People with non-celiac gluten sensitivity may not be reacting to gluten at all -- instead, they may be getting some of their symptoms from some other component in wheat, or possibly from a type of carbohydrate molecule found in wheat but also in other foods, according to a new study. The study, published in the journal Gastroenterology, concluded that people with self-reported gluten sensitivity didnt experience symptoms during a gluten challenge after they had eliminated foods high in carbohydrate FODMAPs -- fermentable, oligo-, di-, monosaccharides and polyols -- from their diets. At face value, the study seems to question the existence of non-celiac gluten sensitivity: In a placebo-controlled, cross-over rechallenge study, we found no evidence of specific or dose-dependent effects of gluten in patients with NCGS [non-celiac gluten sensitivity] placed on diets low in FODMAPs, the authors wrote. However, the truth could be much more complicated. This study does not mean gluten sensitivity doesnt exist, Dr. Alessio Fasano, head of Massachusetts Generals Center for Celiac Research and a top gluten sensitivity researcher, told me in an interview. But it may show that the symptoms are not due to the gluten component in wheat. Some researchers have speculated that symptoms in irritable bowel syndrome can be triggered by foods high in FODMAPs. Wheat contains moderate amounts of FODMAP carbohydrates, but many other foods -- notably, many common fruits and vegetables like apples, peaches, asparagus and broccoli -- contain higher amounts. The study sought to determine whether reducing FODMAP foods had any effect on specific symptoms -- gastrointestinal issues and fatigue -- in people with irritable bowel syndrome but not celiac disease who reported improvement a gluten-free diet. The 37 participants followed a gluten-free low-FODMAP diet for two weeks, after which they received one weeks worth of supplements containing either high amounts (16 grams per day) of nearly pure wheat gluten, low amounts (2 grams per day) of nearly pure wheat gluten, or 16 grams per day of whey protein (milk derivative) isolate. After a week on each supplement, the subjects would revert to the original diet for at least two weeks -- until any symptoms resolved -- before switching to another supplement. All 37 subjects tried all three supplements, although two patients each stopped taking one of their supplements early because of intolerable symptoms (one was in the high-gluten arm at the time, while the other was in the whey protein arm). Almost two-thirds of the subjects then participated in a second, shorter phase of the trial featuring the same three supplements and an even more restrictive background diet that also eliminated dairy. Results Indicated Few Changes with Pure Gluten Challenge The study found most of the subjects IBS-type symptoms -- abdominal pain, bloating, satisfaction with stool consistency, flatulence, nausea and fatigue) -- improved after two weeks on the gluten-free, low-FODMAP diet. Once the participants started taking the supplements, their overall symptoms and pain increased ... regardless of whether they were taking the high-gluten, low-gluten or whey protein supplement. Only six people -- 16% of the total -- reported a significant increase in overall abdominal symptoms in the high-gluten arm of the trial, and only one of these subjects reported more symptoms overall in the low-gluten arm of the trial. Three people reported higher symptoms in the placebo arm of the trial, while one person reported more symptoms in all arms of the trial. A dose effect of gluten was not observed and gluten specificity of symptomatic responses was observed in only three subjects (8% of the total cohort), the authors wrote. Eleven participants (30%) had a positive response in overall symptom severity in the placebo arm, eight of whom also reacted in the low-gluten arm. Only one of these eight responded to the high-gluten arm. Seven subjects (19% of the total cohort) had whey-specific symptomatic responses. In the shorter second phase of the trial, the researchers attempted to reproduce symptoms in people who had responded to gluten, but they failed to do so. There also were no significant differences across the treatment periods in several medical tests performed on the subjects, including celiac blood tests. The study wasnt perfect: the researchers noted several limitations of their trial. First, they found a strong anticipatory symptomatic response in their study subjects -- in other words, the participants were expecting to endure symptoms, and therefore could have psyched themselves into them. In addition, the trial itself required participants to comply with fairly rigorous rules for their diets, along with frequent medical testing, stool collection and daily questionnaires. This also could have contributed to symptoms across the three arms of the trial, the authors said. Nonetheless, the trial showed that most people didnt experience symptoms when exposed to 16 grams of gluten per day (the equivalent of about five slices of wheat bread). So What Does All This Mean? The researchers concluded that the people who completed this exhaustive trial showed no evidence of specific or dose-dependent effects of gluten. They acknowledged that the study design itself -- and the stresses involved in participating -- may have induced symptoms in participants. The researchers also noted that a study they performed prior to this one did show evidence of a gluten-induced effect in people with IBS. But do the results of this study mean theres no such thing as non-celiac gluten sensitivity? Hardly. Check back tomorrow, when Ill have more from Dr. Fasano (plus some thoughts of my own). Keep up with the latest in the celiac disease/gluten sensitivity world -- sign up for my newsletter, connect with me on Facebook and Google+, or follow me on Twitter - @AboutGlutenFree. Photo © Getty Images/Jupiterimages Comments (3) See All Posts Share Prev Next Leave a Comment Comments September 9, 2013 at 5:16 pm(1) Urooj says: I have IBS, and gluten-free food is usually recommended for the low FODMAP diet (as wheat is high in insoluble fibre, and is a high FODMAP item). It’s not to say that we cannot have any at all (gluten/wheat that is), but that we should avoid it or eat as little as possible. However, isn’t NCGS -not- the same as IBS? And how about people who not have only gastrointestinal symptoms but neurological, skin, etc. related too after ingesting gluten – after a little bit or a lot (as I do believe there is a spectrum)? IBS is only seen as a GI disorder i.e. that it only affects your bowels.
Posted on: Mon, 10 Mar 2014 14:07:36 +0000
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