Interpreting FODMAP content of foods in clinical practice.

The article by San Mauro Martin et al raises the important issue of discrepancies in the FODMAP food-composition data published by various sources. The Table compiled by Martin et al provided no indication of serving size, so it is not clear whether the discrepancies reflect true differences in FODMAP content, or simply differences in FODMAP ratings arising from differences in the selected serving size and/or cut-off criteria for high or low content.

Supplementing Dietary Fibers With a Low FODMAP Diet in Irritable Bowel Syndrome: A Randomized Controlled Crossover Trial.

BACKGROUND & AIMS: Institution of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) in patients with irritable bowel syndrome (IBS) may lead to inadequate fiber intake. This trial aimed to investigate the effects of supplementing specific fibers concomitantly with a low FODMAP diet on relevant clinical and physiological indices in symptomatic patients with IBS. METHODS: A double-blind crossover trial was conducted in which 26 patients with IBS were randomly assigned to 1 of 3 low FODMAP diets differing only in total fiber content: control, 23 g/d; sugarcane bagasse, 33 g/d; or fiber combination (sugarcane bagasse with resistant starch), 45 g/d. Each diet lasted 14 days with most food provided and ≥21 days' washout between. Endpoints were assessed during baseline and dietary interventions. RESULTS: From a median IBS Severity Scoring System total score at baseline of 305, all diets reduced median scores by >50 with no differences in rates of symptom response between the diets: control (57%), sugarcane bagasse (67%), fiber combination (48%) (P = .459). Stool output was ∼50% higher during the fiber-supplemented vs control diets (P < .001 for both). While there were no overall differences overall in stool characteristics, descriptors, and water content, or in gastrointestinal transit times, supplementation with sugarcane bagasse normalized both low stool water content and slow colonic transit from during the control diet. CONCLUSIONS: Concomitant supplementation of fibers during initiation of a low FODMAP diet did not alter symptomatic response in patients with IBS but augmented stool bulk and normalized low stool water content and slow transit. Resistant starch did not exert additional symptomatic benefits over sugarcane bagasse alone. (Australia and New Zealand Clinical Trial Registry; Number, ACTRN12619000691145).

Comparing Costs and Outcomes of Treatments for Irritable Bowel Syndrome With Diarrhea: Cost-Benefit Analysis.

BACKGROUND: Irritable bowel syndrome (IBS) is one of the most expensive gastroenterological conditions and is an ideal target for developing a value-based care model. We assessed the comparative cost-benefit of treatments for IBS with diarrhea (IBS-D), the most common IBS subtype from insurer and patient perspectives. METHODS: We constructed a decision analytic model assessing trade-offs among guideline-recommended and recently FDA-approved drugs, supplements, low FODMAP diet, cognitive behavioral therapy (CBT). Outcomes and costs were derived from systematic reviews of clinical trials and national databases. Health-gains were represented using quality-adjusted life years (QALY). RESULTS: From an insurer perspective, on-label prescription drugs (rifaximin, eluxadoline, alosetron) were significantly more expensive than off-label treatments, low FODMAP, or CBT. Insurer treatment preferences were driven by average wholesale prescription drug prices and were not affected by health gains in sensitivity analysis within standard willingness-to-pay ranges up to $150,000/QALY-gained. From a patient perspective, prescription drug therapies and neuromodulators appeared preferable due to a reduction in lost wages due to IBS with effective therapy, and also considering out-of-pocket costs of low FODMAP food and out-of-pocket costs to attend CBT appointments. Comparative health outcomes exerted influence on treatment preferences from a patient perspective in cost-benefit analysis depending on a patients' willingness-to-pay threshold for additional health-gains, but health outcomes were less important than out-of-pocket costs at lower willingness-to-pay thresholds. CONCLUSIONS: Costs are critical determinants of IBS treatment value to patients and insurers, but different costs drive patient and insurer treatment preferences. Divergent cost drivers appear to explain misalignment between patient and insurer IBS treatment preferences in practice.

Diet as a therapeutic tool in chronic gastrointestinal disorders: Lessons from the FODMAP journey.

