Re: Gluten elimination diets

Drs Cadenhead and Sweeny state that “there is no need for patients to avoid gluten unless they have celiac disease, or to avoid wheat unless they have IgE antibody-mediated wheat allergy” and imply that the rest of the patients who think they have gastrointestinal symptoms that are improved on a gluten-free diet are simply following a fad and should be advised to include wheat in their diet [“Gluten elimination diets: Facts for patients on this food fad,” BCMJ 2013;55:161].[1]

Although I do not doubt that faddism explains a large part of the surging popularity of gluten-free diets, I think this is an oversimplification of the matter and was surprised that Drs Cadenhead and Sweeny did not mention the literature about non-celiac gluten intolerance. Studies suggesting the existence of non-celiac gluten sensitivity have been published over the past several years, and last year a consensus document published by international experts recommended that non-celiac gluten sensitivity be recognized alongside celiac disease and wheat allergy as one of three gluten-induced conditions.[2]

A small 2011 study recruited 34 patients who self-identified as having irritable bowel syndrome (IBS) symptoms that had resolved with a gluten-free diet and in whom celiac disease had been ruled out; these patients were randomized to receive gluten or placebo in the form of bread and muffins, and the patients who received gluten experienced worse symptoms (including pain, bloating, and tiredness).[3] 

More recently, a much larger study was conducted with a double-blind, placebo-controlled crossover design.[4] A total of 920 patients with IBS symptoms and without celiac disease un­derwent a 4-week elimination diet (excluding wheat, cow’s milk, eggs, tomato, chocolate, and any other known food hypersensitivities). This was followed by a 2-week crossover trial—2 weeks of capsules with wheat followed by 1 week of washout and then 2 weeks of capsules with xylose, or the reverse. Results showed that 276 patients (30%) had significantly worse IBS symptoms with wheat, and none experienced worsening of symptoms with placebo.

Some authors recommend that at this juncture it is appropriate for phy­sicians to test patients who report be­ing sensitive to gluten for both celiac disease and wheat allergy, and if both are negative, to advise patients that they likely have a non-celiac gluten sensitivity, which is “a newly recognized clinical entity for which we do not yet fully understand the natural course or pathophysiology.”[5]

The gluten-free diet controversy provides an excellent case for thinking about how we communicate with our patients—there are some aspects of the issue that we understand well, some that are controversial and in­volve changing evidence, and there is great deal of misinformation about the issue within in the public realm. 

The gluten-free diet issue also highlights another important point for physicians to bear in mind when communicating with patients: what is dogma today may be called into question by new evidence tomorrow. If all that we tell patients is “there is no need for pa­tients to avoid gluten unless they have celiac disease, or to avoid wheat un­less they have IgE antibody-mediated wheat allergy,” I would argue that we might do a disservice to patients in two ways. First, the patient may have symptoms that improve with a modified diet (i.e., non-celiac gluten insensitivity). Second, we risk harming the therapeutic alliance we have with our patients by discounting their experience. 

That said, simply telling the patient that they “likely” have non-celiac gluten sensitivity (as recommended by Aziz and colleagues[5]) might be overstating the probability of the patient having this condition for, as Cadenhead and Sweeny point out, there is a good chance that the patient has made multiple changes in their diet simultaneously, which can confuse the picture. Therefore, discussing the state of the evidence and recommending trial elimination diets with food and symptoms diaries, followed by reintroducing food challenges, is likely a more productive approach.
—Judith Hammond
UBC Medical Student Class of 2013

References

1.    Cadenhead K, Sweeny M. Gluten elimination diets: Facts for patients on this food fad. BCMJ 2013,55:161.
2.    Sapone A, Bai JC, Ciacci C, et al. Spectrum of gluten-related disorders: Consensus on new nomenclature and classification. BMC Med 2012;10:13.
3.    Biesiekierski JR, Newnham ED, Irving PM et al. Gluten causes gastrointestinal symptoms in subjects without celiac disease: A double-blind randomized placebo-controlled trial. Am J Gastroenterol 2011;106:508-514.
4.    Carroccio A, Mansueto P, Iocono G, et al. Non-celiac wheat sensitivity diagnosed by double-blind placebo-controlled challenge: Exploring a new clinical entity. Am J Gastroenterol 2012;107:1898-1906.
5.    Aziz I, Hadjivassiliou M, Sanders DS. Does gluten sensitivity in the absence of coeliac disease exist? BMJ 2012;345:e7907.