable has been swallowed, but caution is always recommended as there have been reports of severe generalized reactions.SOURCE: Canadian Food Inspection Agency

6. How can I know if pre-packaged foods have come in contact with an allergen?

New legislation about labelling foods has made this much easier. Since August 2012, all pre-packaged food and alcoholic beverages (except beer) must indicate the presence of any of the top 10 allergens, as well as gluten, using one of these two methods.

  • Indication on the package that the product may contain an allergen; or
  • Clearly listing the allergen in the ingredient list. For example, rather than just “lecithin,” the source (like soy) must be included. As if casein is listed as an ingredient, the presence of dairy must be clearly indicated.

Basically, any shortcuts or general terms that could hide the presence of an allergen are banned. So instead of writing “seasoning” in an ingredient list, manufacturers have two options. They can place the allergen in parentheses next to the ingredient: “seasoning (mustard),” or they can write “Contains mustard” on the packaging.

7. Do I have to read the packaging every time I buy a product, even if I’ve bought it before?

Absolutely. “A manufacturer can change the recipe for its product without warning the consumer,” explains nutritionist Stephanie Pernice, a food allergy expert. “Also, depending on the format or size, products might be made on different assembly lines or even in different factories. It’s essential to read the ingredient list of a packaged food, even if you’ve been buying it for years.”

8. Can the smell alone of a food provoke an allergic reaction?

Yes, but it’s rare. To trigger a reaction, an allergen protein has to enter your body. There are certain instances when the proteins become airborne, like at a seafood restaurant or in a factory that processes ingredients like almond and nut powders, soy flour or powdered milk. The aromatic particles of food alone (like the smell of peanut butter) are usually harmless.

9. Can touching an allergen cause a reaction?

The skin is a highly effective barrier that prevents allergens from entering the bloodstream. To trigger an allergic reaction, you would have to touch an allergen then touch your eyes or mouth, kiss someone on the mouth or press the allergen to an open wound. Otherwise, a skin reaction should be very minimal, if there is one at all.

10. What can I say to people who think my allergic child is just being a picky eater?

As someone with food allergies herself, Stephanie has a clear answer: “In children and adults alike, food allergies have an impact on your social life. You can certainly live with food allergies but there are restrictions. And no parent would impose those restrictions on their child just for fun. People who think food allergies are a mere whim don’t realize the potential impact of seemingly innocuous foods. Think of the hassle of avoiding dairy when you’re taking antibiotics – and that’s just for a few days! A food allergy is a serious condition and a reaction can be dangerous, even with trace amounts of the food.”


Hélène Laurendeau

A nutrition and health enthusiast who loves to share: this description fits Hélène Laurendeau to a tee. She has been active for more than 25 years in the media and communications field. Nutritionist, host, columnist, author and speaker, Hélène holds a Bachelor degree in Nutrition and a Master degree in Epidemiology. She has spread her knowledge alongside Ricardo every week since 2005, as part of his daily show broadcast on ICI Radio-Canada Télé, as well as in Ricardo magazine, where she pens the Bien se nourrir (Eating Well) column.