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.

Practical application of the Crohn's disease exclusion diet as therapy in an adult Australian population.

There is demand from patients and clinicians to use the Crohn's disease exclusion diet (CDED) with or without partial enteral nutrition (PEN). However, the therapeutic efficacy and nutritional adequacy of this therapy are rudimentary in an adult population. This review examines the evidence for the CDED in adults with active luminal Crohn's disease and aims to provide practical guidance on the use of the CDED in Australian adults. A working group of nine inflammatory bowel disease (IBD) dietitians of DECCAN (Dietitians Crohn's and Colitis Australian Network) and an IBD gastroenterologist was established. A literature review was undertaken to examine (1) clinical indications, (2) monitoring, (3) dietary adequacy, (4) guidance for remission phase, and (5) diet reintroduction after therapy. Each diet phase was compared with Australian reference ranges for food groups and micronutrients. CDED with PEN is nutritionally adequate for adults containing sufficient energy and protein and meeting > 80% of the recommended daily intake of key micronutrients. An optimal care pathway for the clinical use of the CDED in an adult population was developed with accompanying consensus statements, clinician toolkit, and patient education brochure. Recommendations for weaning from the CDED to the Australian dietary guidelines were developed. The CDED + PEN provides an alternate partial food-based therapy for remission induction of active luminal Crohn's disease in an adult population. The CDED + PEN should be prioritized over CDED alone and prescribed by a specialist IBD dietitian. DECCAN cautions against using the maintenance diet beyond 12 weeks until further evidence becomes available.

Perceived dietary intolerances, habitual intake and diet quality of patients with an ileoanal pouch: Associations with pouch phenotype (and behaviour).

BACKGROUND AND AIMS: Ileoanal pouch patients frequently attribute pouch-related symptoms and pouchitis with diet. We aimed to assess perceived food intolerance and habitual dietary intake and their relationship with pouch indication, symptoms and current or history of pouchitis. METHODS: In this cross-sectional study, patients with an ileoanal pouch completed a dietary intolerance and a food frequency questionnaire, that specifically quantifies habitual intake of FODMAPs. Perceived dietary intolerance rates, nutrient intake and diet quality, and their differences based on pouch indication, symptom, and current or history of pouchitis were assessed. Associations between intolerances and intake, and between dietary intake with pouchitis risk were analysed using univariable and multivariable regression analysis. RESULTS: Of the 58 (10 FAP and 48 UC) patients with complete data, 81% of UC and 80% of FAP patients reported dietary intolerances. Overall diet quality was good. Differences in dietary intake were limited to a few food groups. Patients with a history of pouchitis had a lower intake of fruits (p = 0.03) and nuts (p = 0.004). Patients with current pouchitis had a lower intake of nuts (p = 0.02). On multivariable logistic regression, intake of dietary fibre was associated negatively [OR 0.68(95%CI:0.51-0.92)] and of non-digestible oligosaccharides positively with pouchitis history [OR 5.5(95% CI:1.04-29.1)]. CONCLUSIONS: In patients with an ileoanal pouch, perceived dietary intolerances are common but had minimal impact on nutritional adequacy and diet quality. Negative associations of the intakes of fruits, nuts and dietary fibre and positive association with non-digestible oligosaccharides with a history of pouchitis require further study to inform dietary recommendations.

Association between dietary factors, symptoms, and psychological factors in adults with dyspepsia: A cross-sectional study.

BACKGROUND: Evidence-based dietary management approaches for symptoms of dyspepsia are lacking. This study aimed to compare dietary factors, symptoms, quality of life (QOL) and salivary cortisol in dyspepsia participants and healthy controls. METHODS: A cross-sectional survey was completed by adults with dyspepsia (n = 121) meeting Rome IV criteria and healthy controls (n = 52). Outcome measures included self-reported questionnaires about dietary habits, triggers, restrictions, dietary management approaches, nutritional intake, psychological variables, QOL, gastrointestinal symptoms, and optional cortisol awakening response (CAR) via saliva samples. Data were analyzed using Chi-square or Mann-Whitney U. Cortisol awakening response data was analyzed using moderated regression controlling for age, gender and distress. KEY RESULTS: Fermentable carbohydrates (FODMAPs) (55%) were the most reported trigger in adults with dyspepsia. The dyspepsia group (88%) followed special diets more than controls (47%; p < 0.001), with a low FODMAP diet being most common (69%). The dyspepsia group consumed less fiber (p = 0.014), calcium (p = 0.015), and total FODMAPs (p < 0.001) than controls. There was a greater prevalence of comorbid anxiety (41%) and depression (31%) in dyspepsia compared to controls (15% and 12%, respectively, p < 0.001 and p = 0.006). The dyspepsia group had poorer QOL and greater gastrointestinal symptom severity than controls (p < 0.001). There was a negative association between anxiety and CAR (p = 0.001) in dyspepsia but not in controls. CONCLUSIONS & INFERENCES: Adults with dyspepsia follow special diets more than controls and perceive FODMAPs as a key dietary trigger. These findings highlight the importance of monitoring nutritional adequacy and QOL, and emphasize mechanisms of depleted stress response in dyspepsia, warranting further exploration.

