Review article: Current status and future directions of ingestible electronic devices in gastroenterology

BACKGROUND

Advances in microelectronics have greatly expanded the capabilities and clinical potential of ingestible electronic devices.

AIM

To provide an overview of the structure and potential impact of ingestible devices in development that are relevant to the gastrointestinal tract.

METHODS

We performed a detailed literature search to inform this narrative review.

RESULTS

Technical success of ingestible electronic devices relies on the ability to miniaturise the microelectronic circuits, sensors and components for interventional functions while being sufficiently powered to fulfil the intended function. These devices offer the advantages of being convenient and minimally invasive, with real-time assessment often possible and with minimal interference to normal physiology. Safety has not been a limitation, but defining and controlling device location in the gastrointestinal tract remains challenging. The success of capsule endoscopy has buoyed enthusiasm for the concepts, but few ingestible devices have reached clinical practice to date, partly due to the novelty of the information they provide and also due to the challenges of adding this novel technology to established clinical paradigms. Nonetheless, with ongoing technological advancement and as understanding of their potential impact emerges, acceptance of such technology will grow. These devices have the capacity to provide unique insight into gastrointestinal physiology and pathophysiology. Interventional functions, such as sampling of tissue or luminal contents and delivery of therapies, may further enhance their ability to sharpen gastroenterological diagnoses, monitoring and treatment.

CONCLUSIONS

The development of miniaturised ingestible microelectronic-based devices offers exciting prospects for enhancing gastroenterological research and the delivery of personalised, point-of-care medicine.

Higher Short-Chain Fermentable Carbohydrates Are Associated with Lower Body Fat and Higher Insulin Sensitivity in People with Prediabetes

The quality of carbohydrates has metabolic consequences in people with prediabetes. However, the causality of short-chain fermentable carbohydrate intakes and metabolic parameters has not been explored in the prediabetic or diabetic population. We investigated associations between different types of carbohydrates, including fermentable oligosaccharides, disaccharides, monosaccharides, polyols (FODMAPs), and polysaccharides (dietary fibre), and body composition and glucose/insulin responses in subjects with prediabetes. In this prospective cross-sectional study, 177 subjects with impaired glucose tolerance (IGT) (mean age: 60 (54-62) years, 41% men) underwent an assessment of body composition and completed six-point oral glucose tolerance tests (OGTT), Homeostatic Model Assessment of Insulin Resistance (HOMA2-IR), insulin sensitivity, detailed 3-day food records, and physical activity questionnaire. Daily habitual FODMAP intake decreased progressively with increasing BMI, ranging from 7.9 (6.2-12.7) g/d in subjects with normal BMI and 6.6 (4.6-9.9) g/d in subjects with overweight to 5.8 (3.8-9.0) g/d in subjects with obesity (p = 0.038). After adjustment for age and gender, galactooligosaccharides (GOSs) were negatively correlated with body fat (Standardised Beta coefficient β = -0.156, p = 0.006) and positively associated with insulin sensitivity (β = 0.243, p = 0.001). This remained significant after adjustment for macronutrients, fibre, and physical activity (p = 0.035 and p = 0.010, respectively). In individuals with IGT, higher dietary GOS intake was associated with lower body fat and higher insulin sensitivity independent of macronutrients and fibre intake, calling for interventional studies to evaluate the effect of FODMAP intake in prediabetes.

A novel Monash Pouch diet in patients with an ileoanal pouch is tolerable and has favorable metabolic luminal effects

Aims

To evaluate a whole-food diet strategy (the Monash Pouch diet [MPD]) designed based on the interacting roles dietary factors play with pouch health. Specifically, its tolerability and acceptability, whether it achieved its dietary and metabolic goals, and the effects on symptoms and inflammation were examined.

Methods

In a 6-week open-label trial, patients with ileoanal pouches educated on the MPD were assessed regarding diet tolerability and acceptance, food intake (7-day food diaries), pouch-related symptoms (clinical pouchitis disease activity index), and, in 24-h fecal samples, calprotectin, fermentative biomarkers, and volatile organic compounds (VOC).

Results

Of 12 patients, 6 male, mean (SD) age 55 (5) and pouch age 13 (2) years, one withdrew with partial small bowel obstruction. Tolerability was excellent in 9 (75%) and acceptance was high (81%). Targeted changes in dietary intake were achieved. Fecal branched- to short-chain fatty acid ratio increased by median 60 [IQR: 11-80]% (P = 0.02). Fecal VOCs for 3 compounds were also increased, 2-methyl-5-propan-2-ylcyclohexa-1,3-diene (Fold-change [FC] 2.08), 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane (FC 3.86), propan-2-ol (FC 2.10). All six symptomatic patients achieved symptomatic remission (P = 0.03). Fecal calprotectin at baseline was 292 [176-527] μg/g and at week 5 was 205 [148-310] μg/g (P = 0.72).

Conclusion

Well tolerated and accepted, the MPD achieved targeted changes in intakes and fermentation of carbohydrates relative to that of protein. There were signals of improvement in symptoms. These results indicate the need for a randomized-controlled trial. (Trial registration: ACTRN12621000374864; https://www.anzctr.org.au/ACTRN12621000374864.aspx).

Detection of changes in regional colonic fermentation in response to supplementing a low FODMAP diet with dietary fibres by hydrogen concentrations, but not by luminal pH

BACKGROUND

Carbohydrate fermentation plays a pivotal role in maintaining colonic health with excessive proximal and deficient distal fermentation being detrimental.

AIMS

To utilise telemetric gas- and pH-sensing capsule technologies for defining patterns of regional fermentation following dietary manipulations, alongside conventional techniques of measuring fermentation.

METHODS

In a double-blind crossover trial, 20 patients with irritable bowel syndrome were fed low FODMAP diets that included no extra fibre (total fibre content 24 g/day), or additional poorly fermented fibre, alone (33 g/day) or with fermentable fibre (45 g/day) for 2 weeks. Plasma and faecal biochemistry, luminal profiles defined by tandem gas- and pH-sensing capsules, and faecal microbiota were assessed.

RESULTS

Plasma short-chain fatty acid (SCFA) concentrations (μmol/L) were median (IQR) 121 (100-222) with fibre combination compared with 66 (44-120) with poorly fermented fibre alone (p = 0.028) and 74 (55-125) control (p = 0.069), but no differences in faecal content were observed. Luminal hydrogen concentrations (%), but not pH, were higher in distal colon (mean 4.9 [95% CI: 2.2-7.5]) with fibre combination compared with 1.8 (0.8-2.8) with poorly fermented fibre alone (p = 0.003) and 1.9 (0.7-3.1) control (p = 0.003). Relative abundances of saccharolytic fermentative bacteria were generally higher in association with supplementation with the fibre combination.

