Non-celiac gluten intolerance: fact or fiction?

Non-celiac gluten intolerance: fact or fiction?

With so many people now on gluten-free diets, a look at some recent research

By Kurt Ullman

Although there has been scant proof of effectiveness, gluten-free diets are becoming widely prescribed for even those without celiac disease. A new study recently published in the American Journal of Gastroenterology suggests that non-celiac gluten intolerance may exist.

“It is estimated—and estimation is all we can rely on—that up to 90% of people following a gluten-free diet (GFD) do not have celiac disease, and that as many as 15% of the population suffer from ‘gluten intolerance’,” says Jessica Biesiekierski, PhD, from the Department of Medicine and Gastroenterology at Box Hill Hospital in Melbourne, Victoria, Australia. “The target of our research was to conduct an experiment where the effect of gluten (that is free from carbohydrates including fructans) was evaluated in patients with irritable bowed syndrome (IBS) where celiac disease had been definitively excluded via histology or genotyping. We wanted to identify whether such an entity as non-celiac gluten intolerance actually (NCGI) exists.”

The study was a double-blinded, randomized, placebo-controlled rechallenge trial in 34 patients with IBS without celiac disease who were symptomatically controlled on a GFD. They were given either gluten (16 grams) or placebo (0 grams of gluten) in the form of two slices of bread and one muffin per day with a GFD. Participants receiving the gluten treatment arm had a significantly greater change in severity of GI symptoms after just one week of therapy, especially for overall gastrointestinal symptoms, gut pain, bloating, wind (flatulence), satisfaction with stool consistency, and tiredness when compared to the placebo group.

Of 19 patients in the gluten group, 13 (68%) reported that symptoms were not adequately controlled compared to 6 of 15 (40%) on placebo (P = 0.0001; generalized estimating equation). On a visual analog scale, patients were significantly worse with gluten within one week for overall symptoms (P = 0.047), pain (P = 0.016), bloating (P = 0.031), satisfaction with stool consistency (P = 0.024) and tiredness (P = 0.001). Anti-gliadin antibodies were not induced. No significant changes were seen in fecal lactoferrin, levels of celiac antibodies, highly sensitive C-reactive protein, or intestinal permeability.

“We just have to be careful that the GFD’s growing popularity doesn’t negate the seriousness of the situation for people with celiac disease, and [that] patients aren’t going gluten free without consulting a doctor first for celiac screening,” said Ms. Biesiekierski. “Until the unanswered questions of mechanism can be answered and the results can be repeated, we should have an awareness that gluten may indeed trigger gut symptoms in non-celiac patients.”

The Helen Macpherson Smith Trust and the National Health and Medical Research Council of Australia supported this study. The only direct competing interest reported was that one of the participants has published cookbooks related to celiac disease.

Source: Biesiekierski JR, et al. Gluten causes gastrointestinal symptoms in subjects without celiac disease: A double-blind randomized placebo-controlled trial. Am J Gastroenterol. 2010;106:508-514).