Which Diet is Best for Irritable Bowel Syndrome? A Randomized Trial

A Rej et al. Clin Gastroenterol Hepatol 2022; 20: 2876-2887. Open Access! Efficacy and Acceptability of Dietary Therapies in Non-Constipated Irritable Bowel Syndrome: A Randomized Trial of Traditional Dietary Advice, the Low FODMAP Diet, and the Gluten-Free Diet

Methods: In patients (n=99) with Rome IV–defined non-constipated IBS, outcomes after randomization to one of three diets were compared. The “traditional dietary advice” group: “Its principles include adopting healthy, sensible eating patterns such as having regular meals, never eating too little/too much, maintaining adequate hydration, and reducing the intake of (1) alcohol/caffeine/fizzy drinks, (2) fatty/spicy/processed foods, (3) fresh fruit to a maximum of 3 per day, (4) fiber and other commonly consumed gas-producing foods (eg, beans, bread, sweeteners, etc), and (5) addressing any perceived food intolerances (eg, dairy).” (Link: National Institute for Health and Care Excellence advice on IBS mgt). The Gluten-Free diet allowed for cross-contamination. All patients had specialist dietary counseling.

Key findings:

  • All three diets resulted in improvement. The primary end point of ≥50-point reduction in IBS-SSS was met by 42% (n = 14/33) undertaking TDA, 55% (n = 18/33) for LFD, and 58% (n = 19/33) for GFD (P = .43)
  • Alterations in stool dysbiosis index were similar across the diets, with 22%–29% showing reduced dysbiosis
  • “The pragmatic study design, whereby the responsibility was left on patients to undertake the diets following appropriate education, means our findings can be generalized”

My take: All three diet approaches would be appropriate to reduce IBS symptoms, thought the TDA is the easiest for patients.

Related blog posts:

Gluten-Free Diet –Role in IBS?

MI Pinto-Sanchez et al. Clin Gastroenterol Hepatol 2021; 19: 2343-2352. Open Access: Gluten-Free Diet Reduces Symptoms, Particularly Diarrhea, in Patients With Irritable Bowel Syndrome and Antigliadin IgG

In this prospective study of 50 patients with IBS (ROME III, all subtypes), with and without serologic reactivity to gluten (antigliadin IgG and IgA), and 25 healthy subjects (controls) were studied before and after 4 weeks of a GFD. Celiac disease (CD) was ruled out in patients and controls by negative tissue transglutaminase (tTG) IgA antibody and deamidated gliadin IgA or IgG antibodies and by the absence of mucosal atrophy in a duodenal biopsy specimen (Marsh 0 or 1). At least 4 and 2 biopsy specimens were obtained from the second and the first part of the duodenum, respectively.

Key findings:

  • Compared with baseline, IBS symptoms improved in 18 of 24 patients (75%) with antigliadin IgG and IgA and in 8 of 21 patients (38%) without the antibodies
(A) Improvement in IBS symptoms (>4.5 points in the total Birmingham score) in antigliadin antibody (AGA)+ and AGA patients after GFD. (B) Change in IBS symptoms after a gluten-free diet (GFD) compared with baseline in AGA+ and AGA patients.

The associated editorial (A Rej et al. Open Access: Personalizing Dietary Therapies For Irritable Bowel Syndrome: What Is Gluten’s Role?) provides some useful points:

  • “A key trigger for symptom generation in IBS is diet, with more than 80% reporting food-related symptoms…It seems that wheat is a key component for symptom generation in IBS, as demonstrated by a study in 920 patients by Carroccio et al,8 which identified wheat sensitivity in 30% of patients”
  • The authors note that the Pinto-Sanchez population had a higher-than-expected rate of AGA positivity of 50% when previous studies have found rates of 7-18%.

My take: This prospective study indicates that a GFD is associated with clinical improvement in a significant number of individuals with IBS (with and without antigliadin antibodies) who did not report any gluten sensitivity or were not on a gluten-restricted diet before study entry. Based on a number of other studies, however, it seems that a low FODMAPs diet is likely to have a higher efficacy for patients with IBS.

Related blog posts:

Persistent Villous Atrophy in Celiac Disease Despite a Gluten-Free Diet

A recent study (F Fernandez-Banares et al. Am J Gastroenterol 2021; 116: 1036-1043. Persistent Villous Atrophy in De Novo Adult Patients With Celiac Disease and Strict Control of Gluten-Free Diet Adherence: A Multicenter Prospective Study (CADER Study) shows that there is a high likelihood of persistent villous atrophy among adults with celiac disease (CD) despite adherence with a gluten-free diet (GFD). Thanks to Ben Gold for showing me this paper.