BACKGROUND AND AIM: Diet is a powerful tool in the management of gastrointestinal disorders, but developing diet therapies is fraught with challenge. This review discusses key lessons from the FODMAP diet journey. METHODS: Published literature and clinical experience were reviewed. RESULTS: Key to designing a varied, nutritionally adequate low-FODMAP diet was our accurate and comprehensive database of FODMAP composition, made universally accessible via our user-friendly, digital application. Our discovery that FODMAPs coexist with gluten in cereal products and subsequent gluten/fructan challenge studies in nonceliac gluten-sensitive populations highlighted issues of collinearity in the nutrient composition of food and confirmation bias in the interpretation of dietary studies. Despite numerous challenges in designing, funding, and executing dietary randomized controlled trials, efficacy of the low-FODMAP diet has been repeatedly demonstrated, and confirmed by real-world experience, giving this therapy credibility in the eyes of clinicians and researchers. Furthermore, real-world application of this diet saw the evolution of a safe and effective three-phased approach. Specialist dietitians must deliver this diet to optimize outcomes as they can target and tailor the therapy and to mitigate the key risks of compromising nutritional adequacy and precipitating disordered eating behaviors, skills outside the gastroenterologist's standard tool kit. While concurrent probiotics are ineffective, specific fiber supplements may improve short-term and long-term outcomes. CONCLUSIONS: The FODMAP diet is highly effective, but optimal outcomes are contingent on the involvement of a gastroenterological dietitian who can assess, educate, and monitor patients and manage risks associated with implementation of this restrictive diet.

Intact cells: "Nutritional capsules" in plant foods.

Macronutrients of pulses or cereals are stored in the cotyledon or endosperm cells with protection from intact cell walls. However, pulses and cereals are generally processed into fine particles during food production. For example, after milling, the macronutrients enclosed in the intact cells are released and are easily accessible to digestive enzymes in the gastrointestinal tract, leading to high metabolic responses. Therefore, studies on the health effects of intact cells and developing an alternative ingredient with a higher proportion of intact cells are areas of emerging interest. In this review, we highlighted the smallest unit of whole grain, an individual cell, as "nutritional capsules" and elucidated the structure-function of the nutritional capsules, followed by isolation techniques, as a potential novel functional ingredient and food. The polysaccharides' monomeric composition, secondary structure, and interactions determine the cell wall properties including the cell detachment during isolation and isolated cell properties. The intact cellular structure is retained after mild food processing and digestion, thereby, contributing to a lower extent/rate of digestion of entrapped macronutrients. Furthermore, the excursed intact capsules in the colonic environment modulate the population and diversity of microbiota, favouring the increased production of the short-chain fatty acids (SCFAs). The structural schematic model of Type-I and Type-II cells is developed together with the schematics of the cell wall isolation process. The review provides a critical summary of the recent trends in intact plant cells as a functional-nutritional food. It paves the way for the industrial production of intact cells as a novel food ingredient.

Dietary fibres and IBS: translating functional characteristics to clinical value in the era of personalised medicine.

Clinical guidelines in the use of fibre supplementation for patients with IBS provide one-size-fits-all advice, which has limited value. This narrative review addresses data and concepts around the functional characteristics of fibre and subsequent physiological responses induced in patients with IBS with a view to exploring the application of such knowledge to the precision use of fibre supplements. The key findings are that first, individual fibres elicit highly distinct physiological responses that are associated with their functional characteristics rather than solubility. Second, the current evidence has focused on the use of fibres as a monotherapy for IBS symptoms overall without attempting to exploit these functional characteristics to elicit specific, symptom-targeted effects, or to use fibre types as adjunctive therapies. Personalisation of fibre therapies can therefore target several therapeutic goals. Proposed goals include achieving normalisation of bowel habit, modulation of gut microbiota function towards health and correction of microbial effects of other dietary therapies. To put into perspective, bulking fibres that are minimally fermented can offer utility in modulating indices of bowel habit; slowly fermented fibres may enhance the activities of the gut microbiota; and the combination of both fibres may potentially offer both benefits while optimising the activities of the microbiota throughout the different regions of the colon. In conclusion, understanding the GI responses to specific fibres, particularly in relation to the physiology of the individual, will be the future for personalising fibre therapy for enhancing the personalised management of patients with IBS.

