It wasn't that long ago that harried parents would send their kids off to school with lunch boxes filled with a peanut butter and jam sandwich or two, an apple, a juice box and maybe a couple of cookies.

Times have changed. And not always for the better.

While greater awareness of food allergies has cut into the proliferation of peanuts and nut-based products in schools, there are a host of foods that can cause serious — even life-threatening issues for some children.

On Sept. 30, 2003, doctors at the Children's Hospital of Eastern Ontario in Ottawa removed 13-year-old Sabrina Shannon from life support. A day earlier she suffered anaphylactic shock after eating french fries in her high school cafeteria.

Shannon knew of her allergies and was diligent in making sure that the food she ate was safe. She was at risk of anaphylaxis to peanuts, dairy products and soy.

Shannon had eaten fries at the cafeteria once before, after checking to make sure that they were not fried in peanut oil. What proved deadly was the tongs used to serve the fries. They were also used to serve poutine, coming in contact with cheese. Cross-contamination killed the young student.

Almost three years later, the Ontario government passed a law — dubbed Sabrina's Law — that requires schools across the province to ensure that they have an emergency plan in place to deal with anaphylaxis.

It requires principals to implement plans that include:

• Strategies to reduce exposure to allergens.
• Procedures to communicate to parents, students and employees about life-threatening allergies.
• Regular training on dealing with life-threatening allergies for teachers and staff.

Hanna Carter, 5, of Roanoke, Va., takes a dosage of peanut protein as treatment for peanut allergies. A handful of children once severely allergic to peanuts now can eat them without worry. Scientists have retrained their immune systems so they're allergy-free. (Gerry Broome/Associated Press)Principals must also have plans in place for each student at risk of anaphylaxis, keep a file that lists prescriptions and emergency contacts for all students at risk, and ensure that parents supply information on their children's allergies.

The legislation has been seen as a model for other North American jurisdictions. It aims to make schools as safe as possible for students with severe allergies. It does not necessarily turn them into peanut-free zones.

The Toronto District School Board appeals to parents to keep their children's lunches and snacks free of peanuts and nuts under Operation Procedure PR563: Anaphylaxis. The Calgary Board of Education aims to "minimize the risk of exposure of students with severe allergies … without depriving the student with severe allergies of normal peer interactions or placing unreasonable restrictions on the activities of other students in the school."

More than just nuts

But it's not just peanuts and nuts that students and teachers need to be aware of. There are other food sensitivities that can lead to issues for some people.

It's estimated that approximately one per cent of the population is living with celiac disease. That's five times the number that was diagnosed in the 1950s.

People with the condition can't tolerate gluten, which is a protein found in wheat, rye, triticale, and barley. In flour, gluten helps bread and other baked goods bind. It prevents crumbling. However, gluten damages the absorptive surface of the small intestine in people with celiac disease, preventing them from absorbing nutrients essential for good health.

There's no cure, but following a gluten-free diet enables people with celiac to live healthy lives.

The level of intolerance can vary. Eating food that contains gluten won't cause anaphylactic shock. However, it will cause discomfort as the digestive system is unable to break down the food.

Common symptoms of celiac disease include anemia, chronic diarrhea, weight loss, fatigue, cramps and bloating, irritability.

People with the condition have to be very careful about what they eat: they need to read the labels on all products they consume, to make sure they don't contain ingredients that include gluten.

Things that other students take for granted — pizza days, birthday cakes and cookies — are off limits for people who can't tolerate gluten.

There are steps that parents of children with gluten intolerance can take, including:

• Talking to teachers and lunchroom supervisors: they need to know it's not a good idea for your child to trade food.
• Giving your child's teacher a stash of gluten-free treats. It will help your child feel included when the rest of the class is enjoying treats your child can't eat.
• Bringing in a popular gluten-free treat for the entire class for your child's birthday.

Healthier snacks?

Of course, you could avoid worrying whether what you're packing in your kid's lunchbox will trigger an allergic reaction in other kids by loading up on fruits and vegetables.

Maybe not.

Some people living with hayfever may have another issue to deal with: oral allergy syndrome. It's an allergic reaction to certain proteins in fruits, vegetables and nuts that most often afflicts people allergic to birch pollen. It may also be a problem for people allergic to ragweed and grasses.

Symptoms include:

• Itching and burning of the lips, mouth and throat.
• Watery, itchy eyes.
• Runny nose.
• Sneezing.
• Rash, itching and swelling where the food touches the skin.

Symptoms usually develop right after eating fruits like apples, cherries, peaches and plums or vegetables including beans, carrots, celery, green peppers and tomatoes.

In some cases, touching the skin of certain fruits or vegetables is enough to set off a reaction. The symptoms usually go away on their own, especially after drinking water. In rare cases, severe reactions have been reported including anyphalactic shock.

People with oral allergy syndrome react to raw fruits or vegetables. Cooking fruits or vegetables destroys the protein present in the raw food that some people react to.

The condition also is not common among younger children with hayfever. It usually affects older children and adults.