Key findings:

  • Among 76 patients (median age 36.5 years) who were prospectively followed for 2 years, persistent villous atrophy was observed in 40 (53%). In this group, 72.5% were asymptomatic (based on Likert scales) and 75% had negative serology
  • Detectable fecal gluten immunogenic peptides (f-GIPs) were present in at least one sample in 69% of patients. (Two samples obtained at f/u visits which were ~every 6 months during study)
  • Excellent or good adherence to GFD was demonstrated in 68.4% of patients based on dietetic evaluations. Only 6 (8%) were clearly nonadherent
  • “There were no significant differences in the rate of clinical and serological remission between patients with villous atrophy and those with mucosal recovery”
  • The authors did not find potentially modifiable predictive factors


  • The authors note that serology is “not useful for monitoring patients on a GFD.” Anti-TTG2 and EMA, in a recent meta-analysis, had a pooled sensitivity of around 50%.
  • “Adults are significantly less likely than children to normalize their duodenal histology.”


  • The associated editorial by Rej et al (pg 946-948) outline a personalized approach for dealing with persistent villous atrophy:
    • In those with persistent symptoms/positive GIPs/elevated serology/micronutrient deficiency, the first step is careful dietetic assessment. After this, endoscopy could be considered to confirm presence or absence of mucosal healing.
    • In those with no symptoms and no abnormalities, use of monitoring endoscopy needs to be weighed against the costs as well as potential complications.
    • Other points in the editorial: 1. GIPs have poor concordance with mucosal healing and 2. causes of poor mucosal healing include the following: natural slow healing process, super sensitive to gluten, ongoing gluten exposure, and refractory celiac disease.

My take: This study shows that there is ongoing gluten exposure in the majority of patients even in those with excellent or good adherence to a GFD; in addition, it shows that clinical/serological markers are NOT effective in predicting mucosal healing in adults. Nevertheless, it is not clear that followup endoscopy is beneficial.

Related blog posts:

Forbes (7/1/21): 99.5% Of People Killed By Covid In Last 6 Months Were Unvaccinated, Data Suggests

Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition

Real-World = Partially-Treated Celiac Disease

A recent prospective observational study reinforces the idea that most people with celiac disease are unable to accomplish a strict gluten-free diet (GFD): JP Stefanolo et al. Clin Gastroenterol Hepatol 2021; 19: 484-491. Real-World Gluten Exposure in Patients With Celiac Disease on Gluten-Free Diets, Determined From Gliadin Immunogenic Peptides in Urine and Fecal Samples

The investigators enrolled 53 adults with celiac disease (CD) for at least two years and followed symptoms as well as stool/urine testing for gluten immunogenic peptide (GIP). “GIP in stool can detect gluten consumption of more than 40 mg/d and the urine tests are positive from 40 and 500 mg/d of gluten.”

Key findings:

  • Over the 4-week study period, weekend samples (urine) identified 70% of patients excreted GIP at least once, compared with 62% during weekdays (stool).
  • Patients had a median of 3 exposures during the 4 weeks.
  • Also, the authors noted increases in GIP excretion towards the end of the study. “This suggests a potential Hawthorne effect that could be explained by a decrease in hypervigilance that often is seen in a context of research studies.”

The authors note that GIP “excretions of greater than 2 mcg/g in stool or greater than 12 ng/mL in urine can induce mucosal damage in almost 100% of patients.”

My take: This study adds to the body of literature emphasizing the high rate of inadvertent gluten exposure.

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Before and After at Lake Michigan shoreline (1 month apart in Evanston, IL)

Early January -Evanston, IL
Early February -Evanston, IL

Gluten-Free Diet Can Be Unhealthy

In some patients with celiac disease, institution of a gluten-free diet may be detrimental without good dietary counseling as a highly-processed diet can increase the risk of adverse cardiovascular events.

A recent study (J Runde et al. JPGN 2020; 71: 533-535. A Narrow Window: Booming Gluten-free Market and Fostering Healthy Dietary Habits in Children With Celiac Disease) assessed dietary patterns of children with celiac disease and indicates that early counseling is crucial.