Contrasting Clinician and Insurer Perspectives to Managing Irritable Bowel Syndrome: Multilevel Modeling Analysis.

INTRODUCTION: Insurance coverage is an important determinant of treatment choice in irritable bowel syndrome (IBS), often taking precedence over desired mechanisms of action or patient goals/values. We aimed to determine whether routine and algorithmic coverage restrictions are cost-effective from a commercial insurer perspective. METHODS: A multilevel microsimulation tracking costs and outcomes among 10 million hypothetical moderate-to-severe patients with IBS was developed to model all possible algorithms including common global IBS treatments (neuromodulators; low fermentable oligo-, di-, and mono-saccharides, and polyols; and cognitive behavioral therapy) and prescription drugs treating diarrhea-predominant IBS (IBS-D) or constipation-predominant IBS (IBS-C) over 1 year. RESULTS: Routinely using global IBS treatments (central neuromodulator; low fermentable oligo-, di-, and mono-saccharides, and polyols; and cognitive behavioral therapy) before US Food and Drug Administration-approved drug therapies resulted in per-patient cost savings of $9,034.59 for IBS-D and $2,972.83 for IBS-C over 1 year to insurers, compared with patients starting with on-label drug therapy. Health outcomes were similar, regardless of treatment sequence. Costs varied less than $200 per year, regardless of the global IBS treatment order. The most cost-saving and cost-effective IBS-D algorithm was rifaximin, then eluxadoline, followed by alosetron. The most cost-saving and cost-effective IBS-C algorithm was linaclotide, followed by either plecanatide or lubiprostone. In no scenario were prescription drugs routinely more cost-effective than global IBS treatments, despite a stronger level of evidence with prescription drugs. These findings were driven by higher prescription drug prices as compared to lower costs with global IBS treatments. DISCUSSION: From an insurer perspective, routine and algorithmic prescription drug coverage restrictions requiring failure of low-cost behavioral, dietary, and off-label treatments appear cost-effective. Efforts to address insurance coverage and drug pricing are needed so that healthcare providers can optimally care for patients with this common, heterogenous disorder.

Screening dietary fibres for fermentation characteristics and metabolic profiles using a rapid in vitro approach: implications for irritable bowel syndrome.

The therapeutic value of specific fibres is partly dependent on their fermentation characteristics. Some fibres are rapidly degraded with the generation of gases that induce symptoms in patients with irritable bowel syndrome (IBS), while more slowly or non-fermentable fibres may be more suitable. More work is needed to profile a comprehensive range of fibres to determine suitability for IBS. Using a rapid in vitro fermentation model, gas production and metabolite profiles of a range of established and novel fibres were compared. Fibre substrates (n 15) were added to faecal slurries from three healthy donors for 4 h with gas production measured using real-time headspace sampling. Concentrations of SCFA and ammonia were analysed using GC and enzymatic assay, respectively. Gas production followed three patterns: rapid (≥60 ml/g over 4 h) for fructans, carrot fibre and maize-derived xylo-oligosaccharide (XOS); mild (30-60 ml/g) for partially hydrolysed guar gum, almond shell-derived XOS and one type of high-amylose resistant starch 2 (RS2) and minimal (no differences with blank controls) for methylcellulose, another high-amylose RS2, acetylated or butyrylated RS2, RS4, acacia gum and sugarcane bagasse. Gas production correlated positively with total SCFA (r 0·80, P < 0·001) and negatively with ammonia concentrations (r -0·68, P < 0·001). Proportions of specific SCFA varied: fermentation of carrot fibre, XOS and acetylated RS2 favoured acetate, while fructans favoured butyrate. Gas production and metabolite profiles differed between fibre types and within fibre classes over a physiologically relevant 4-h time course. Several fibres resisted rapid fermentation and may be candidates for clinical trials in IBS patients.