CONCLUSIONS

A modest increase in fermentable plus poorly fermented fibres had minor effects on faecal measures of fermentation, despite increases in plasma SCFA and abundance of fermentative bacteria, but the gas-sensing capsule, not pH-sensing capsule, detected the anticipated propagation of fermentation distally in the colon. The gas-sensing capsule technology provides unique insights into localisation of colonic fermentation.

TRIAL REGISTRATION

ACTRN12619000691145.

Comparison of gastrointestinal landmarks using the gas-sensing capsule and wireless motility capsule

BACKGROUND

Accurate definition of the gastroduodenal and ileocaecal junctions (GDJ, ICJ) is essential for the measurement of regional transit times.

AIMS

To compare the assessment of these landmarks using the novel gas-sensing capsule and validated wireless motility capsule (WMC), and to evaluate intra-subject variance in transit times METHODS: Healthy subjects ingested the gas-sensing capsule and WMC tandemly in random order. Inter-observer agreement was evaluated by intra-class correlation coefficient (ICC). Agreement between the paired devices' transit times was assessed using Bland-Altman analysis; coefficient of variation was performed to express intra-individual variance in transit times. Similar analyses were completed with tandemly ingested gas-sensing capsules.

RESULTS

The inter-observer agreement for landmarks for both capsules was excellent (mean ICC ≥0.97) in 50 studies. The GDJ was identifiable in 92% of the gas-sensing capsule studies versus 82% of the WMC studies (p = 0.27); the ICJ in 96% versus 84%, respectively (p = 0.11). In the primary cohort (n = 26), median regional transit times differed by less than 6 min between paired capsules. Bland-Altman revealed a bias of -0.12 (95% limits of agreement, -0.94 to 0.70) hours for GDJ and - 0.446 (-2.86 to 2.0) hours for ICJ. Similar results were found in a demographically distinct validation cohort (n = 24). For tandemly ingested gas-sensing capsules, coefficients of variation of transit times were 11%-35%, which were similar to variance between the paired gas-sensing capsule and WMC, as were the biases. The capsules were well tolerated.

CONCLUSIONS

Key anatomical landmarks are accurately identified with the gas-sensing capsule in healthy individuals. Intra-individual differences in transit times between capsules are probably due to physiological factors. Studies in populations with gastrointestinal diseases are now required.

Application of The FODMAP Diet in a Paediatric Setting

In adults, dietary management, particularly with the FODMAP diet, is a key evidence-based part of multimodal therapy for patients with disorders of the gut–brain interaction, particularly irritable bowel syndrome. This review aims to describe the evidence for the use of this diet and how to deliver it in paediatric practice. A literature review covering studies on the FODMAP diet in adult and paediatric settings was conducted. While the evidence for the efficacy and safety of a FODMAP diet delivered in three phases, restriction, rechallenge and personalisation, is considerable, there is a lack of good-quality clinical trials exploring the efficacy of the diet in children and adolescents. Likewise, there are limited data on safety concerns associated with a restrictive diet in paediatrics, including impacts on nutrition and growth, disordered eating behaviours, psychosocial and family issues and families and the gut microbiome. The evidence suggests that the implementation of a dietary program is enhanced by a skilled dietitian when navigating a young person (and family) through healthy eating strategies and/or FODMAP restrictions to ameliorate their symptoms. Since the FODMAP diet is being prescribed globally to children, a practical guide for clinicians used to optimise efficacy and safety is provided, including the less restrictive ‘FODMAP-gentle’ diet.

A Randomized Dietary Intervention to Increase Colonic and Peripheral Blood Short-Chain Fatty Acids Modulates the Blood B- and T-cell Compartments in Healthy Humans

BACKGROUND

Short-chain fatty acids (SCFA) have immune-modulating effects in animal models of disease. However, there is limited evidence that this may occur in humans.

OBJECTIVES

This study aimed to determine the effects of increased exposure to SCFA via dietary manipulation on colonic fermentation and adaptive immune cells.

METHODS

Twenty healthy, young adults (18-45 years of age) underwent a blinded, randomized, cross-over dietary intervention, consuming a high-SCFA producing diet and matched low-SCFA diet for 21 days with 21-day wash-out in between. SCFA were provided through resistant starch, inulin and apple cider vinegar. Blood and 3-day total fecal output were collected at baseline and at the end of each diet. Gas chromatography was used to measure fecal and plasma SCFA. Flow cytometry was used for peripheral blood immuno-phenotyping.

RESULTS

High-SCFA diet was associated with significantly (paired samples Wilcoxon test) higher median [IQR] fecal SCFA concentrations (86.6 [59.0] vs 75.4 [56.2] µmol/g, P = 0.02) and significantly lower median fecal ammonia concentrations (26.2 [14.7] vs 33.4 [18.5] µmol/g, P = 0.04) than the low-SCFA diet. Plasma propionate (9.87 [12.3] vs 4.72 [7.6] µmol/L, P = 0.049) and butyrate (2.85 [1.35] vs 2.02 [1.29] µmol/L, P = 0.03) were significantly higher after high-SCFA diet than after low-SCFA diet. Blood total B cells (184 [112] vs 199 [143] cells/µL, P = 0.04), naive B cells (83 [66] vs 95 [89] cells/µL, P = 0.02), Th1 cells (22 [19] vs 29 [16] cells/µL, P = 0.03) and mucosal-associated invariant T (MAIT) cells (62 [83] vs 69 [114] cells/µL, P = 0.02) were significantly lower after high-SCFA diet than low-SCFA diet.

CONCLUSION

Increasing colonic and peripheral blood SCFA has discrete effects on circulating immune cells in healthy humans following 3-week intervention. Further studies, e.g., in patients with inflammatory disease, are necessary to determine if these changes have immunomodulatory effects, whether these are therapeutically beneficial, and whether prolonged intake might be required. Clinical trial registry: Australian New Zealand Clinical trials registry: ACTRN12618001054202. <https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375342&isReview=true>.

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).

How to Implement the 3-Phase FODMAP Diet Into Gastroenterological Practice

Background/Aims

The 3-phase fermentable oligo-, di-, mono-saccharides, and polyols (FODMAP) diet has shown a high level of efficacy in irritable bowel syndrome, largely based on dietitian delivered education. However, access to dietitians can be limited, and challenges exist when applying the diet to a wide range of cultures, such as limited FODMAP analysis of local foods. This review aims to discuss ways to optimally use the FODMAP diet in practice in a wide range of cultures, directed at gastroenterologists from a dietitian's perspective.