In total dietary surveys were completed for 100 children with celiac disease. Key findings:

  • 77% consumed processed gluten-free (GF) foods multiple times per day
  • 20% ate exclusively processed GF foods
  • The main reasons for processed GF foods were convenience and taste
  • Patients and families interest in dietary counseling diminished with time. In children <1 year from diagnosis, 35% were interested in dietary feedback, compared to 18% 2-3 years after diagnosis, 15% 4-6 years after diagnosis, and 11% at 7+ years from diagnosis

The authors speculate that highly-processed foods are leading to obesity which is increasingly reported in pediatric celiac disease.

My take:

  • The greatest opportunity for dietary counseling is at the time of the diagnosis.
  • Children with celiac disease commonly consume an unhealthy diet and are at risk for the same types of outcomes as children without celiac disease who also frequently consume an unhealthy diet

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It looks like the COVID-19 epidemic is going to get worse -while there is more testing, there is also a trend of more hospitalizations that is not likely explained by more testing.

Is A Gluten-Free Diet Possible? DOGGIE BAG Study. And Face Mask Use in U.S.

A recent study (JA Silvester et al. Gastroenterol 2020; 158: 1497-99)  examined the diet of 18 participants with celiac disease who endorsed no intentional gluten ingestion.


There are two ways you could interpret the name of the new Doggie Bag study, which investigates how much gluten people with celiac disease are getting in their diets. And each would be correct.

Participants in the study provided portions of all the food they ate over 10 days – what you could think of as the doggie bag you bring home from a restaurant. They also provided stool samples, which might bring to mind the bags dog owners use to clean up after their pets.

Either way, the name reflects the commitment made by 18 celiac disease patients on the gluten-free diet who took part in the 10-day review of all the gluten going in and coming out of their bodies. Urine samples were also collected.

Celiac disease researchers tested all the samples for the presence of gluten immunogenic peptides (GIP) and concluded that 66 percent of the patients trying to follow a strict gluten-free diet showed evidence, by one measure or another, of being exposed to gluten. The amount of gluten varied from .23 milligrams (mg) to more that 40 mg with each exposure. Up to 10 mg of gluten per day is generally considered a safe level of gluten consumption for most people with celiac disease, according to the University of Chicago Celiac Disease Center.

Key findings:

  • 25 of 313 (8%) of food samples from 9 participants had detectable gluten with a median of 11 parts per million
  • 12 of 18 with good or excellent GFD adherence based on standardized self-report were exposed to gluten within the 10-day study period
  • Among the 12 with gluten detected in their diet, 5 (42%) had abnormal TTG IgA antibody levels and 8 (66%) had Marsh 3A histology; in the 6 with no gluten detected, 2 (33%) had abnormal TTG IgA antibody levels and 2 (33%) had Marsh 3A histology

My take: For many patients with celiac disease, a “GFD may be more aspirational than achievable, even by highly committed and knowledgeable individuals.”

Related blog posts:


From YouGov survey: The states that are more and less likely to adopt face masks

  • Methodology: The survey is based on the interviews of 89,347 US adults aged 18 and over between March 26-April 29, 2020. All interviews were conducted online and the results have been weighed to be nationally representative.
  • During the course of April, the share of Americans who wore face masks while out in public surged from 17 percent at the start of the month to 63 percent by month’s end
  • A state-by-state analysis reveals some states are significantly more likely to adopt face masks than others. Georgia was ahead of nationwide average during study period (45% compared to 43% nationwide)


Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition

Gluten-Free –No Evidence It is Helpful for Healthy Individuals

A recent study (ID Croall, et al. Gastroenterol 2019; 157: 881-3) provides additional data indicating that a gluten-free diet does not confer health benefits to healthy individuals.

A double-blind randomized placebo 2-week trial with 30 healthy adults divided subjects into two groups –some received flour sachets to consume with organic gluten (14 g) and some received a gluten-free blend (rice, potato, tapioca, maize, buckwheat flour). Both groups were instructed to take their flour sachets twice a day along with a gluten-free diet (GFD).

Key finding: The group receiving gluten did not experience any increase in gastrointestinal symptoms or fatigue compared to the placebo group.

My take: While this study lasted only 2 weeks and had a small sample size, nevertheless, it adds to the literature indicating that a GFD is unlikely to be beneficial in otherwise healthy individuals. Those who stick with a GFD should seek the help of a well-qualified dietician.

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Portland, OR. Portland aerial trams –between the city’s South Waterfront district and the main Oregon Health & Science University (OHSU) .