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.

Gaseous metabolites as therapeutic targets in ulcerative colitis.

Diet therapies are currently under-utilised in optimising clinical outcomes for patients with active ulcerative colitis (UC). Furthermore, existing dietary therapies are framed by poorly defined mechanistic targets to warrant its success. There is good evidence to suggest that microbial production of gaseous metabolites, hydrogen sulfide (H2S) and nitric oxide (NO) are implicated in the development of mucosal inflammation in UC. On a cellular level, exposure of the colonic epithelium to excessive concentrations of these gases are shown to promote functional defects described in UC. Hence, targeting bacterial production of these gases could provide an opportunity to formulate new dietary therapies in UC. Despite the paucity of evidence, there is epidemiological and clinical data to support the concept of reducing mucosal inflammation in UC via dietary strategies that reduce H2S. Several dietary components, namely sulphur-containing amino acids and inorganic sulphur have been shown to be influential in enhancing colonic H2S production. More recent data suggests increasing the supply of readily fermentable fibre as an effective strategy for H2S reduction. Conversely, very little is known regarding how diet alters microbial production of NO. Hence, the current evidence suggest that a whole diet approach is needed. Finally, biomarkers for assessing changes in microbial gaseous metabolites in response to dietary interventions are very much required. In conclusion, this review identifies a great need for high quality randomised-controlled trials to demonstrate the efficacy of a sulphide-reducing dietary therapy for patients with active UC.

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).

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.

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.

Evaluating tolerability of resistant starch 2, alone and in combination with minimally fermented fibre for patients with irritable bowel syndrome: a pilot randomised controlled cross-over trial.

Resistant starch 2 (RS2) may offer therapeutic value to irritable bowel syndrome (IBS) patients particularly in combination with minimally fermented fibre, but tolerability data are lacking. The present study evaluated the tolerability of RS2, sugarcane bagasse and their combination in IBS patients and healthy controls. Following baseline, participants consumed the fibres in escalating doses lasting 3 d each: RS2 (10, 15 and 20 g/d); sugarcane bagasse (5, 10 and 15 g/d); and their combination (20, 25 and 30 g/d). Gastrointestinal symptoms were assessed daily. Six IBS patients and five controls were recruited. No differences in overall symptoms from baseline were found across the fibre doses (IBS, P = 0⋅586; controls, P = 0⋅687). For IBS patients, all RS2 doses led to increased bloating. One IBS patient did not tolerate the low combination dose and another the high sugarcane bagasse dose. Supplementation of RS2 ≤ 20 g/d caused mild symptoms and was generally tolerated in IBS patients even when combined with minimally fermented fibre.

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.

Food-related quality of life in adults with inflammatory bowel disease is associated with restrictive eating behaviour, disease activity and surgery: A prospective multicentre observational study.

BACKGROUND: Measuring food-related quality of life (FRQoL) quantifies the psychosocial impact of eating and drinking. FRQoL and associated factors are not well explored in people with inflammatory bowel disease (IBD), despite IBD being a chronic disease affecting the digestive tract. The present study aimed to characterise and identify any patient or disease-related predictors of FRQoL in individuals with IBD. METHODS: Adults with a formal diagnosis of IBD were recruited to a prospective multicentre cross-sectional study between April 2018 and December 2019. Participants completed questionnaires measuring FRQoL (FRQoL-29), clinical disease activity (Harvey Bradshaw Index and Simple Clinical Colitis Activity Index), restrictive eating behaviour (Nine-Item Avoidant/Restrictive Food Intake Disorder Screen), mental health (Depression Anxiety Stress Scale-21) and other patient and disease-related variables. A multivariable regression was performed to identify factors associated with FRQoL. RESULTS: One hundred and eight participants completed the questionnaires (n = 39, Crohn's disease; n = 69, ulcerative colitis). The mean FRQoL was 79 (95% confidence interval = 75-84) (poor, 0; superior, 145). Poorer FRQoL was observed in those with restrictive eating behaviour associated with fear of a negative consequence from eating (p < 0.0001) and reduced appetite (p < 0.030). Greater FRQoL was observed in those with lower disease activity (p < 0.0001) and previous IBD surgery (p = 0.024). FRQoL was not associated either way by IBD phenotype, duration, or gender. The majority of participants obtained their dietary information from the internet (60%) or gastroenterologist (46%). CONCLUSIONS: FRQoL in people with IBD is poorer in those with restrictive eating behaviours and clinically active disease. Interestingly, it was greater in those with previous IBD surgery. Further research is required to validate these associations and explore longitudinal effects of poor FRQoL on patient outcomes and potential strategies for prevention or management of impaired FRQoL in IBD.