Methods

Recent literature was analysed via search databases including Medline, CINAHL, PubMed and Scopus.

Results

The dietetic process involves detailed assessment and follow-up through the 3 stages of the FODMAP diet (restriction, re-introduction, and long-term maintenance). Emerging evidence suggests the diet can be delivered by other health professionals such as the gastroenterologist or nurse, but training on how to do so successfully would be needed. Self-guided approaches through use of technology or specialised food delivery services may be an alternative when dietitians are not available, but efficacy data is limited. Regardless of delivery mode, nutritional and psychological risks of the diet must be mitigated. Additionally, culturally appropriate education must be provided, with accommodations necessary when the FODMAP content of local foods are unknown.

Conclusion

While the diet has shown improved irritable bowel syndrome outcomes across studies, it is important to acknowledge the essential role of dietitians in implementing, tailoring, and managing the diet to achieve the best outcome for each individual.

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.

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.

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.

Dietary Changes Among Breastfeeding Mothers

BACKGROUND

Breastfeeding mothers have been avoiding foods in their diet based on ancient beliefs that it can prevent/reduce unsettled infant crying-fussing behavior.

RESEARCH AIMS

This study aimed to explore (1) the prevalence of maternal dietary changes during the postpartum period; (2) the demographic and infant feeding differences between women who made dietary changes and those who did not; (3) the reasons for dietary change; and (4) what specific foods were avoided.

METHODS

A prospective, cross-sectional 2-group comparison using an online survey mixed-methods design was advertised via social media and Australian websites. Anonymous volunteers who were presently breastfeeding or had breastfed for any length of time in the past were eligible.

RESULTS

Of 1,262 participants, 966 (77%) avoided foods/beverages in their diet. The most commonly avoided beverages were alcohol (79%) and coffee (44%), and the most commonly avoided foods were chili (22%), milk-chocolate (22%), cabbage (20%), onion (20%), and garlic (16%). Reasons for dietary avoidance related to baby being unsettled (31%), baby having wind/gas (29%), colic (11%), and crying (10%). Of 245 participants who removed dairy, 80 (33%) did not substitute with calcium-rich alternatives. Food and beverage avoidance commenced as early as 1 week postpartum and continued until mean (SD) infant age of 9 (5) months.

CONCLUSIONS

It is commonplace for breastfeeding mothers to avoid foods and beverages for reasons associated with infantile colic. Of major concern is the duration of food avoidance during a time of increased nutritional requirements. This information may assist in improving the nutritional support given to breastfeeding mothers.

Microbial Interventions to Control and Reduce Blood Pressure in Australia (MICRoBIA): rationale and design of a double-blinded randomised cross-over placebo controlled trial

Background

Hypertension is a prevalent chronic disease worldwide that remains poorly controlled. Recent studies support the concept that the gut microbiota is involved in the development of hypertension and that dietary fibre intake may act through the gut microbiota to lower blood pressure (BP). Resistant starch is a type of prebiotic fibre which is metabolised by commensal bacteria in the colon to produce short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate. Previous work in pre-clinical models provides strong evidence that both prebiotic fibre as well as SCFAs (i.e. postbiotics) can prevent the development of hypertension. The aim of this clinical trial is to determine if acetylated and butyrylated modified resistant starch can decrease BP of hypertensive individuals via the modulation of the gut microbiota and release of high levels of SCFAs.

Methods

This is a phase IIa double-blinded, randomised, cross-over, placebo controlled trial. Participants are randomly allocated to receive either a diet containing 40 g/day of the modified resistant starch or placebo (corn starch or regular flour) for 3 weeks on each diet, with a 3-week washout period between the two diets. BP is measured in the office, at home, and using a 24-h ambulatory device. Arterial stiffness is measured using carotid-to-femoral pulse wave velocity. Our primary endpoint is a reduction in ambulatory daytime systolic BP. Secondary endpoints include changes to circulating cytokines, immune markers, and modulation to the gut microbiome.

Discussion

The findings of this study will provide the first evidence for the use of a combination of pre- and postbiotics to lower BP in humans. The results are expected at the end of 2021.

Trial registration

Australia and New Zealand Clinical Trial Registry ACTRN12619000916145. Registered on 1 July 2019.

Naturally-occurring dietary salicylates in the genesis of functional gastrointestinal symptoms in patients with irritable bowel syndrome: Pilot study

Background and Aim

An elimination‐rechallenge dietary approach targeting naturally‐occurring bioactive chemicals has been proposed to alleviate functional gastrointestinal symptoms. A major focus of this approach is salicylates. This study aimed to address the potential role of dietary salicylates in the induction of symptoms in patients with irritable bowel syndrome (IBS).

Methods

A pilot, double‐blind, randomized, cross‐over trial of 2‐week low‐ versus high‐salicylate diets (6.6 and 27.9 g/day salicylate, respectively) was undertaken. All foods were provided containing minimal quantities of other potential food triggers. Gastrointestinal and extraintestinal symptoms were measured daily using a 100‐mm visual‐analogue‐scale.

Results

Ten participants with IBS completed the study, including one with known aspirin‐sensitivity. Overall, no differences in symptoms were observed (P = 0.625; Friedman test). However, clear symptom provocation was seen in the aspirin‐sensitive participant, with all abdominal symptoms and tiredness worsening during the high‐salicylate diet. A similar trend was seen in another participant, where abdominal symptoms gradually worsened during the high‐salicylate diet.

Conclusions

These results provide some evidence that food‐related salicylates may influence the genesis of symptoms in a subset of patients with IBS. A larger cohort is needed to determine the incidence of salicylate‐sensitivity and further evaluate the diet as a potential therapeutic target.

The protocol was registered at www.anzctr.org.au (ACTRN12620001250921).

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.

High Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) Consumption Among Endurance Athletes and Relationship to Gastrointestinal Symptoms

Endurance athletes commonly experience lower gastrointestinal (GI) symptoms similar to those of irritable bowel syndrome (IBS). Previous research on the restriction of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP), a diet-based mitigation strategy initially developed for IBS, has shown promise for application in athlete populations. Athlete's dietary strategies surrounding exercise have not been formally assessed in relation to FODMAP content of foods or sports nutrition products. Additionally, the FODMAP content of athlete's habitual diets has not been examined in larger sample sizes. This research aims to investigate the FODMAP content of endurance athlete diets by examining these three areas, in conjunction with GI symptoms. Dietary habits surrounding exercise and GI symptoms were examined in 430 endurance athletes using a previously validated Endurance Athlete Questionnaire. A subset of athletes (n = 73) completed a FODMAP-specific food frequency questionnaire for habitual intake. The most commonly reported sports nutrition products were analyzed for FODMAP content using standardized analytical methods. Mean habitual intakes were compared to previous FODMAP studies and medians were compared between those with and without lower GI symptoms. Athletes commonly consumed high FODMAP foods during pre-race dinners and breakfasts, with over 60% reporting specific high FODMAP foods. More frequent nutrition product use, particularly solid, gel/gummy, and homemade products, was often related to increased frequency of GI symptoms. Of the sixteen commonly used sports nutrition products tested, seven were high FODMAP in one serving. All but one of the remaining products became high FODMAP when consumed in multiple servings, as is likely the case during endurance exercise. Average habitual FODMAP intake was 26.1 g (±15.9 g), similar to intakes classified as high FODMAP in previous research on FODMAPs and IBS or GI symptoms. Only 15.1% of athletes consumed a diet that would be considered low in FODMAP. Exploratory analyses showed higher intake of some FODMAP types among athletes exhibiting various lower GI symptoms. Overall, this study demonstrated that FODMAP intake by endurance athletes is high both surrounding exercise and habitually, and may be contributing to GI symptoms experienced during exercise. This information can be utilized when analyzing athlete diets and selecting foods to decrease GI symptoms.

Delivery of Acetate to the Peripheral Blood after Consumption of Foods High in Short-Chain Fatty Acids

SCOPE

To promote local and systemic benefits of short-chain fatty acids (SCFA), methods of increasing their delivery to the gastrointestinal tract are needed. SCFA in foods and beverages represents a poorly characterized source. Main aims of this study are: 1) quantify SCFA in commonly consumed foods and beverages, and 2) explore the pharmacokinetics of consuming oral SCFA from dietary sources.

METHODS AND RESULTS

Gas-chromatography coupled to flame ionization detection is used measure SCFA in 38 commonly consumed foods and beverages. Acetate is the most abundant SCFA detected, with kombucha and vinegar found to provide >1000 mg of acetate per serve. An acute pharmacokinetic study is conducted in 10 participants. Acetate is stable across the 2-h sampling period after consumption of a control drink, with consumption of a vinegar drink containing 25 mmol acetate significantly increasing plasma acetate concentration after 60 min and increasing acetate delivery to the blood upon assessment of the area under the pharmacokinetic curve.

CONCLUSION

Fermented foods and beverages are a natural source of dietary SCFA that acutely deliver SCFA to the blood. If systemic delivery is needed for immunological and metabolic effects to occur, these may be achieved if delivered over a longer period of time.

Pharmacologic, Dietary, and Psychological Treatments for Irritable Bowel Syndrome With Constipation: Cost Utility Analysis

Introduction. Irritable bowel syndrome (IBS) is the most common gastroenterology referral and one of the most common gastrointestinal complaints in primary care. We performed a cost-utility analysis of the most common treatments available in general practice for IBS with constipation (IBS-C), the most expensive IBS subtype. Methods. We developed a decision analytic model evaluating guideline-recommended and Food and Drug Administration-approved drugs, supplements, and dietary/psychological interventions. Model inputs were derived from "global symptom improvement" outcomes in systematic reviews of clinical trials. Costs were derived from national datasets. Analysis was performed with a 1-year time horizon from patient and payer perspectives. We analyzed a prototypical managed-care health plan with no cost-sharing to the patient. Results. From a payer perspective, global IBS treatments (including low FODMAP, cognitive behavioral therapy [CBT], neuromodulators), which are not specific to the IBS-C bowel subtype were less expensive than on-label prescription drug treatments. From a patient perspective, on-label prescription drug treatment with linaclotide was the least expensive treatment strategy. Drug prices and costs to manage untreated IBS-C were most important determinants of payer treatment preferences. Effects of treatment on missed work-days and need for repeated appointments to complete treatment were the most important determinants of treatment preference to patients. Discussion. Due mostly to prescription drug prices, neuromodulators, low FODMAP, and CBT appear cost-effective compared to on-label drug treatments from a payer perspective in cost-utility analysis. These findings may explain common treatment barriers in clinical practice.

Review article: FODMAPS, prebiotics and gut health-the FODMAP hypothesis revisited

BACKGROUND

Restriction of dietary FODMAP intake can alleviate symptoms in patients with irritable bowel syndrome. Because many FODMAPs have prebiotic actions, there is concern that their dietary restriction leads to dysbiosis with health consequences, and their intake is being encouraged by addition to foods and via supplements.

AIMS

To examine the hazards and benefits of high and low FODMAP intake.

METHODS

Current literature was reviewed and alternative hypotheses formulated.

RESULTS

Low FODMAP intake reduces abundance of faecal Bifidobacteria without known adverse outcomes and has no effect on diversity, but the reduction in bacterial density may potentially be beneficial to gut health. Supplementary prebiotics can markedly elevate the intake of FODMAPs over levels consumed in the background diet. While this increases the abundance of Bifidobacteria, it adversely affects gut health in animal studies by inducing colonic mucosal barrier dysfunction, mucosal inflammation and visceral hypersensitivity. Rapid colonic fermentation is central to the identified mechanisms that include injury from high luminal concentrations of short-chain fatty acids and low pH, and inflammatory effects of increased endotoxin load and glycation of macromolecules. Whether these observations translate into humans requires further study. Opposing hypotheses are presented whereby excessive intake of FODMAPs might have health benefits via prebiotic effects, but might also be injurious and contribute to the apparent increase in functional intestinal disorders.

CONCLUSIONS

Reduced FODMAP intake has few deleterious effects on gut microbiota. Consequences (both positive and negative) of excessive carbohydrate fermentation in the human intestines from elevated FODMAP intake require more attention.

Implementation of the low FODMAP diet in functional gastrointestinal symptoms: A real-world experience

BACKGROUND

The low FODMAP (fermentable oligo-, di-, monosaccharides, and polyols) diet reduces functional gastrointestinal symptoms (FGID) when implemented by dietitian-delivered education in clinical trials, but it is unknown how well the diet is followed in routine clinical care and if differences exist when implemented by physician or dietitian. This study aimed to evaluate the real-world experience of patients recommended the diet.

METHODS

This case-series interviewed FGID patients attending a gastroenterology clinic with previous recommendation to trial the low FODMAP diet, examining who recommended the diet and what their percentage improvement was. To evaluate implementation of the diet's 3 phases, questions were constructed based on current literature and clinical guidelines regarding length of initial restriction and food knowledge (Phase-1), number of foods re-challenged (Phase-2) and food re-introduction as tolerated (Phase-3). The comprehensive nutrition assessment questionnaire provided daily FODMAP intake. Data were analyzed using chi-squared tests.