Economic Costs of Gluten Free Diet

A recent study (AR Lee et al. Nutrients; 2019, 11, 399). Open access: Persistent Economic Burden of the Gluten Free Diet) quantifies the additional costs of a gluten free diet (GFD) in the U.S. Thanks to Kipp Ellsworth for this reference.

The authors conducted a “market basket” study to establish the cost of a GFD. “A market basket is a group of products that are purchased by consumers …for this study, the market basket was food that would necessitate a GF substitute, including staple foods, snack foods, and commonly used ready-made or convenience meals.”

Key findings:

  • GF products were more expensive, overall the increase was 183%.  This is an improvement from a 2006 study which found the increase overall at 240% (adjusted for inflation).
  • Mass-market products were 139%  more expensive than wheat-based versions


  • Cost is identified as a frequent reason for nonadherence with diet, cited by 33% in one study
  • Overall, the burden of GFD is more frequently related to the restrictive nature of the diet which leads to a negative impact on quality of life. According to the authors, in one study (Am J Gastroenterol 2014; 109: 1304-11), treatment burden for celiac was ranked higher than for diabetes hypertension, and congestive heart failure

My take: This study shows the significant economic burden of a GFD.  In Italy, the  “government offers celiac patients vouchers to buy gluten-free food — up to 140 euros per month.” (NPR: Italy, Land of Pizza and Pasta)

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Evidence-Based IBS Treatment Recommendations from ACG

A recent  American College of Gastroenterology Task Force conducted a systematic review (AC Ford et al. The American Journal of Gastroenterology 2018;113:1–18 ) to update management recommendations for irritable bowel syndrome -Link:

American College of Gastroenterology Monograph on Management of Irritable Bowel Syndrome

The highlights of this report are summarized at Gastroenterology & Hepatoloy: Highlights of the Updated Evidence-Based IBS Treatment Monograph

A few excerpts:

“There have been numerous studies performed on the roles of diet and dietary manipulation in IBS. Three fairly firm conclusions were made following the review of these studies: (1) the low–fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet seems to be effective for overall IBS symptom improvement; (2) a gluten-free diet is not effective for symptom improvement; and (3) conducting tests to detect various types of allergies or intolerances in order to base a diet on those results does not appear to be effective. Of these 3 conclusions, the most impressive data that came out of the research was the evidence for the low-FODMAP diet. Not only were there more studies on this diet, but the results were fairly consistent and favorable, at least for the short-term management of IBS.”

” We did not find evidence supporting the idea that prebiotics and synbiotics were effective in IBS management… In ­contrast, studies demonstrated that probiotics did improve global gastrointestinal symptoms, as well as the individual symptoms of bloating and flatulence in patients with IBS. However, determining which probiotic is best was difficult”

“Three prosecretory agents are available: linaclotide (Linzess, Allergan/Ironwood Pharmaceuticals), lubiprostone (Amitiza, Takeda), and plecanatide (Trulance, Synergy Pharmaceuticals), with plecanatide being the most recently approved agent. All 3 of these agents had convincing data to support their use in patients with constipation-predominant IBS

My take: In IBS patients, if dietary therapy is recommended, current evidence favors a low FODMAP diet rather than a gluten-free diet.

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near Banff

Image above -Parker Ridge Trail

Is it Helpful to Check Celiac Serology Titers After 3 Months of a Gluten Free Diet?

A recent prospective study (D Petroff et al. Clin Gastroenterol Hepatol 2018; 16: 1442-49) with 345 pediatric patients with biopsy-proven celiac disease (CD) examined serologic response to a gluten-free diet (GFD) between 2012-2015.

Key findings:

  • Mean TTG IgA concentration decreased 14-fold after 3 months of a GFD.  The study assay used kits from EUROIMMUN.
  • TTG IgA remained above 1-fold ULN in 83.8% and above 10-fold ULN in 26.6%.
  • Deamidated gliadin IgA (DGL IgA) decreased in the vast majority but did not distinguish response of GFD from random fluctuations.
  • The authors note that symptoms improved in most on GFD, but short-term response could reflect “regression to the mean…for a considerable share” as symptoms improved in the non-GFD group as well.

In their discussion, the authors reference a large study (n=487) which showed mean normalization of TTG IgA of ~400 days; longer times were noted in those with type 1 diabetes and higher baseline values.

My take: This study, while showing that TTG IgA levels improve after 3 months of a GFD, helps solidify my opinion that in those who are improving, followup serology could be obtained later.  My practice is to have followup serology after 6 months of a GFD in the majority of patients.

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Lake Moraine, Banff