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Healthcare professional Resource for Gluten Related Disorders.

Dr. Schär Institute

Treatment of Irritable bowel syndrome

Research shows that patients often seek advice on dietary intervention in order to help their IBS symptoms [1]. Understandably patients want to know which foods to avoid and which are safe to eat.
For many patients a transition to a simple healthy eating pattern may be sufficient to reduce symptoms considerably.

Over the last few years considerable research has been focused on looking for more specific and effective dietary solutions for IBS, in particular the Low FODMAP Diet and the gluten free diet. Indeed, the Low FODMAP Diet is discussed for IBS in the NICE Guidance [2], NASPGHAN, Academy of Nutrition and Dietetics and in the British Dietetic Association IBS Guidance [3].

The low FODMAP diet

The Low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet was developed by a team from Monash University in Melbourne, Australia. The mechanisms by which these fermentable carbohydrates provoke gut symptoms are due to two underlying physiological processes: first, they are indigestible and subsequently fermented by the bacteria in the colon, which leads to gas production. The resulting gas can alter the gut environment and cause hypersensitivity in those who are susceptible to gut pain [4]. Secondly, there is an osmotic effect whereby fermentable carbohydrates increase water delivery to the colon leading to altered bowel habit [5].
There have been three randomized controlled trials published showing a clear benefit of using the Low FODMAP diet [4,6,7] and this data, along with three prospective uncontrolled trials [8-10] and two further retrospective trials [11,12], has led to fermentable carbohydrate restriction becoming an important consideration IBS treatment. Research indicates that patients using this diet report a marked improvement in symptoms, with up to 70% of patients reporting benefit [13].

First line dietary advice for IBS patients

The best way to manage IBS is to understand what may cause episodes of discomfort and then work to eliminate or minimize them. While medication, stress management and probiotics can help, the focus is on diet and eating habits. Both can have significant impact. Simple changes in your diet can offer relief and reduce future flare-ups.
  • Establish regular eating habits. Eating at regular times helps regulate your bowels.
  • Eat small, frequent meals instead of large ones. This will ease the amount of food moving through your intestinal tract.
  • Eat fiber-rich foods. Try whole fruits, vegetables (including beans) and whole grains including rolled oats, brown rice and whole-wheat bread. Make changes slowly. Fiber helps move food through your intestine, but it takes time for your body to adjust to eating more. Adding too much too quickly may result in gas, bloating and cramping.
  • Drink enough fluids. Fiber draws water from your body to move foods through your intestine. Without enough water and fluids you may become constipated.
  • Watch what you drink. Alcohol and caffeine can stimulate your intestines; this can cause diarrhea. Artificial sweeteners that contain sugar alcohols such as sorbitol, mannitol and xylitol may cause diarrhea too. Carbonated drinks can produce gas.
  • Identify problem foods and eating habits. Keeping a food diary during flare-ups can help you figure out what you may be eating that's causing a problem.
Source Academy of Nutrition and Dietetics

Where are FODMAPs found [15]?

Fermentable carbohydrate Type Relevant foods
Oligosaccharides Fructans, galacto-oligosaccharides Wheat, barley, rye, onion, leek, white part of spring onion, garlic, shallots, artichokes, beetroot, fennel, peas, chicory, pistachio, cashews, legumes, lentils and chickpeas
Disaccharides Lactose Milk, custard, ice cream and yogurt
Monosaccharides Free fructose (fructose in excess of glucose) Apples, pears, mangoes, cherries, watermelon, asparagus, sugar snap peas, honey, high-fructose corn syrup
Polyols Sorbitol, mannitol, maltitol, xylitol Apples, pears, apricots, cherries, nectarines, peaches, plums, watermelon, mushrooms, cauliflower, sugar free chewing gum/mints/sweets

A gluten-free diet for IBS

Research suggests that some patients with IBS (where celiac disease has been excluded) find symptom relief when following a gluten free diet [18-21]. The reasons behind this observation are hotly debated amongst experts in the field and may be related to the presence of non-celiac gluten sensitivity amongst a sub-group of IBS patients. It is also plausible that symptom improvement upon commencement of a gluten free diet is simply related to the concurrent reduction in the FODMAP content of the diet, namely a reduction in fructans found in wheat, barley and rye [22]. When considering the use of a gluten free diet for the management of IBS it is vital to ensure celiac disease has been excluded prior to the removal of wheat/gluten from the diet.


Research showing the benefits of probiotics in the treatment of IBS is conflicting and may be hampered by the fact that the human gut can be populated by any of 1000-1150 different bacterial species [23], and yet most probiotic supplements contain no more than a handful of species. Nevertheless, some probiotics have shown benefit and current NICE guidance [2] recommends that patients with IBS who choose to try probiotics should be advised to consume them for at least 4 weeks while  monitoring the effect on symptoms.