Effects of fiber intake on intestinal pH, transit, and predicted oral mesalamine delivery in patients with ulcerative colitis.

BACKGROUND AND AIM: Limited data are available on the effects of fermentable fiber in altering intestinal pH and transit to predict efficacy-based delivery profiles of pH-dependent mesalamine coatings in ulcerative colitis (UC). This study aimed to examine regional pH and transit after acute changes in fermentable fiber intake in quiescent UC patients and their effects on drug release systems. METHODS: In a randomized, double-blind study, 18 patients with quiescent UC and 10 healthy controls were supplied meals high (13 g) or low (≤ 2 g) in fermentable fiber and subsequently ingested a wireless pH-motility capsule. After a ≥ 3-day washout, they crossed over to the other diet. Measurements of intestinal pH and transit were used to predict drug release for the various pH-dependent coatings. RESULTS: Increasing fermentable fiber intake lowered overall (median 6.2 [6.1-6.7] vs low: 6.9 [range or interquartile range: 6.4-7.4]; P = 0.01) and distal pH (7.8 [7.3-8.1] vs 8.2 [8.0-8.5]; P = 0.04) in controls. In UC patients, only cecal pH was decreased (high: 5.1 [4.8-5.5] vs low: 5.5 [5.3-5.7]; P < 0.01). Colonic transit in the UC cohort varied widely after a low-fiber intake but tended to normalize after the high fermentable fiber intake. Hypothetical coating dissolution profiles were heterogeneous in UC patients, with a multi-matrix delayed release system having the highest likelihood of patients (20-40%) with incomplete dissolution, and predominant small intestinal dissolution predicted for Eudragit L (94% patients) and S (44-69%). CONCLUSIONS: Patients with quiescent UC have abnormalities in intestinal pH and transit in response to acute changes in fermentable fiber intake. These have potentially detrimental effects on predicted luminal release patterns of pH-dependent 5-aminosalicylic acid release systems.

Effect of a low-FODMAP diet for the management of functional abdominal pain disorders in children: a study protocol for a randomized controlled trial.

BACKGROUND: Evidence from studies in adults documents that fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) may be triggers of symptoms in individuals with functional abdominal pain disorders (FAPDs). However, in children, the evidence is very limited. We aim to assess the effects of a low-FODMAP diet compared with a regular diet for the management of children with FAPDs. METHODS: We will perform a randomized, quadruple-blinded, controlled trial. Seventy-four children aged 8 to 18 years with a FAPD (Irritable Bowel Syndrome or Functional Abdominal Pain-Not Otherwise Specified), diagnosed according to the Rome IV criteria, will be randomly allocated to receive either a low-FODMAP diet or a regular diet for 4 weeks. The primary outcome will be the percentage of the responders, defined as the participants who have at least 30% improvement in abdominal pain intensity on a Visual Analogue Scale (VAS) during the last week of the trial compared with baseline, that is at least equal to the Reliable Change Index (≥ 25 mm change on VAS). Other outcomes will include changes in stool consistency, abdominal pain frequency, total scores on the Gastrointestinal Symptom Rating Scale, KIDSCREEN-10 Index and World Health Organization Five Well-Being Index, child's school attendance and parents' work absenteeism, and BMI-for-age z-score. Compliance, tolerability of the low-FODMAP diet, and adverse events also will be evaluated. Each FAPD subtype will be assessed separately. DISCUSSION: There is a need for high-quality evidence regarding the dietary management of children with FAPDs. This randomized controlled trial (RCT) of rigorous methodological design will help to establish the effectiveness, if any, of a low-FODMAP diet for the management of FAPDs in the pediatric population. The findings of this RCT will assist with the development of guidelines and influence the direction of further research. TRIAL REGISTRATION: NCT04528914 Data and protocol version identifier: 24/08/2020.

The Gut Microbiota and Their Metabolites in Human Arterial Stiffness.

