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Gluten-free diets: Where do we stand?

3/6/2017, 6 a.m.
Over the past few decades, millions of people around the world have distanced themselves from gluten, eliminating gluten sources from ...

— Why exactly can gluten make those with celiac sick? Scientists originally viewed it as a food allergy, but that all changed in the decades to come.

1970s: The genetics unfold

Scientists uncovered the first signs that celiac disease could be an autoimmune disorder -- instead of an allergic one -- in the 1970s, Leffler said.

The pathogenesis, or how the disease develops on a cellular level, first appeared in the scientific literature. By the mid- to late 1970s, many studies had been published on the pathogenesis of the disease, linking celiac disease with immunological disorders.

Leffler said that those studies would lead to the discovery that celiac disease was associated with a gene called HLA-DQ2, a component of the genetic immune response. The HLA-DQ8 gene is also associated.

"This was sort of a surprise, because HLA-DQ2 was already known to be linked to type 1 diabetes, which is another classic autoimmune disease, but not to any of the allergic diseases. So the genetics that people with celiac disease have is much more similar to autoimmune diseases," Leffler said.

Scientists realized that celiac disease is an autoimmune disorder, spurring the immune system to attack its own intestines when gluten enters the body.

It was still thought that only people with celiac disease could have such reactions to gluten, but then the idea emerged that gluten could impact the health of some people without celiac disease, too.

1980s: What is non-celiac gluten sensitivity?

"The new kid on the block is gluten sensitivity or the so-called non-celiac gluten sensitivity," said Dr. Anca Safta, assistant professor and pediatric GI section head at Wake Forest Baptist Medical Center in North Carolina.

A description of non-celiac gluten sensitivity was originally published in a 1980 paper in the journal Gastroenterology. The paper described eight women who suffered abdominal pain and chronic diarrhea that went away while they were on a gluten-free diet. They had no evidence of celiac disease, based on biopsies. Currently, celiac disease may be diagnosed based on your medical and family history, a physical exam, blood test, genetic test, or a skin or intestinal biopsy.

However, Safta said that since non-celiac gluten sensitivity is still new to the scientific literature, much confusion remains around it as a medical condition. For now, non-celiac gluten sensitivity is viewed as a condition that has the same symptoms of celiac disease but without the immune system damaging the intestines.

"The symptoms are there. Folks do get better once they remove the gluten-containing products, and the very important thing is to exclude celiac disease from the picture, as celiac disease implies that the intestinal mucosa has suffered damage," Safta said.

"As we're learning more, we don't even know if we have the correct nomenclature for non-celiac gluten sensitivity," she said. "It might not be gluten that is causing this non-celiac gluten sensitivity, and it might be a different protein found in wheat, but because of the exclusion of the gluten-containing products for symptoms to improve, that's why it's kind of gotten the name of non-celiac gluten sensitivity."