Pharmacological and alternative therapies

Pharmacological treatment options for the management of IBS should be based on symptom nature and severity, these may include antispasmodics, laxatives, anti-diarrheal agents, tri-clyclic antidepressants and selective serotonin reuptake inhibitors. Side effects from pharmacological therapies are common and symptom relief may be variable. Patients who do not respond to dietary or drug management of their symptoms may benefit from psychological interventions including hypnotherapy [2].
  1. Halpert A, Dalton CB, Palsson O, Morris C, Hu Y, Bangdiwala S, et al. What patients know about irritable bowel syndrome (IBS) and what they would like to know. National Survey on Patient Educational Needs in IBS and development and validation of the Patient Educational Needs Questionnaire (PEQ). Am J Gastroenterol. 2007;102(9):1972-82.
  2. National Institute for Health and Care Excellence. Irritable bowel syndrome in adults: diagnosis and management of irritable bowel syndrome in primary care. London: NICE; 2015.
  3. McKenzie YA, Alder A, Anderson W, Wills A, Goddard L, Gulia P, et al. British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults. J Hum Nutr Diet. 2012;25(3):260-74
  4. Ong DK MS, Barrett JS, Shepherd SJ, Irving PM, Biesiekierski JR, Smith S, Gibson PR, Muir JG,. Manipulation of dietary short chain carbohydrates alters the pattern of gas production and genesis of symptoms in irritable bowel syndrome. Journal of gastroenterology and hepatology. 2010;25(8):1366-73
  5. Murray K, Wilkinson-Smith V, Hoad C, Costigan C, Cox E, Lam C, et al. Differential effects of FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols) on small and large intestinal contents in healthy subjects shown by MRI. Am J Gastroenterol. 2014;109(1):110-9.
  6. Halmos EP, Power VA, Shepherd SJ, Gibson PR, Muir JG. A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology. 2014;146(1):67-75 e5.
  7. Staudacher HM, Lomer MC, Anderson JL, Barrett JS, Muir JG, Irving PM, et al. Fermentable carbohydrate restriction reduces luminal bifidobacteria and gastrointestinal symptoms in patients with irritable bowel syndrome. The Journal of nutrition. 2012;142(8):1510-8.
  8. de Roest RH, Dobbs BR, Chapman BA, Batman B, O'Brien LA, Leeper JA, et al. The low FODMAP diet improves gastrointestinal symptoms in patients with irritable bowel syndrome: a prospective study. Int J Clin Pract. 2013;67(9):895-903
  9. Mazzawi T, Hausken T, Gundersend D, El-Salhy M. Effects of dietary guidance on the symptoms, quality of life and habitual dietary intake of patients with irritiable bowel syndrome. Mol Med Rep. 2013;8:845-52.
  10. Wilder-Smith C, Materna A, Wermelinger C, Schuler J. Fructose and lactose intolerance and malabsoprtion testing: the relationship with symptoms in functional gastrointestinal disorders. Aliment Pharmacol Ther. 2013;37:1074-83.
  11. Gearry R, Irving PM, Barrett JS, Nathan DM, Shepherd SJ, Gibson PR. Reduction of dietary poorly absorbed short-chain carbohydrates (FODMAPs) improves abdominal symptoms in patients with inflammatory bowel disease - a pilot study. Journal of Crohns and Colitis. 2009;3(1):8-14
  12. Ostgaard H, Hausken T, Gundersend D, El-Salhy M. Diet and effects of diet management on quality of life and symptoms in patients with irritable bowel syndrome. Mol Med Rep. 2012;5:1382-90.
  13. Staudacher HM, Irving PM, Lomer MC, Whelan K. Mechanisms and efficacy of dietary FODMAP restriction in IBS. Nat Rev Gastroenterol Hepatol. 2014.
  14. Gibson PR, Shepherd SJ. Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. Journal of gastroenterology and hepatology. 2010;25(2):252-8.
  15. Shepherd SJ, Lomer MCE, Gibson PR, Rome Foundation Working Group: Short-chain carbohydrates and functional gastrointestinal disorders; Am J Gastroenterol; 2013, 108: 707-717
  16. Staudacher HM, Whelan K, Irving PM, Lomer MC. Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. J Hum Nutr Diet. 2011;24(5):487-95.
  17. Gibson PR, Barrett JS, Muir JG. Functional bowel symptoms and diet. Intern Med J. 2013;43(10):1067-74.
  18. Biesiekierski JR, Newnham ED, Irving PM, Barrett JS, Haines M, Doecke JD, et al. Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial. Am J Gastroenterol. 2011;106(3):508-14; quiz 15.
  19. Biesiekierski JR, Muir JG, Gibson PR. Is gluten a cause of gastrointestinal symptoms in people without celiac disease? Current allergy and asthma reports. 2013;13(6):631-8.
  20. Vazquez-Roque MI, Camilleri M, Smyrk T, Murray JA, Marietta E, O'Neill J, et al. A controlled trial of gluten-free diet in patients with irritable bowel syndrome-diarrhea: effects on bowel frequency and intestinal function. Gastroenterology. 2013;144(5):903-11 e3
  21. Shahbazkhani B, Sadeghi A, Malekzadeh R et al. Non-Celiac Gluten Sensitivity Has Narrowed the Spectrum of Irritable Bowel Syndrome: A Double-Blind Randomized Placebo-Controlled Trial. Nutrients. 2015 7(6): 4542-4554.
  22. Biesiekierski JR, Peters SL, Newnham ED. 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):320-8.
  23. Whelan K. Probiotics and prebiotics in the management of irritable bowel syndrome: a review of recent clinical trials and systematic reviews. Current opinion in clinical nutrition and metabolic care. 2011;14(6):581-7.