AIM: Gut microbiota-derived metabolites, such as short-chain fatty acids (SCFAs) have vasodilator properties in animal and human ex vivo arteries. However, the role of the gut microbiota and SCFAs in arterial stiffness in humans is still unclear. Here we aimed to determine associations between the gut microbiome, SCFA and their G-protein coupled sensing receptors (GPCRs) in relation to human arterial stiffness. METHODS: Ambulatory arterial stiffness index (AASI) was determined from ambulatory blood pressure (BP) monitoring in 69 participants from regional and metropolitan regions in Australia (55.1% women; mean, 59.8± SD, 7.26 years of age). The gut microbiome was determined by 16S rRNA sequencing, SCFA levels by gas chromatography, and GPCR expression in circulating immune cells by real-time PCR. RESULTS: There was no association between metrics of bacterial α and ß diversity and AASI or AASI quartiles in men and women. We identified two main bacteria taxa that were associated with AASI quartiles: Lactobacillus spp. was only present in the lowest quartile, while Clostridium spp. was present in all quartiles but the lowest. AASI was positively associated with higher levels of plasma, but not faecal, butyrate. Finally, we identified that the expression of GPR43 (FFAR2) and GPR41 (FFAR3) in circulating immune cells were negatively associated with AASI. CONCLUSIONS: Our results suggest that arterial stiffness is associated with lower levels of the metabolite-sensing receptors GPR41/GPR43 in humans, blunting its response to BP-lowering metabolites such as butyrate. The role of Lactobacillus spp. and Clostridium spp., as well as butyrate-sensing receptors GPR41/GPR43, in human arterial stiffness needs to be determined.

Successful elevation of circulating acetate and propionate by dietary modulation does not alter T-regulatory cell or cytokine profiles in healthy humans: a pilot study.

PURPOSE: Increased circulating concentrations of short-chain fatty acids (SCFA) achieved by ingestion of high-fibre diets is associated with anti-inflammatory effects through promotion of FoxP3+ regulatory T(reg) cells in mouse models. This study aimed to determine whether similar increments in blood SCFA levels can be achieved in humans and whether these are associated with similar immune modulatory effects. METHODS: In a pilot single-blinded, randomised, controlled cross-over study in ten healthy subjects, the effects were determined of high- (39 g/day) and low-fibre (18 g/day) intake (all food provided) on SCFA (gas chromatography), proportions of Treg cells (flow cytometry) and a panel of cytokines (multiplex methodology) measured in peripheral blood at day 5 of each diet. RESULTS: Actual fibre intake differed between the diets by 19 [16-21] g/day (P< 0.001). Median [range] total plasma SCFA levels with high-fibre intake were 174.5 [104.8-249.5] µmol/L, which were greater than those associated with low-fibre intake at 59.0 [26.5-79.9] (P < 0.001). Differences were significantly different for both acetate and propionate. The frequencies of total CD4 T cells and T-regulatory cells, and concentrations of inflammatory and anti-inflammatory cytokines were not significantly different between the dietary interventions. CONCLUSIONS: Plasma SCFA levels can be modulated by altering dietary fibre consumption in healthy individuals with increments similar to those achieved in murine studies. Five days of diet intervention did not result in changes in regulatory T-cell proportions and cytokine concentrations in peripheral blood, and may require longer duration of dietary change.

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

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.

Dietary practices and FODMAPs in South Asia: Applicability of the low FODMAP diet to patients with irritable bowel syndrome.

