If you answered ‘peanut’, that’s incorrect. But you could hardly be blamed given that legume’s notoriety. The right answer is seafood – from fish to crustaceans and mollusks.

At a time when every “must-try” new restaurant is an over-priced sushi bar, an astounding 2.3 per cent of Americans are now allergic to one form or another of seafood. (There is no such specific Canadian data, but general rates of allergic prevalence are considered comparable.)

If that incidence comes as a surprise, however, you’re in good company. Even the researchers who surveyed 5,500 households for the Food Allergy & Anaphylaxis Network in Virginia and the Mount Sinai School of Medicine in New York to arrive at this finding were taken aback.

“We said, ‘can this be real?”‘ recalls Anne Munoz-Furlong, founder and former CEO of FAAN and co-author of the resulting seafood prevalence study published in 2004. “We learned that shellfish and fish is about double the incidence of peanut and tree nut combined.”

In fact, the researchers reviewed the data to see if something was, well, fishy. But it wasn’t. Those who were accepted as allergic in the detailed phone survey “were very clear in their answers and the symptoms were very clear,” says Munoz-Furlong. Supporting those findings was a 15-nation study that showed similarly high levels of seafood allergies.

Shrimp was the most common cause of reactions in the FAAN-Mount Sinai survey. In fact, shellfish as a group – crustaceans and mollusks – proved by far the larger cul­prit, with 2 per cent of survey participants reporting shellfish allergy while 0.4 per cent reported fish.

Another eye-opening finding was that this is largely an adult phenomenon. The survey found 2.8 per cent of adults were seafood allergic compared to 0.6 per cent of children. And that can be one of the most difficult aspects of this condition – since it strikes grownups, who’ve been eating for years as they pleased, they often don’t know what hit them.

What happened to Chris Oleson is not uncommon. The 41-year-old is a self‑described “beach guy” who lives in San Francisco and grew up surfing on the California coast.

One day in 2002, he was with his wife Julia at an upscale sushi restaurant. He’d eaten about five or six very tasty” items from the trays on offer, when a waiter approached. “Sir, your ears are turning red. You may want to get that checked out,”‘ Oleson recalls him saying.

Oleson was suddenly rather feverish and unwell, but he wasn’t that concerned. He and his wife just thought he was com­ing down with a bug and had better get home. Oleson has asthma, and on the drive home an attack started coming on. He was also feeling woozy when Julia said, “you know, you’ve got hives.”

By the time they got through the door at a nearby hos­pital, Oleson was staggering. He lost consciousness on a stretcher.

There would still be protein traces and no one is suggesting that the one in 50 Americans who are allergic to shellfish (the family that includes shrimp, lobster, clams and crab) begins tucking into a well-boiled chowder.

But the study, published in the Journal of Food Science in January, shows promising results on the possibility of lowering the allergenic properties of shrimp. Tropomyosin (TM) is the main allergen in seafood, including shrimp.

Food scientists have found that boiling shrimp for 10 minutes seems to reduce the  allergenic potency. Researchers compared raw and boiled shrimp that had been ground and freeze-dried and found that the boiled shrimp had fewer allergenic properties than its raw counterpart.

While a far cry from a cure, lead researcher Guang Ming Liu believes the findings are a step in the right direction: “Understanding the allergenic properties of shrimp as affected by the cooking process is critical for shrimp allergic individuals.”

Fish: includes salmon, tuna, cod.
Crustaceans: includes shrimp, lobster, crab.
Mollusks: snails, bivalves (mussels, scallops, oysters), squid.

Cross-Reactions

Within a seafood group …

Dr. Scott Sicherer, author of Understanding and Managing Your Child’s Food Allergies and associate professor of medicine at the Mount Sinai School of Medicine’s Jaffe Food Allergy Institute, concludes from his 2006 review of seafood allergy studies:

- That 30 to 50 per cent of those with an allergy to one of the seafood groups will react to more than one type of fish or shellfish.