Further information on this topic

Studies 3

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Evidence for the Presence of Non-Celiac Gluten Sensitivity in Patients with Functional Gastrointestinal Symptoms: Results from a Multicenter Randomized Double-Blind Placebo-Controlled Gluten Challenge

Non-celiac gluten sensitivity (NCGS) is a syndrome characterised by intestinal and extra-intestinal symptoms related to the ingestion of gluten-containing food. Currently, available blood tests and histology do not help towards making the differential diagnosis, hence response to a gluten free diet in the absence of celiac disease (CD) or wheat allergy (WA) is the fundamental principal of diagnosis for NCGS. Unfortunately, the placebo effect, in addition to the presence of other active compounds within wheat, e.g amylase trypsin inhibitors (ATIs), and FODMAPs, may act as confounding factors when analysing the impact of gluten withdrawal amongst potential NCGS sufferers. A correct diagnosis is essential in order to avoid unnecessary dietary restriction, provide effective treatment options, and to reduce the need for drugs in order to manage the symptoms of patients reporting functional bowel disorders including IBS.

The aim of this study was to identify patients with NCGS from those reporting an improvement of gastrointestinal symptoms while following a gluten free diet (GFD), through a double-blind placebo-controlled gluten challenge with crossover. The study was carried out in 15 gastrointestinal out-patients centers in Italy. The study enrolled 140 adult patients routinely attending gastrointestinal outpatient clinics and meeting the Rome III criteria for functional gastrointestinal disorders. All were following a gluten-containing diet and had negative IgA anti-tTG, normal total IgA and negative IgE mediated WA. Amongst patients with high clinical suspicion of CD, a duodenal biopsy was also performed in order to identify any seronegative patients.

Phase one of the trial investigated subject response to a GFD. Symptoms and quality of life were evaluated using a series of 10cm visual analogue scales (VASs) and a SF36 questionnaire. Following this initial evaluation, patients were asked to follow a GFD for 3 weeks. Subjects were provided with detailed information and support regarding the diet by an expert nutritionist. At the end of phase 1, patients repeated the VASs and SF36 questionnaire. Only those patients reporting a significant improvement in well-being (VAS ≥ 3cm, n=101) were defined as ‘gluten responsive’ and were enrolled in to phase 2 of the study.

Gluten responsive patients were asked to maintain their strict GFD for phase 2 of the trial (placebo-controlled double-blind gluten challenge with crossover). Ninety eight subjects were enrolled in this phase of the study (3 subjects refused to proceed owing to fear of symptom relapse during challenge). Patients were randomised to receive either purified gluten capsules (5.6g/ day, equivalent to 80g of dried pasta) or the same volume of placebo capsules (rice starch) for 7 days. A 7 day washout period was scheduled between the cross-over periods, hence the total duration of phase 2 was 21 days (subjects followed a gluten free diet throughout). Subjects completed the VASs and SF36 questionnaire at the end of each 7 day period (gluten challenge, cross over and placebo). Overall, subjects reported a greater deterioration in well-being during the gluten challenge rather than during placebo administration (p=0.05). Twenty eight of the randomised patients were identified as being ‘positive’ to the DBPCC (ie with symptomatic relapse during gluten ingestion) and 69 were found to be ‘negative’ to the DBPCC (ie without any symptomatic reaction during gluten administration). No demographic, clinical or biochemical factors were found to be associated with the gluten challenge response. Among positive patients, there appeared to be no significant effect of capsule sequence. Notably, 14 of the 28 positive patients were also considered to be placebo responsive, indicating a significant ‘placebo effect’, as would be expected.