KEY RESULTS

In 80 patients (21 male), the diet was recommended by the gastroenterologist in 53%, general practitioner 22%, dietitian 9% and other 15%. 30% saw a dietitian for guidance. 55% reported a ≥50% symptom improvement. The diet was followed appropriately during Phase-1 by 78% (with vs without a dietitian, 96% vs 71%; P = .02), Phase-2 by 48% (70% vs 39%; P = .02) and Phase-3 by 40% (65% vs 29%; P < .01). A FODMAP intake of <12 g/d (considered therapeutic) was achieved by 44% (72% vs 31%; P < .01).

CONCLUSIONS & INFERENCES

Symptom improvement was reported in half of patients, but many did not reach the therapeutic FODMAP intake target, especially without dietitian education. Compliance was poor in Phase-2 and Phase-3 but improved with dietitian guidance.

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.

The impact of dietary fermentable carbohydrates on a postinflammatory model of irritable bowel syndrome

BACKGROUND

A low fermentable carbohydrate (FODMAP) diet is used in quiescent inflammatory bowel disease when irritable bowel syndrome-like symptoms occur. There is concern that the diet could exacerbate inflammation by modifying microbiota and short-chain fatty acid (SCFA) production. We examined the effect of altering dietary FODMAP content on inflammation in preclinical inflammatory models.

METHODS

C57BL/6 mice were given 3% dextran sodium sulfate (DSS) in drinking water for 5 days and recovered for 3 weeks (postinflammatory, n = 12), or 5 days (positive-control, n = 12). Following recovery, DSS-treated or control mice (negative-control, n = 12) were randomized to 2-week low- (0.51 g/100 g total FODMAP) or high-FODMAP (4.10 g) diets. Diets mimicked human consumption containing fructose, sorbitol, galacto-oligosaccharide, and fructan. Colons were assessed for myeloperoxidase (MPO) activity and histological damage. Supernatants were generated for perforated patch-clamp recordings and cytokine measurement. Cecum contents were analyzed for microbiota, SCFA, and branched-chain fatty acids (BCFA). Data were analyzed by two-way ANOVA with Bonferroni.

KEY RESULTS

Inflammatory markers were higher in the positive-control compared with negative-control and postinflammatory groups, but no differences occurred between the two diets within each treatment (MPO P > .99, histological scores P > .99, cytokines P > .05), or the perforated patch-clamp recordings (P > .05). Microbiota clustered mainly based on DSS exposure. No difference in SCFA content occurred. Higher total BCFA occurred with the low-FODMAP diet in positive-control (P < .01) and postinflammatory groups (P < .01).

CONCLUSIONS AND INFERENCES

In this preclinical study, reducing dietary FODMAPs did not exacerbate nor mitigate inflammation. Microbiota profile changes were largely driven by inflammation rather than diet. Low FODMAP intake caused a shift toward proteolytic fermentation following inflammation.

Randomised clinical trial: reducing the intake of dietary FODMAPs of breastfeeding mothers is associated with a greater improvement of the symptoms of infantile colic than for a typical diet

BACKGROUND

Therapeutic diets for infantile colic lack evidence. In breastfed infants, avoiding "windy" foods by the breastfeeding mother is common.

AIM

To examine the effects of a maternal low-FODMAP (Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, And Polyols) diet compared to a typical-Australian diet on infant crying-fussing durations of infants with colic in a randomised, double-blind, crossover feeding study.

METHODS

Between 2014 and 2016 exclusively breastfed infants aged ≤9 weeks meeting Wessel criteria for colic were recruited. Mothers were provided a 10-day low-FODMAP or typical-Australian diet, then alternated without washout. Infants without colic (controls) were observed prospectively and mothers remained on habitual diet. Infant crying-fussing durations were captured using a Barr Diary. Measures of maternal psychological status and samples of breast milk and infant faeces were collected.

RESULTS

Mean crying-fussing durations were 91 min/d in seven controls compared with 269 min/d in 13 colicky infants (P < 0.0001), which fell by median 32% during the low-FODMAP diet compared with 20% during the typical-Australian diet (P = 0.03), confirmed by a two-way mixed-model analyses-of-variance (ƞ_p ²  = 0.719; P = 0.049) with no order effect. In breast milk, lactose concentrations remained stable and other known dietary FODMAPs were not detected. Changes in infant faecal calprotectin were similar between diets and groups, and faecal pH did not change. Median maternal anxiety and stress fell with the typical-Australian diet (P < 0.01), but remained stable on the low-FODMAP diet.

CONCLUSIONS

Maternal low-FODMAP diet was associated with enhanced reduction in crying-fussing durations of infants with colic. This was not related to changes in maternal psychological status, gross changes in breast milk or infant faeces. Mechanisms require elucidation. Trial Registration Australian New Zealand Clinical Trials Registry (ANZCTR): 12616000512426 - anzctr.org.au.

Gluten-free and low-FODMAP sourdoughs for patients with coeliac disease and irritable bowel syndrome: A clinical perspective

Wheat- and gluten-containing products are often blamed for triggering a wide range of gastrointestinal symptoms, and this has fueled demand for gluten-free products worldwide. The best studied 'gluten intolerance' is coeliac disease, an auto-immune disease that affects the small intestine. Coeliac disease occurs in 1% of the population and requires strict, life-long avoidance of gluten-containing foods as the only medical treatment. There is a larger group of individuals (around 10-15% of the population) who report a wide-range of gastrointestinal symptoms that respond well to a 'gluten-free diet', but who do not have coeliac disease - so called 'non-coeliac gluten sensitivity (NCGS)'. The team at Monash University has identified other factors in gluten-containing foods that may be responsible for symptoms in this group of individuals with so-called, NCGS. We have evidence that certain poorly absorbed short chain carbohydrates (called FODMAPs) present in many gluten-containing food products, induce symptoms of abdominal pain, bloating, wind and altered bowel habit (associated with irritable bowel syndrome, IBS). Our research has shown that FODMAPs, and not gluten, triggered symptoms in NCGS. Going forward, there are great opportunities for the food industry to develop low FODMAP products for this group, as choice of grain variety and type of food processing technique can greatly reduce the FODMAP levels in foods. The use of sourdough cultures in bread making has been shown to reduce the quantities of FODMAPs (mostly fructan), resulting in bread products that are well tolerated by patients with IBS. Greater interaction between biomedical- and food-scientists will improve understanding about the clinical problems many consumers face, and lead to the development of food products that are better tolerated by this group.

