The president of the Quebec chapter of the Canadian Celiac Association, Louise Pearl, says while a gluten-free diet trend means more options for people with an intolerance, it can be dangerous for those with celiac disease. 

"There are people who see an opportunity to widen their customer base without really knowing how to do it safely," says Pearl. "Those of us with celiac disease cannot tolerate any cross-contamination of gluten in the food we eat." 

Health Canada estimates that as many as 300,000 Canadians may have celiac disease — an autoimmune disease that occurs when people who are genetically susceptible eat gluten, a protein found in certain grains including wheat, rye, and barley. 

Pearl says new labelling rules introduced by Health Canada in August 2012 helped those with celiac disease better navigate the product labels in the grocery store, but she says there is still too much uncertainty at restaurants. 

Dr. Terry Sigman's tips for diners with celiac disease:

 - Call the restaurant ahead and speak to a manager

 - Ask about how the food is prepared, including the dishes and utensils used

 - Ask about the content of the sauces and spices used 

Pearl, who also owns the gluten-free grocery store and bakery Louise Sans Gluten, says customers routinely complain about falling ill after eating gluten-contaminated foods at Montreal restaurants. 

"If you're going to make a claim of some sort on the food you're producing, you must deliver. This isn't just about, 'Oh I'll get an upset tummy.' It's way beyond that," says Pearl. 

Pediatric gastroenterologist Dr. Terry Sigman says consuming even small amounts of gluten can cause internal damage in people with celiac disease, even if they don't present any symptoms. 

"The damage could lead to many things, and the thought is that eventually it could lead to ongoing chronic damage to the intestine which can increase your risk of malignancy in the future – so lymphoma of the small bowel," says Dr. Sigman.

Eating gluten-free in Montreal

After years of discomfort, Kristen Oliver, 30, discovered she had celiac disease ten years ago.

Kristen Oliver

Kristen Oliver, 30, cooks the majority of her meals at home, where she is certain there is no cross-contamination with gluten-containing foods. (Morgan Dunlop/CBC)

"I would have more than 10 large canker sores at a time. I couldn't eat. It would hurt to chew. I would get headaches. I wasn't able to go to school certain days because I was in so much pain," she says.

At first, Oliver considered the ever-increasing gluten-free options a welcome bonus. But her concern set in when she found she began falling ill after eating restaurant meals billed as gluten-free.  

For Oliver, inadvertently consuming gluten means three days of staying in bed with an upset stomach and so little energy that it's a struggle to walk to the kitchen and prepare a cup of tea. After such an episode, she suffers from mental and physical exhaustion for weeks.

"I try to be positive about it and not have a negative outlook of celiac disease," she says. "But it's extremely frustrating when you have to miss work and not live your life fully for three weeks."