In Canada, even people with Celiac disease don't really think of it as a disease, so it's no surprise the more subjective gluten "intolerance", which food marketers have used to create a $5 billion industry south of the Canadian border, is basically unknown. 

Efforts to manufacture concern have not helped. A few months ago, a group tried to get more attention for gluten issues, so they examined blood work of almost 3,000 Canadians and found that one in 114 (just under one percent, the same as elsewhere) had elevated antibodies that indicate they suffered from celiac disease, which causes gastric distress and other symptoms. Yet almost 90 percent of those did not feel like they had a disease. 

The data were collected about a decade ago, before the gluten-free fad took off.

What conclusions have been people drawn from the fact that only 1 in 1,000 Canadians feel like they have a gluten sensitivity issue even if they do? That it's a Caucasian disease, even though the genetic variant that is linked to higher risk for celiac disease is as high in South Asian samples as Caucasian ones. 

How do people not know they have it? Unlike lactose, symptoms are not common and since gluten causes damage to the intestinal lining over time, symptoms are often not acute. Adding to the confusion is that 75 percent of people who claim some kind of gluten sensitivity show no reaction of any kind biologically. Most who claim they are on a spectrum of gluten sensitivity are not feeling better because gluten ever made them feel worse, it is instead that they stopped eating heaping servings of pasta, white bread and other sources of carbohydrates.