The safety and sensitivity of a telemetric capsule to monitor gastrointestinal hydrogen production in vivo in healthy subjects: a pilot trial comparison to concurrent breath analysis

BACKGROUND

Intestinal gases are currently used for the diagnosis of disorders including small intestinal bacterial overgrowth and carbohydrate malabsorption.

AIM

To compare the performance of measuring hydrogen production within the gut directly with the telemetric gas-sensing capsule with that of indirect measurement through breath testing.

METHODS

Using standard breath testing protocols, the capsules and breath tests were simultaneously evaluated in a single-blinded trial in 12 healthy subjects. Eight received a single dose of 1.25-40 g inulin and four 20 or 40 g glucose. Safety and reliability of the capsules were also assessed.

RESULTS

There were no reported adverse events. All capsules were retrieved and operated without failure. Capsule measurements were in agreement with breath test measurements in magnitude but not in timing; minimal hydrogen production was observed after glucose ingestion and capsule measurements correlated with breath hydrogen after ingestion of 40 g inulin. A dose-dependent increase in concentration of hydrogen was observed from the capsule following ingestion of inulin as low as 1.25 g compared with >10 g for breath measurements. Specifically, the capsule measured >3000 times higher concentrations of hydrogen compared to breath tests, resulting in a signal-to-noise ratio of 23.4 for the capsule compared to 4.2 for the breath test.

CONCLUSIONS

The capsule showed high sensitivity and signal-to-noise ratio in measuring luminal hydrogen concentrations, provided information on the site of intestinal gas production, and demonstrated safety and reliability. The capsule has potential for improving diagnostic precision for disorders such as small intestinal bacterial overgrowth.

Culture- and metagenomics-enabled analyses of the Methanosphaera genus reveals their monophyletic origin and differentiation according to genome size

The genus Methanosphaera is a well-recognized but poorly characterized member of the mammalian gut microbiome, and distinctive from Methanobrevibacter smithii for its ability to induce a pro-inflammatory response in humans. Here we have used a combination of culture- and metagenomics-based approaches to expand the representation and information for the genus, which has supported the examination of their phylogeny and physiological capacity. Novel isolates of the genus Methanosphaera were recovered from bovine rumen digesta and human stool, with the bovine isolate remarkable for its large genome size relative to other Methanosphaera isolates from monogastric hosts. To substantiate this observation, we then recovered seven high-quality Methanosphaera-affiliated population genomes from ruminant and human gut metagenomic datasets. Our analyses confirm a monophyletic origin of Methanosphaera spp. and that the colonization of monogastric and ruminant hosts favors representatives of the genus with different genome sizes, reflecting differences in the genome content needed to persist in these different habitats.

Review article: short chain fatty acids as potential therapeutic agents in human gastrointestinal and inflammatory disorders

BACKGROUND

Butyrate, propionate and acetate are short chain fatty acids (SCFA), important for maintaining a healthy colon and are considered as protective in colorectal carcinogenesis. However, they may also regulate immune responses and the composition of the intestinal microbiota. Consequently, their importance in a variety of chronic inflammatory diseases is emerging.

AIMS

To review the physiology and metabolism of SCFA in humans, cellular and molecular mechanisms by which SCFA may act in health and disease, and approaches for therapeutic delivery of SCFA.

METHODS

A PubMed literature search was conducted for clinical and pre-clinical studies using search terms: 'dietary fibre', short-chain fatty acids', 'acetate', 'propionate', 'butyrate', 'inflammation', 'immune', 'gastrointestinal', 'metabolism'.

RESULTS

A wide range of pre-clinical evidence supports roles for SCFA as modulators of not only colonic function, but also multiple inflammatory and metabolic processes. SCFA are implicated in many autoimmune, allergic and metabolic diseases. However, translating effects of SCFA from animal studies to human disease is limited by physiological and dietary differences and by the challenge of delivering sufficient amounts of SCFA to the target sites that include the colon and the systemic circulation. Development of novel targeted approaches for colonic delivery, combined with postbiotic supplementation, may represent desirable strategies to achieve adequate targeted SCFA delivery.

CONCLUSIONS

There is a large array of potential disease-modulating effects of SCFA. Adequate targeted delivery to the sites of action is the main limitation of such application. The ongoing development and evaluation of novel delivery techniques offer potential for translating promise to therapeutic benefit.

Modulation of colonic hydrogen sulfide production by diet and mesalazine utilizing a novel gas-profiling technology

Excessive hydrogen sulfide (H₂S) production from gut microbial metabolism may have clinically important relevance in the pathogenesis of gut disorders, including ulcerative colitis. However, little is known regarding factors that alter its production. Using a newly-designed in vitro gas-profiling technology, the study aimed to verify real-time H₂S measurement reproducibility and thereafter, assess its production following exposure to dietary factors and 5-aminosalicylate acid (5-ASA). Measurements of H₂S, carbon dioxide, hydrogen and methane measurements were compared between gas-profiling systems. Homogenized slurries were prepared from freshly-passed healthy human feces. Fifty ml slurries were aliquoted into separate fermentation chambers and substrates added including 1 g highly fermentable fructo-oligosaccharides (FOS) or resistant starch Hi-Maize (RS), or minimally fermentable psyllium or sterculia, 1 g cysteine, 0.9 g sodium sulfate or 1.2 mL of 1 M 5-ASA alone or in combinations. H₂S release was sampled every 5 mins over 4-h and expressed relative to unspiked controls. RS suppressed H₂S production by a mean 89.0 (SEM 4.8)% and FOS by 82.2 (6.2)% compared to <35 (17)% by psyllium and sterculia (p<0.001, two-way ANOVA). Cysteine stimulated H₂S production by 1557 (532)%. The addition of FOS to slurries containing cysteine significantly suppressed H₂S by 90 (2)% over the addition of 5-ASA (0.3 (2)%, p<0.001). Sulfate and 5-ASA had minimal overall effects. In conclusion, the H₂S-profiling technology is a reproducible tool. Production of H₂S is greatly enhanced by sulfur-amino acids but not inorganic sulfate, and is effectively suppressed by readily fermentable fibers. These findings inform potential designs of dietary therapies to reduce H₂S production in vivo.

Inaccuracy of patient-reported descriptions of and satisfaction with bowel actions in irritable bowel syndrome

BACKGROUND

Perception of diarrhea and constipation differs greatly. This study aimed to correlate subjective and objective assessment of fecal characteristics in irritable bowel syndrome (IBS) patients.

METHODS

Data from two interventional dietary trials with varying FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) or gluten content were interrogated. Subjects rated their dissatisfaction with stool consistency daily using a visual analog scale during the interventions. Subjects collected stools at the end of each intervention. Each stool was scored according to the King's Stool Chart (KSC). Fecal water content (FWC) was measured on pooled feces by freeze drying, with diarrhea defined as ≥78%.

