Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity

[Skycloud]

Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity

Gry I. Skodje et al

Gastroentorology February 2018Volume 154, Issue 3, Pages 529–539.e2

http://www.gastrojournal.org/article/S0016-5085(17)36302-3/fulltext

ABSTRACT
Background & Aims
Non-celiac gluten sensitivity is characterized by symptom improvement after gluten withdrawal in absence of celiac disease. The mechanisms of non-celiac gluten sensitivity are unclear, and there are no biomarkers for this disorder. Foods with gluten often contain fructans, a type of fermentable oligo-, di-, monosaccharides and polyols. We aimed to investigate the effect of gluten and fructans separately in individuals with self-reported gluten sensitivity.

Methods
We performed a double-blind crossover challenge of 59 individuals on a self-instituted gluten-free diet, for whom celiac disease had been excluded. The study was performed at Oslo University Hospital in Norway from October 2014 through May 2016. Participants were randomly assigned to groups placed on diets containing gluten (5.7 g), fructans (2.1 g), or placebo, concealed in muesli bars, for 7 days. Following a minimum 7-day washout period (until the symptoms induced by the previous challenge were resolved), participants crossed over into a different group, until they completed all 3 challenges (gluten, fructan, and placebo). Symptoms were measured by Gastrointestinal Symptom Rating Scale Irritable Bowel Syndrome (GSRS-IBS) version. A linear mixed model for analysis was used.

Results
Overall GSRS-IBS scores differed significantly during gluten, fructan, and placebo challenges; mean values were 33.1 ± 13.3, 38.6 ± 12.3, and 34.3 ± 13.9, respectively (P = .04). Mean scores for GSRS-IBS bloating were 9.3 ± 3.5, 11.6 ± 3.5, and 10.1 ± 3.7, respectively, during the gluten, fructan, and placebo challenges (P = .004). The overall GSRS-IBS score for participants consuming fructans was significantly higher than for participants consuming gluten (P = .049), as was the GSRS bloating score (P = .003). Thirteen participants had the highest overall GSRS-IBS score after consuming gluten, 24 had the highest score after consuming fructan, and 22 had the highest score after consuming placebo. There was no difference in GSRS-IBS scores between gluten and placebo groups.

Conclusions
In a randomized, double-blind, placebo-controlled crossover study of individuals with self-reported non-celiac gluten sensitivity, we found fructans to induce symptoms, measured by the GSRS-IBS. Clinicaltrials.gov no: NCT02464150.

 

[Skycloud]

Was alerted to this by Jen Brea tweet. My excuses for not trying fodmap, or at least fructan free, diet are dwindling. Would appreciate feedback on the paper

 

[hixxy]

Wouldn't people with supposed non-celiac gluten sensitivity still be symptomatic after avoiding gluten if it was fructans? There are a lot of other foods containing fructans that these people don't necessarily avoid.

 

[alicec]

There is a related thread discussing a report on this study, rather than the actual study.

I discussed what fructans actually are in that thread that noted that

Articles like this one and by various nutritionists expanding on FODMAP diets seem to miss the essential point of what these substances actually do.

The original paper also misses the point.

In any case, the study itself is not terribly impressive. In the summary they state

There was a significant difference in mean overall GSRS-IBS across gluten, fructan, and placebo challenges; mean (SD) scores were 33.1 (13.3), 38.6 (12.3), and 34.3 (13.9), respectively (P = .04, Figure 2)

In the results section, they go on to say,

Corrected for multiple comparisons, the overall GSRS-IBS was borderline significant for fructan vs gluten (P < .049). No significant differences were found for fructan vs placebo (P = .19) and gluten vs placebo (P = .99).

That's pretty dishonest in my book since many people only read the summary to get the gist of the study. The authors are deliberately trying to make their results look better than they actually are (not that the uncorrected results are outstanding either) because they are so marginal.

The best they can scrape up is a borderline difference between fructan and gluten response. Note there is no difference between fructan and placebo response so really does this mean anything at all? If it does mean anything, they are saying that, for the overall group, there was a slightly increased response to fructans.

They go on to look at individual response within the group and report

Thirteen participants had the highest overall GSRS-IBS score after consuming gluten, 24 had the highest score after consuming fructan, and 22 had the highest score after consuming placebo.

The group size was 59, so about 1/4 participants had the highest response to placebo, just slightly more had the highest response to fructans and about 1/5 had the highest response to gluten.

Not really anything to get terribly excited about and we are still none the wiser about the cause of non-coeliac gluten sensitivity.

 

[Skycloud]

Thank you @alicec - a big help (so foggy!)