http://www.ncbi.nlm.nih.gov/pubmed/21224837

Am J Gastroenterol. 2011 Jan 11. [Epub ahead of print] Gluten Causes Gastrointestinal Symptoms in Subjects Without Celiac Disease: A Double-Blind Randomized Placebo-Controlled Trial. Biesiekierski JR, Newnham ED, Irving PM, Barrett JS, Haines M, Doecke JD, Shepherd SJ, Muir JG, Gibson PR.

Monash University Department of Medicine and Gastroenterology, Box Hill Hospital, Box Hill, Victoria, Australia. Abstract OBJECTIVES: Despite increased prescription of a gluten-free diet for gastrointestinal symptoms in individuals who do not have celiac disease, there is minimal evidence that suggests that gluten is a trigger. The aims of this study were to determine whether gluten ingestion can induce symptoms in non-celiac individuals and to examine the mechanism.

METHODS: A double-blind, randomized, placebo-controlled rechallenge trial was undertaken in patients with irritable bowel syndrome in whom celiac disease was excluded and who were symptomatically controlled on a gluten-free diet. Participants received either gluten or placebo in the form of two bread slices plus one muffin per day with a gluten-free diet for up to 6 weeks. Symptoms were evaluated using a visual analog scale and markers of intestinal inflammation, injury, and immune activation were monitored.

RESULTS: A total of 34 patients (aged 29-59 years, 4 men) completed the study as per protocol. Overall, 56% had human leukocyte antigen (HLA)-DQ2 and/or HLA-DQ8. Adherence to diet and supplements was very high. Of 19 patients (68%) in the gluten group, 13 reported that symptoms were not adequately controlled compared with 6 of 15 (40%) on placebo (P=0.0001; generalized estimating equation). On a visual analog scale, patients were significantly worse with gluten within 1 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. There were no significant changes in fecal lactoferrin, levels of celiac antibodies, highly sensitive C-reactive protein, or intestinal permeability. There were no differences in any end point in individuals with or without DQ2/DQ8.

CONCLUSIONS: "Non-celiac gluten intolerance" may exist, but no clues to the mechanism were elucidated.Am J Gastroenterol advance online publication, 11 January 2011; doi:10.1038/ajg.2010.487.

PMID: 21224837 [PubMed - as supplied by publisher]

Thanks for linking my article on this, Stephen.

PubMed isn't great for doing searches unless you know exactly what you're looking for, and regular Google is cluttered with so much unhelpful pontificating on gluten that it's hard to get good answers.

Google Scholar is really the way to go for this type of research. Coincidentally I just wrote a post about how to find free scientific studies so that might help.

If you just want a shortcut, here's a pre-built search query for gluten studies in non-celiac individuals on Scholar (7,270 results).

Good timing. Stephan just published a blog post on it today.

Eating Wheat Causes Symptoms in Some People Who Don't Have Celiac Disease

Maelán Fontes Villalba at Lund University recently forwarded me an interesting new paper in the American Journal of Gastroenterology. Dr. Jessica R. Biesiekierski and colleagues recruited 34 IBS patients who did not have celiac disease, but who felt they had benefited from going gluten-free in their daily lives*. All patients continued on their pre-study gluten-free diet, however, half were given two slices of wheat bread and one wheat muffin per day, and the other half were given the same foods made from gluten-free ingredients.

During the six weeks of the intervention, patients receiving the gluten-free food fared considerably better on nearly every symptom of IBS measured. The most striking difference was in tiredness-- the gluten-free group was much less tired on average than the gluten group. Interestingly, they found that a negative reaction to wheat was not necessarily accompanied by the presence of anti-gluten antibodies in the blood, which is a test often used to diagnose gluten sensitivity.

A previous study in 1981 showed that feeding volunteers a large dose of gluten every day for 6 weeks caused adverse gastrointestinal effects, including inflammatory changes, in relatives of people with celiac disease, who did not themselves have celiac (3). Together, these are the most solid evidence that gluten can be damaging in people without celiac disease, a topic that has not received much interest in the biomedical research community.

FWIW, I think Stephan's blog is better than any peer-reviewed journal... but anyway, the article linked in the quote above should get you started.

Some more to add to the growing list.

Antinutritive effects of wheat-germ agglutinin

Insulin-like activity of concanavalin A and wheat germ agglutinin

Plant lectins as carriers for oral drugs

Gliadin, zonulin and gut permeability

Effect of gluten exorphins A5 and B5 on the postprandial plasma insulin level

The gluten connection: the association between schizophrenia and celiac disease.

Anotehr large list of scholarly journal articles here: http://www.greenmedinfo.com/search/node/gluten