Finding Out More About Food Allergies

Our immune system is designed to protect our body from harmful invaders, such as bacteria. Sometimes, however, the system responds to substances normally considered harmless. The substance that provokes the attack is called an allergen; the substances that attack the allergen are called antibodies. A food allergy can provoke such a response as your body releases antibodies to attack specific proteins in food. When this happens, some of the physical reactions include:

• Hives
• Itching
• Swelling of the face, tongue, lips, eyelids, hands, and feet
• Rashes
• Headaches, migraines
• Nausea or vomiting
• Diarrhoea, sometimes bloody
• Sneezing, coughing
• Asthma
• Difficulty in breathing caused by swelling of tissues in the throat
• Loss of consciousness

If you are sensitive to a specific food, you may not have to eat the food to have the reaction. For example, people sensitive to peanuts may break out in hives just from touching a peanut or peanut butter and may suffer a potentially fatal reaction after simply tasting chocolate that has touched factory machinery that previously touched peanuts. People sensitive to seafood-fin fish and shellfish-have been known to develop breathing problems after simply inhaling the vapours or steam produced by cooking the fish.

How an allergic reaction occurs

When you eat a food containing a protein to which you’re sensitive, your immune system releases antibodies that hitch a ride on white blood cells called basophils. The basophils circulate through your entire body, giving the antibodies the chance to hop off and bind to immune system cells called mast cells.

Basophils and mast cells produce, store, and release histamine, a natural body chemical that causes the symptoms-itching, swelling, hives-associated with allergic reactions. Yes, that’s why some allergy pills are called antihistamines. When the antibodies carried by the basophils and mast cells come in contact with food allergens, boom! You have an allergic reaction.

Two kinds of allergic reactions

Your body may react to an allergen in one of two ways-immediately or later on:

• Immediate reactions are more dangerous because they involve a fast swelling of tissue, sometimes within seconds after contact with the offending food.
• Delayed reactions, which may occur as long as 24 to 48 hours after you’ve been exposed to the offending food, are usually much milder, perhaps a slight cough or nasal congestion caused by swollen tissues.

Foods Most Likely to Cause Allergic Reactions

Here’s something to chew on: More than 90 percent of all allergic reactions to foods are caused by just eight foods:

• Milk
• Eggs
• Peanuts
• Tree nuts
• Soybean-based foods
• Wheat
• Fish

Coping with Food Allergies

After you know that you’re allergic to a food, the best way to avoid an allergic reaction is to avoid the food. Unfortunately, that task may be harder than it sounds because the offending ingredient may be hidden-peanuts in the chili or caviar (“fish eggs”) in the dip.

Sometimes the “hidden” ingredient is hidden in plain sight on a food label that uses chemical code names for allergens. If you’re someone with a potentially life-threatening allergy to food (or another allergen, such as wasp venom), your nutritionist may suggest that you carry a syringe pre-filled with epinephrine, a drug that counteracts the reactions.