KEY RESULTS

Seventy IBS (Rome III) and eight healthy subjects were studied. Each subject's self-rating of stool consistency during the most symptomatic diet was approximately double that of their least. Degree of dissatisfaction with stool consistency correlated poorly with changes in FWC and KSC. IBS subtype related poorly to objective measures of stool consistency. Sixty percent of IBS-D subjects had diarrhea on objective measures. Eighty-five percent with IBS-C had hard and formed stools but three patients met the criteria for diarrhea. One healthy subject had diarrhea on FWC and KSC, and six had hard, formed stools. No differences in FWC was observed when subjects consumed differing amounts of FODMAPs or gluten (all P > .200).

CONCLUSIONS AND INFERENCES

There are major disparities between patients' stool descriptions and objective features of constipation and diarrhea. Patient-reported bowel habits require more interrogation for accurate IBS subtyping. Varying FODMAP or gluten content of the diet is not associated with consistent change in FWC.

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.

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.

Gastrointestinal Symptoms and FODMAP Intake of Aged-Care Residents from Christchurch, New Zealand

Studies on fermentable oligo-, di-, and monosaccharides as well as polyols (FODMAPs) intake in older adults are lacking. This study investigated the relationship between gastrointestinal (GI) symptoms and FODMAPs in aged care residents. The Gastrointestinal Symptom Rating Score questionnaire modified for patients with IBS (GSRS-IBS) was used to identify participants with IBS-like symptoms. Dietary intake was assessed for a subgroup of participants with highest total GSRS-IBS score (symptomatic cases) and age, sex, and level of care matched participants with low total GSRS-IBS score (asymptomatic controls). Seventy-four participants with a mean (SD) age of 86 (6.6) years completed the GSRS-IBS questionnaire and dietary data were collected using food diaries from a subsample of 27 symptomatic and 27 asymptomatic participants. The study found many older adults with functional gut symptoms. There were no differences between the groups for FODMAP intake and no significant relationship was found between FODMAP intake and total GSRS-IBS score. Lactose from milk and milk-based desserts was the biggest FODMAP contributor (16 g/day) and a significant relationship between total FODMAP intake and diarrhoea was found. A larger study sample in future studies is required to better capture symptomatic cases and manipulation of dietary FODMAPs may assist with the management of IBS in the elderly.

Reducing the maternal dietary intake of indigestible and slowly absorbed short-chain carbohydrates is associated with improved infantile colic: a proof-of-concept study

BACKGROUND

To investigate if a low fermentable oligo-, di- and mono-saccharides and polyols (FODMAP) diet consumed by breastfeeding mothers may be associated with reduced symptoms of infantile colic.

METHODS

Exclusively breastfeeding mothers and their typically-developing healthy infants who met the Wessel Criteria for infantile colic were recruited from the community, to this single-blind, open-label, interventional study. After a 3-day qualifying period, mothers were provided a low FODMAP 7-day diet. On days 5, 6 and 7 mothers completed a Baby Day Diary. At baseline and at the end of the 7-day dietary intervention, breast milk was analysed for FODMAP content and infant faecal samples for pH.

RESULTS

Eighteen breastfeeding mothers (aged 27-40 years) adhered (100%) to the low FODMAP diet. Infants were of gestational age 37-40.3 weeks and aged 2-17 weeks. At entry, crying durations were a mean [95% CI] of 142 [106-61] min and fell by 52 [178-120] min (P = 0.005; ancova). Combined crying-fussing durations fell by 73 [301-223] min (n = 13; P = 0.007), as did crying episodes (P = 0.01) and fussing durations (P = 0.011). Infant sleeping, feeding, or awake-and-content durations did not change. Infant faecal pH did not change. Breast milk lactose content was stable and other known FODMAPs were not detected. At end of study, mothers reported their baby 'is much more content' and 'can be put down without crying'.

CONCLUSIONS

Maternal low FODMAP diet may be associated with a reduction in infant colic symptoms. A randomized controlled study is warranted to determine if a maternal low FODMAP diet is effective in reducing symptoms.

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.

Controversies and Recent Developments of the Low-FODMAP Diet

The low-fermentable oligo-, di-, and monosaccharide and polyol (FODMAP) diet is a 2-phased intervention, with strict reduction of all slowly absorbed or indigestible short-chain carbohydrates (ie, FODMAPs) followed by reintroduction of specific FODMAPs according to tolerance. The efficacy of the elimination phase of the FODMAP diet is well established, but the success of maintaining this diet has been shown in only a few observational studies. How the efficacy of the low-FODMAP diet compares with that of other therapies has received limited attention, but recent studies have shown this diet to be comparable or superior to diets that address eating style and choice of food as well as to gut hypnotherapy. There has been no comparison between the low-FODMAP diet and the gluten-free diet, which moderately reduces FODMAP intake. Mechanistically, dietary FODMAPs have very limited effects on the consistency of bowel actions but seem to suppress the release of histamine. Neither symptom pattern nor breath hydrogen testing for fructose or polyol malabsorption is a useful predictor of efficacy, but analysis of gut microbiota has potential. As a restrictive diet, the low-FODMAP diet carries risks of nutritional inadequacy and of fostering disordered eating, which has received little attention. Strict FODMAP restriction induces a potentially unfavorable gut microbiota, although the impact of this consequence upon health is unknown. This observation puts additional impetus on the reintroduction of FODMAPs according to tolerance during the maintenance phase of the diet. Studies of the low-FODMAP diet in children are few but do suggest benefit. However, such a strategy should be implemented with care due to the psychological and nutritional risks of a restrictive diet. Clinical wisdom is required in utilizing the low-FODMAP diet.

Adding glucose to food and solutions to enhance fructose absorption is not effective in preventing fructose-induced functional gastrointestinal symptoms: randomised controlled trials in patients with fructose malabsorption

BACKGROUND

In healthy individuals, the absorption of fructose in excess of glucose in solution is enhanced by the addition of glucose. The present study aimed to assess the effects of glucose addition to fructose or fructans on absorption patterns and genesis of gastrointestinal symptoms in patients with functional bowel disorders.

METHODS

Randomised, blinded, cross-over studies were performed in healthy subjects and functional bowel disorder patients with fructose malabsorption. The area-under-the-curve (AUC) was determined for breath hydrogen and symptom responses to: (i) six sugar solutions (fructose in solution) (glucose; sucrose; fructose; fructose + glucose; fructan; fructan + glucose) and (ii) whole foods (fructose in foods) containing fructose in excess of glucose given with and without additional glucose. Intake of fermentable short chain carbohydrates (FODMAPs; fermentable, oligo-, di-, monosaccharides and polyols) was controlled.