However, you can also be allergic to just one type of fish or shellfish. It’s even possible to be allergic to just one type of shrimp.

- That it is common for people to be allergic to more than one shellfish. Sicherer finds up to 80 per cent who are allergic to one crustacean may be sensitized to others, and “40 per cent may react upon ingestion.”

In one study reviewed, blood samples from nine patients with shrimp anaphylaxis reacted to the proteins of 13 crustaceans and mollusks. As well, he finds between 10 and 15 per cent allergic not only to other crustaceans, but to mollusks as well.

- That the risk of reacting to more than one fish is high. Sicherer suggests to speaking to your allergist: “Your allergist may take into consideration the severity of your allergy, test results, and dietary preferences to determine what it is you can and can not eat.”

- That about 50 per cent with a mollusk allergy react to more than one mollusk.

Between shellfish and fish …

According to Sicherer, only about 10 per cent react to both, which have quite different key allergenic proteins (tropomyosin in shellfish; parvalbumin in fish).

Remember, however, that there may be cross-contact between the two groups at grocery seafood counters or in restaurants.

Sources: UpToDate 2006; interview Dr. Scott Sicherer

You may be wide-eyed at the task ahead, but with a little preparation (OK, a lot at first), and maybe a few new tools, you’ll soon be able to make safe, nutritious meals for you and your family.

Yes, you’ve got to read through all those ingredients on food labels. Start with the help of a friend: have one person read the label while the other person checks the list of items to watch for with your allergen. You’ll get the hang of it with a little practice.

Consider too, whether an item may have become contaminated by another item. Did someone use a knife smeared with peanut butter to dig into the jam? It’s not worth it to keep 35 cents worth of jam if there’s a chance of a reaction. Face it, you will throw away food.

Will you keep some allergens in your home for those who don’t have the particular allergy? This is a personal decision that is based in part on necessity, part preference. Can the nutritional requirements of all family members be met on a diet restrictive of all allergens?

Since being prone to allergies in general runs in families, but you don’t inherit specific allergies, some families find that several members have different allergies. To accommodate all, they need to keep some allergens in the home.

If this is the case, special care must be taken to ensure there is no accidental exposure. You can employ:

- Special drink; special cup – Kids love to have their own special items. Having a cup for each child means they won’t drink from the wrong cup by mistake.

- Be alert when handling dangerous foods! Some parents have been known to implement rules such as: “No white liquids when Mommy is tired.” Keeping foods in different looking containers is helpful. If you purchase your soy milk by the carton, consider buying milk by the bag.

- Color code – This is great for the young child who can’t read but has mastered colors. A system of green (OK) and red (not OK) dot stickers works well. They can quickly find a safe snack by themselves and you have a built in system for recognizing which food is safe for whom.

- Label – Storing foods side-by-side can increase the risk of contamination by spills. A plastic container kept in the fridge and labeled with the individual’s name is a handy way of avoiding this issue. Babysitters will appreciate a container full of safe snacks in the cupboard that can be given out. Keep some safe foods at levels the children can reach and store allergens up out of reach.

Next: Safe Kitchen Gear

Does your child refuse to eat a certain food, or complain that it makes his “tongue hurt”? These could be signs of a food allergy, and should be taken seriously.

It is common for the symptoms of food allergy to vary by individual – and from reaction to reaction in the same person. Not everyone will get all the symptoms, which range greatly in severity from mild to severe (and even fatal): your throat may feel tight on one exposure to your allergen or you may get itchy hives on your skin and vomiting with the next.

The Range of Symptoms

-Tingling in the mouth
-Swelling of the tongue and throat / feeling of throat tightness
-Itchy skin, hives or skin redness
-Abdominal cramps
-Vomiting or diarrhea
-Breathing difficulty, wheezing
-Faintness due to a sudden drop in blood pressure

Anaphylaxis

Anaphylaxis is the severe form of allergic reaction. It involves one or more of the body’s symptoms; for example, the gastrointestinal tract, the respiratory tract, the skin and the cardiovascular system. A person experiencing anaphylaxis often has difficulty breathing, and the person could lose consciousness. Anaphylaxis puts a person at risk of death.

