Nutritional Pearls: Non-Celiac Gluten Sensitivity

Sara is a 40-year-old female who suffers from irritable bowel syndrome.  She had previously tested negative on workup for Celiac Disease but had read a few years back that a gluten free diet may help her symptoms.  She switched to a gluten-free diet at the time with a report that her symptoms improved since.

She believes that she has non-celiac gluten sensitivity which is causing her irritable bowel syndrome, but has seen a news report that a gluten-free diet may not be responsible for the improvements in her symptoms. Should she continue with her gluten-free diet? If not, what diet would you suggest for her?  

What diet would you recommend for Sara?

What is the correct answer?
(Answer and discussion on next page)

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Answer: Non-celiac gluten sensitivity doesn’t appear to exist.

There's been a fair amount of coverage in the health news on recent research into non-celiac gluten sensitivity (NCGS). A study that appeared to confirm the existence of NCGS was later refuted by another study, performed by the same team. Their conclusion was that, despite earlier research, they could find no evidence that non-celiac gluten sensitivity exists. Note: Today's research review is not of the study performed by that team. It does, however, come to the same conclusion: Non-celiac gluten sensitivity does not appear to exist when tested for under controlled conditions.

Research

In a very well designed trial, a team in Australia performed 2 studies: first, a double-blinded, placebo-controlled, crossover dietary trial, then an additional, briefer trial between 8 and 17 months later.¹

Thirty-seven men and women with clinically verified irritable bowel syndrome (IBS) who reported that their symptoms improved on a gluten-free diet (GFD) were recruited from area dietitians, gastroenterologists, or advertisements. They were verified to be free of celiac disease through testing for the genetic marker of the disease or via upper endoscopy and biopsy of small intestine.

The researchers educated the participants about FODMAPs—Fermentable, Oligo-, Di-, Monosaccharides, and Polyols, which are short-chain carbohydrates that are poorly absorbed in the gut—that are known triggers of gut symptoms similar to those experienced by people with celiac disease.

After an initial 1-week period where the participants continued their usual gluten-free diet, all of the subjects were supplied with a low-FODMAP diet for 2 weeks. Each participant was then randomly assigned to receive 1 of 3 supplements for a week: a high-gluten supplement, a low-gluten supplement, or a placebo—all of which contained the same amount of proteins.

After 1 week on 1 type of supplement, the subject switched back to the basic FODMAP diet for 2 weeks. This was repeated 3 times until all of the participants had spent 1 week on all 3 of the diets.

The subjects kept careful daily records of their levels of fatigue and any intestinal trouble they might encountered. They were also subjected to regular blood tests for markers of anti-gliadin antibodies and they supplied fecal samples for testing as well.
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Second Study

For the second study—the rechallenge trial—22 of the original participants repeated the study with the test diets lasting only 3 days each, for a 1-week period between each 3-day test. Again, they kept careful fatigue and symptom diaries and followed a gluten-free FODMAP diet other than the supplements provided by the researchers. Their blood and stool were not tested. For this study, the researchers took the additional step of restricting dairy products and other food additives suspected of triggering similar symptoms.

If the participants truly were sensitive to wheat gluten in a manner depending on the dose (as is the contention of those supporting the existence of NCGS), one would expect that they would experience more intestinal symptoms when they were receiving the high-gluten supplement, somewhat fewer symptoms with the low-gluten supplement, and no additional symptoms on the placebo.

They did not.

The Results

In the first study, all of the participants experienced improvement in their symptoms in the second week of the initial FODMAP diet period. Then, regardless of which diet they were on, their overall symptoms and pain worsened during the third week of each diet. Bloating and tiredness, the researchers reported, actually worsened only during the low-gluten and placebo diet periods.

The rechallenge trial fared about the same: Symptoms worsened about the same amount during the 3-day diet periods regardless of what supplement the participants received. One would also expect that the same participants would experience similar symptoms each time they were presented with 1 of the levels of supplementation, but they did not.

The researchers were unable to correlate the participant's change in symptoms with any other variable combination they considered—whether age, body mass index, gene marker, or length on a gluten-free diet prior to the start of the study.

What’s the “Take Home”?

The researchers concluded that there was “no evidence of specific or dose-dependent effects of gluten on patients with NCGS placed on a low FODMAP diet.” Consider recommending that your IBS patients try a low FODMAP diet. Here are resources from the original researchers into FODMAPs: www.med.monash.edu/cecs/gastro/fodmap/ 

Reference:

1. Biesiekierski J, Peters S, Newnham E, et al. No effects of gluten in patients with self-reported non-celiac gluten sensitivity after dietary reduction of fermentable, poorly absorbed, short-chain carbohydrates. Gastroenterology. 2013;145(2):320-328.