RESULTS

For the fructose in solution study, in 26 patients with functional bowel disorders, breath hydrogen was reduced after glucose was added to fructose compared to fructose alone [mean (SD) AUC 92 (107) versus 859 (980) ppm 4 h^-1 , respectively; P = 0.034). Glucose had no effect on breath hydrogen response to fructans (P = 1.000). The six healthy controls showed breath hydrogen patterns similar to those with functional bowel disorders. No differences in symptoms were experienced with the addition of glucose, except more nausea when glucose was added to fructose (P = 0.049). In the fructose in foods study, glucose addition to whole foods containing fructose in excess of glucose in nine patients with functional bowel disorders and nine healthy controls had no significant effect on breath hydrogen production or symptom response.

CONCLUSIONS

The absence of a favourable response on symptoms does not support the concomitant intake of glucose with foods high in either fructose or fructans in patients with functional bowel disorders.

Randomised clinical trial: the efficacy of gut-directed hypnotherapy is similar to that of the low FODMAP diet for the treatment of irritable bowel syndrome

BACKGROUND

A low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet is effective in treating irritable bowel syndrome (IBS).

AIM

To compare the effects of gut-directed hypnotherapy to the low FODMAP diet on gastrointestinal symptoms and psychological indices, and assess additive effects.

METHODS

Irritable bowel syndrome patients were randomised (computer-generated list), to receive hypnotherapy, diet or a combination. Primary end-point: change in overall gastrointestinal symptoms across the three groups from baseline to week 6. Secondary end-points: changes in psychological indices, and the durability of effects over 6 months.

RESULTS

Of 74 participants, 25 received hypnotherapy, 24 diet and 25 combination. There were no demographic differences at baseline across groups. Improvements in overall symptoms were observed from baseline to week 6 for hypnotherapy [mean difference (95% CI): -33 (-41 to -25)], diet [-30 (-42 to -19)] and combination [-36 (-45 to -27)] with no difference across groups (P = 0.67). This represented ≥20 mm improvement on visual analogue scale in 72%, 71% and 72%, respectively. This improvement relative to baseline symptoms was maintained 6 months post-treatment in 74%, 82% and 54%. Individual gastrointestinal symptoms similarly improved. Hypnotherapy resulted in superior improvements on psychological indices with mean change from baseline to 6 months in State Trait Personality Inventory trait anxiety of -4(95% CI -6 to -2) P < 0.0001; -1(-3 to 0.3) P = ns; and 0.3(-2 to 2) P = ns, and in trait depression of -3(-5 to -0.7) P = 0.011; -0.8(-2 to 0.2) P = ns; and 0.6(-2 to 3) P = ns, respectively. Groups improved similarly for QOL (all p ≤ 0.001).

CONCLUSIONS

Durable effects of gut-directed hypnotherapy are similar to those of the low FODMAP diet for relief of gastrointestinal symptoms. Hypnotherapy has superior efficacy to the diet on psychological indices. No additive effects were observed.

Challenges of Quantifying FODMAPs in Enteral Nutrition Formulas: Evaluation of Artifacts and Solutions

BACKGROUND

Diarrhea associated with enteral nutrition has been attributed to excessive FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) content of formulas. This study aimed to readdress their FODMAP content by measuring fermentation-specific effects after a formula load in healthy participants and by defining issues with analytical methods.

METHODS

Breath hydrogen production expressed as mean area under the curve (AUC) for 12 hours after ingestion of 15 g lactulose or 500 mL of 1 of 2 formulas of seemingly different FODMAP content was evaluated in a double crossover design. Quantification of specified FODMAPs via enzymatic and liquid chromatographic assays was assessed with additional controls to investigate the influence of maltodextrin and sucrose present in the formulas, and alternative assays were applied.

RESULTS

In 15 hydrogen-producing participants, AUC following both formulas was minimal (≤21 ppm/12 h) compared with 15 g lactulose ( P < .001). Elevated breath hydrogen was detectable when >2.5 g fructo-oligosaccharide was consumed. Maltodextrin showed dose-dependent interference with enzymatic measurement of fructans and coeluted with raffinose with liquid chromatography. Application of an alternative fructan assay that includes additional enzymes to hydrolyze maltodextrins indicated that fructan content was <15% of that previous reported. Galacto-oligosaccharide (GOS) content could not be estimated by chromatography due to maltodextrins. An enzymatic assay, while overestimating GOS content, showed it to be very low.

CONCLUSION

FODMAPs were not detected in enteral formulas in human bioassays, and their content may be grossly overestimated mainly due to high formula concentrations of maltodextrin. Better estimates of FODMAP content in enteral formulas can be made by alternative assay approaches.

Review article: insights into colonic protein fermentation, its modulation and potential health implications

BACKGROUND

Beneficial effects of carbohydrate fermentation on gastrointestinal health are well established. Conversely, protein fermentation generates harmful metabolites but their relevance to gastrointestinal health is poorly understood.

AIM

To review the effects of increased protein fermentation on biomarkers of colonic health, factors influencing fermentative activity and potential for dietary modulation to minimise detrimental effects.

METHODS

A literature search was performed in PubMed, Medline, EMBASE and Google scholar for clinical and pre-clinical studies using search terms - 'dietary protein', 'fermentation', 'putrefaction', 'phenols', 'sulphide', 'branched-chain fatty acid', 'carbohydrate fermentation', 'gastrointestinal'.

RESULTS

High protein, reduced carbohydrate diets alter the colonic microbiome, favouring a potentially pathogenic and pro-inflammatory microbiota profile, decreased short-chain fatty acid production and increased ammonia, phenols and hydrogen sulphide concentrations. These metabolites largely compromise the colonic epithelium structure, causing mucosal inflammation but may also directly modulate the enteric nervous system and intestinal motility. Increased protein fermentation as a result of a high-protein intake can be attenuated by addition of oligosaccharides, resistant starch and nonstarch polysaccharides and a reduction in total protein or specifically, aromatic and sulphur-containing amino acids. These factors may have clinical importance as novel therapeutic approaches to problems, in which protein fermentation may be implicated, such as malodorous flatus, irritable bowel syndrome, ulcerative colitis and prevention of colorectal cancer.

CONCLUSIONS

The direct clinical relevance of excessive protein fermentation in the pathogenesis of irritable bowel syndrome, malodorous flatus and ulcerative colitis are underexplored. Manipulating dietary carbohydrate and protein intake have potential therapeutic applications in such settings and warrant further clinical studies.