Anaphylactic reactions can come on quickly, and it’s impossible to know when a reaction will become severe. It’s important that people with food allergies are prepared for a reaction by always carrying an epinephrine auto-injector (either EpiPen or Twinject).

Experts recommend using epinephrine early if a person known to be at risk of anaphylaxis begins to show signs of allergy symptoms – don’t wait until the symptoms worsen, as it may become to difficult put a halt to the reaction once it’s in progress.

Symptoms reviewed by Dr. Susan Waserman

Label Aware – Fish and Shellfish Allergy

Reading labels is a way of life when you have fish or shellfish allergies. Before eating anything in a package, be sure to read the label carefully. Look for hidden sources of fish or shellfish and other names for fish or shellfish.

Also be on the lookout for precautionary statements. These are statements that indicate an allergen may be in the food, due to cross contamination during processing. Examples of precautionary statements include: “May contain fish” and “Manufactured in a facility that also processes shrimp and crab.”

Allergists generally advise people with fish or shellfish allergies to avoid all products that include precautionary statements about their allergen.

If you are ever uncertain about whether a food product is safe for you, call the manufacturer to confirm. When in doubt, don’t eat it.

In Canada, new regulations (2012) require food manufacturers list priority allergens in plain language on packaging, rather than using rarely known specific names – ie. tarama or orange roughy (fish) or quahaugs (shellfish). The ingredients within listed ingredients that are priority allergens would also have to be shown. For example, manufacturers couldn’t simply list “gelatin” if the source of the gelatin is a priority allergen, such as fish.

More on Canada’s 2012 Food Allergen Regulations.

In the United States, the Food Allergen Labeling and Consumer Protection Act went into effect in 2006. FALCPA requires manufacturers to use plain language when listing the top 8 priority allergens, and to declare all allergens either in the ingredient list, or in a “Contains:” statement at the end of the list.

The allergens included in this regulation are milk, eggs, fish, shellfish, tree nuts, wheat peanuts and soybeans. The Canadian regulations also add sesame and mustard as priority allergens, while separate legislation requires companies to declare sulfites if they are present at more than 10 parts per million, or if they had a technical or functional effect in the food.

Both the United States and Canada are studying ways to regulate the precautionary statements used on packaged food labels.

Fish allergy is less common, affecting 0.18 per cent of children and 0.56 per cent of adults.

In general, food allergy is on the rise in North America and other developed countries In Canada, an estimated 7.5 per cent of people have food allergies, representing more than 2.5 million people. In the United States it’s estimated that 12 million Americans (or just under 4 per cent of the population) have food allergies.

A major study in the United States recently found that cases of peanut allergy in children more than tripled in a decade, and that more than 3 million Americans now have a peanut or nut allergy.

Here are the rates of some of the major allergens in Canada and the U.S.

CANADA

Source: Surveying Canadians to Assess the Prevalence of Common Food Allergies and Attitudes towards Food LAbelling and Risk (SCAAALAR) study. Published in the Journal of Allergy and Clinical Immunology, June 2010.

UNITED STATES

Peanut, Tree Nut or both:
Children -  2.1 %
Adults – 1.3 %

Source: US prevalence of self-reported peanut, tree nut, and sesame allergy: 11-year follow-up. Published in the Journal of Allergy and Clinical Immunology, June 2010.

Milk and egg allergy are both common in children. In the United States, 2.5 per cent of children under the age of 3 have a milk allergy. Egg allergy affects 1.5 to 3.2 per cent of children.

The good news is many children outgrow their allergies to milk and egg. Research shows 80 per cent of milk allergy is outgrown by age 16, while 68 % of egg allergy is outgrown by that age.

Source: AAAAI