Overall, 14% of the 98 randomised ‘gluten responsive’ patients showed a symptomatic relapse during the blind placebo-controlled gluten challenge (without concurrent response to placebo) and accordingly can be defined as patients with NCGS. This finding confirms that gluten ingestion may induce gastrointestinal symptoms in a sub-set of patients with functional bowel disorders. This study is the first to assess the performance of the Salerno Experts’ diagnostic criteria1 for NCGS in a clinical setting. The large number of patients responsive to a GFD (75%) but negative to gluten challenge is interesting, a possible placebo affect is likely to account for some of this discrepancy, however many patients might also be sensitive to other unspecified wheat components, e.g ATIs or FODMAPs.

Elli L, Tomba C, Branchi R et al

Nutrients 2016; 8: 84; doi:10.3390/nu8020084
Elli, L; et al.;
2016 February

Diets that differ in their FODMAP content alter the colonic luminal microenvironment.


A low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) diet reduces symptoms of IBS, but reduction of potential prebiotic and fermentative effects might adversely affect the colonic microenvironment. The effects of a low FODMAP diet with a typical Australian diet on biomarkers of colonic health were compared in a single-blinded, randomised, cross-over trial.

Twenty-seven IBS and six healthy subjects were randomly allocated one of two 21-day provided diets, differing only in FODMAP content (mean (95% CI) low 3.05 (1.86 to 4.25) g/day vs Australian 23.7 (16.9 to 30.6) g/day), and then crossed over to the other diet with ≥21-day washout period. Faeces passed over a 5-day run-in on their habitual diet and from day 17 to day 21 of the interventional diets were pooled, and pH, short-chain fatty acid concentrations and bacterial abundance and diversity were assessed.

Faecal indices were similar in IBS and healthy subjects during habitual diets. The low FODMAP diet was associated with higher faecal pH (7.37 (7.23 to 7.51) vs 7.16 (7.02 to 7.30); p=0.001), similar short-chain fatty acid concentrations, greater microbial diversity and reduced total bacterial abundance (9.63 (9.53 to 9.73) vs 9.83 (9.72 to 9.93) log10 copies/g; p<0.001) compared with the Australian diet. To indicate direction of change, in comparison with the habitual diet the low FODMAP diet reduced total bacterial abundance and the typical Australian diet increased relative abundance for butyrate-producing Clostridium cluster XIVa (median ratio 6.62; p<0.001) and mucus-associated Akkermansia muciniphila (19.3; p<0.001), and reduced Ruminococcus torques.

Diets differing in FODMAP content have marked effects on gut microbiota composition. The implications of long-term reduction of intake of FODMAPs require elucidation.

Resource: Gut. 2014 Jul 12. pii: gutjnl-2014-307264. doi: 10.1136/gutjnl-2014-307264. [Epub ahead of print]

Halmos EP, Christophersen CT, Bird AR, Shepherd SJ, Gibson PR, Muir JG.
2014 July

A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome


Background & Aims: A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) often is used to manage functional gastrointestinal symptoms in patients with irritable bowel syndrome (IBS), yet there is limited evidence of its efficacy, compared with a normal Western diet. We investigated the effects of a diet low in FODMAPs compared with an Australian diet, in a randomized, controlled, single-blind, cross-over trial of patients with IBS.

Methods: In a study of 30 patients with IBS and 8 healthy individuals (controls, matched for demographics and diet), we collected dietary data from subjects for 1 habitual week. Participants then randomly were assigned to groups that received 21 days of either a diet low in FODMAPs or a typical Australian diet, followed by a washout period of at least 21 days, before crossing over to the alternate diet. Daily symptoms were rated using a 0- to 100-mm visual analogue scale. Almost all food was provided during the interventional diet periods, with a goal of less than 0.5 g intake of FODMAPs per meal for the low-FODMAP diet. All stools were collected from days 17–21 and assessed for frequency, weight, water content, and King's Stool Chart rating.

Results: Subjects with IBS had lower overall gastrointestinal symptom scores (22.8; 95% confidence interval, 16.7–28.8 mm) while on a diet low in FODMAPs, compared with the Australian diet (44.9; 95% confidence interval, 36.6–53.1 mm; P < .001) and the subjects' habitual diet. Bloating, pain, and passage of wind also were reduced while IBS patients were on the low-FODMAP diet. Symptoms were minimal and unaltered by either diet among controls. Patients of all IBS subtypes had greater satisfaction with stool consistency while on the low-FODMAP diet, but diarrhea-predominant IBS was the only subtype with altered fecal frequency and King's Stool Chart scores.

Conclusions: In a controlled, cross-over study of patients with IBS, a diet low in FODMAPs effectively reduced functional gastrointestinal symptoms. This high-quality evidence supports its use as a first-line therapy.

Resource: Gastroenterology Volume 146, Issue 1 , Pages 67-75.e5, January 2014

Emma P. Halmos, Victoria A. Power, Susan J. Shepherd, Peter R. Gibson, Jane G. Muir
2014 January