The low Fermentable Oligosaccharides, Disaccharides, and Monosaccharides And Polyols (FODMAP) diet has been described, evaluated, and found efficacious for the treatment of patients with irritable bowel syndrome primarily in Western countries. The aim of this review was to address the applicability of this diet to South Asia. The high prevalence of irritable bowel syndrome in South Asia and its associated effects of quality of life and economics warrant the introduction of efficacious therapies. The considerable heterogeneity of dietary patterns and methods of food preparation across South Asian countries and a paucity of food analysis limit precision in defining foods that are high or low in FODMAPs. Spices and condiments are commonly consumed and mostly have a low FODMAP content. However, major high FODMAP sources are frequently used and include onion, garlic, shallots, legumes/pulses, and wheat-based products, as well as coconut and milk products, offering an opportunity for dietary management to reduce the symptom load. The feasibility of instituting a restrictive diet in which foods with a high FODMAP content are replaced by foods low in FODMAPs must be addressed as a substantial proportion of the nutritional intake including energy, proteins, and micronutrients, is often obtained from FODMAP-rich food. Furthermore, limited knowledge of health professionals together with a paucity of dietitians further challenge the practicality of introducing the diet. Thus, while the use of the low FODMAP diet in South Asia may be more limited than in westernized countries, it does offer potential therapeutic opportunities, the efficacy, and impact of which require further investigation.

FODMAPs: food composition, defining cutoff values and international application.

The low-FODMAP diet is a new dietary therapy for the management of irritable bowel syndrome that is gaining in popularity around the world. Developing the low-FODMAP diet required not only extensive food composition data but also the establishment of "cutoff values" to classify foods as low-FODMAP. These cutoff values relate to each particular FODMAP present in a food, including oligosaccharides (fructans and galacto-oligosaccharides), sugar polyols (mannitol and sorbitol), lactose, and fructose in excess of glucose. Cutoff values were derived by considering the FODMAP levels in typical serving sizes of foods that commonly trigger symptoms in individuals with irritable bowel syndrome, as well as foods that were generally well tolerated. The reliability of these FODMAP cutoff values has been tested in a number of dietary studies. The development of the techniques to quantify the FODMAP content of foods has greatly advanced our understanding of food composition. FODMAP composition is affected by food processing techniques and ingredient selection. In the USA, the use of high-fructose corn syrups may contribute to the higher FODMAP levels detected (via excess fructose) in some processed foods. Because food processing techniques and ingredients can vary between countries, more comprehensive food composition data are needed for this diet to be more easily implemented internationally.

Food components and irritable bowel syndrome.

Ingestion of food has long been linked with gut symptoms, and there is increasing interest in using diet in the management of patients with irritable bowel syndrome (IBS). The West has developed an intense interest in specialized, restrictive diets, such as those that target multiple food groups, avoid gluten, or reduce fermentable oligo-, di-, and mono-saccharides and polyols. However, most gastroenterologists are not well educated about diets or their effects on the gut. It is important to understand the various dietary approaches, their putative mechanisms, the evidence that supports their use, and the benefits or harm they might produce. The concepts behind, and delivery of, specialized diets differ from those of pharmacologic agents. High-quality research is needed to determine the efficacy of different dietary approaches and the place of specific strategies.

Fermentable oligosaccharide, disaccharide, monosaccharide and polyol content of foods commonly consumed by ethnic minority groups in the United Kingdom.

Dietary restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) is an effective management approach for functional bowel disorders; however, its application is limited by the paucity of food composition data available for ethnic minority groups. The aim was to identify and measure the FODMAP content of these commonly consumed foods. According to their perceived importance to clinical practise, the top 20 ranked foods underwent FODMAP analysis using validated analytical techniques (total fructans, Megazyme hexokinase (HK) assay; all others, high-performance liquid chromatography (HPLC) with evaporative light scattering detectors). Of the 20 foods analysed, five were identified as significant sources of at least one FODMAP. Fructans and galacto-oligosaccharides were the major FODMAPs in these foods, including channa dal (0.13 g/100 g; 0.36 g/100 g), fenugreek seeds (1.11 g/100 g; 1.27 g/100 g), guava (0.41 g/100 g; not detected), karela (not detected; 1.12 g/100 g) and tamarind (2.35 g/100 g; 0.02 g/100 g). Broadening the availability of FODMAP composition data will increase the cultural application of low FODMAP dietary advice.

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

OBJECTIVE: 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. DESIGN: 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. RESULTS: 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. CONCLUSIONS: Diets differing in FODMAP content have marked effects on gut microbiota composition. The implications of long-term reduction of intake of FODMAPs require elucidation. TRIAL REGISTRATION NUMBER: ACTRN12612001185853.