The $4.3 billion global market for gluten-free foods is feeding on a myth of gluten sensitivity that could actually be hurting people with genuine allergies, a new analysis says.

“This could be dangerous,” Dr. Gino Roberto Corazza said in an interview with the Annals of Internal Medicine that accompanied the analysis he and Dr. Antonio Di Sabatino did.

“Self-prescription of gluten withdrawal inevitably leads to a series of problems,” he said.

Among them: missing a genuine diagnosis of serious but rare celiac disease, eliminating the nutrients from gluten for the wrong reasons and spending more money than necessary for more expensive gluten-free products.

“We must prevent a possible health problem from becoming a social health problem.”

Gluten is a complex protein found in wheat, barley and rye that causes an immune reaction in people with celiac disease, about 1 per cent of the population.

Only one full-scale medical study over the last 30 years has tested for non-celiac gluten sensitivity, so no one actually knows how widespread it is, the doctors at the University of Pavia in Italy said.

In the meantime, U.S. sales of gluten-free food have more than doubled since 2005 to more than $1.5 billion, the market research company Packaged Facts reported in 2010.

Celebrities such as Gwyneth Paltrow, Victoria Beckham and Old Spice Guy Isaiah Mustafa have embraced the diet. At least two Toronto restaurants, Kensington Cornerstore and Around the Corner, are gluten-free.

People with gluten sensitivity can develop stomach cramps, boating, flatulence and diarrhea or lethargy, headaches or hyperactivity disorder.

But, said Corazza, those symptoms could be a lot of other things that could be better treated with something other than a gluten-free diet. In fact, a wheat sensitivity would be different from a gluten sensitivity.

“I think the number is much less” of people with actual gluten sensitivities than assumed, Corazza said.

Of gluten sensitivity, he said, “I think it is real” but “we are not able to classify it with any certainty” because of the lack of scientific studies.

“We have tried to convince doctors to start studying this.” But double-blind, placebo-controlled studies, particularly of volatile food sensitivities, are expensive and time-consuming.

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Of the 4,598 references to non-celiac gluten sensitivity in Google, there is one among the studies in PubMed, a medical journal site, making it a far higher ratio than for breast cancer, Alzheimer’s disease, lung cancer or celiac disease itself, the doctors’ analysis said.

The Washington Post in 2011 said research suggested there were 17 million gluten-sensitive people in the United States and 3 million with celiac disease.