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).

Fecal microbiota transplantation augmented by a sulfide-reducing diet for refractory ulcerative colitis: A case report with functional metagenomic analysis.

Fecal microbiota transplantation (FMT) is effective for induction of remission in ulcerative colitis (UC). Diet has potential to augment the efficacy and durability of FMT by encouraging engraftment of transplanted microorganisms. A trial of FMT combined with a defined diet was undertaken as salvage therapy for a 71-year-old woman with active steroid-refractory extensive UC. A multidimensional sulfide-reducing diet (4-SURE diet) was commenced followed by single-donor FMT administered by colonoscopy and then enemas over 7 days. Dietary adherence, clinical evaluation, and stool samples for metagenomic profiling were undertaken at weeks 0, 4, 8, and 24. Colonoscopy was performed 8 weeks post-FMT. Shotgun metagenomic profiling of the donor fecal suspension was also performed. A rapid clinical response to FMT and 4-SURE diet was observed with normalization of stool frequency (≤2 motions/day) and resolution of rectal bleeding within 2 weeks. Dietary adherence was excellent. Colonoscopy at week 8 revealed no evidence of active colitis (Mayo endoscopic sub-score 0) with histology showing no evidence of acute or chronic lamina propria inflammatory cell infiltrate. Sustained clinical and endoscopic remission out to 24 weeks was observed. Metagenomic sequencing confirmed sustained engraftment of beneficial donor microbiota with increased alpha-diversity and capacity for short-chain fatty acid production, including Faecalibacterium prauznitzii and Eubacterium hallii. This case report supports the rationale of prescribed diet therapy to support engraftment of donor microbiota following FMT for UC. Further large trials with a diet-arm control group are needed to evaluate FMT augmented by a defined diet in UC.

Food avoidance, restrictive eating behaviour and association with quality of life in adults with inflammatory bowel disease: A systematic scoping review.

BACKGROUND: Dietary misconceptions and behaviours may worsen outcomes of inflammatory bowel disease (IBD). This scoping review aims to examine the dietary beliefs and behaviours of individuals with IBD and identify evidence of food avoidance, dietary restriction or disordered eating and any association with quality of life (QoL). METHODOLOGY: A systematic search of CINAL, EMBASE, MEDLINE was conducted. Primary, peer-reviewed studies in English examining dietary beliefs and dietary behaviours or diet and quality of life in adults with inflammatory bowel disease were included. Key dietary terminology was pre-defined. RESULTS: Twenty-nine studies met inclusion criteria. A range of quantitative self-reported questionnaires (16/29), qualitative interviews (1/29) and mixed methods (7/29) were used to measure dietary beliefs and dietary behaviours. A high prevalence of food avoidance (28-89%) and restrictive dietary behaviours (41-93%) were identified. Factors associated with these behaviours included a diagnosis of CD, perceived active disease, female sex, dietary misinformation, and fears of adverse bowel symptoms. Diet and QoL remains largely unexplored in IBD beyond two recent studies demonstrating impairment of food-related quality of life in IBD. CONCLUSION: A high prevalence of self-reported food avoidance and restrictive dietary behaviour exists in people with IBD. The psychosocial impact of IBD-related dietary behaviour is poorly understood. Validated tools with predefined diet terminology and objective markers of disease activity are required to measure dietary behaviour in future prospective studies, using food-related quality of life as an outcome measure.

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.

The Adequacy of Habitual Dietary Fiber Intake in Individuals With Inflammatory Bowel Disease: A Systematic Review.

BACKGROUND: Dietary fiber may influence disease course in individuals with inflammatory bowel disease (IBD), yet there is a paucity of understanding of habitual fiber intakes. OBJECTIVES: To identify studies measuring fiber intakes of individuals with IBD, compare the adequacy of fiber intakes with that of control groups or respective national dietary guidelines, and examine factors associated with fiber consumption. METHODS: Five electronic databases-MEDLINE, CINAHL, SCOPUS, PROQUEST, and COCHRANE LIBRARY-were systematically searched, using search terms inflammatory bowel disease, Crohn's disease, ulcerative colitis, dietary intake, and fiber, until December 2019, with hand searching of reference lists. Primary studies were included if fiber intakes were measured in participants 18 years of age or older, with confirmed IBD, with or without comparison to a control. RESULTS: A total of 2105 publications were identified, and 26 met inclusion criteria. Total fiber intake of 4164 participants with IBD ranged broadly (9.9 ± 7.8 g/day to 21.0 ± 10.5 g/day). Most (18/26) used cross-sectional study design, with a large degree of heterogeneity in tools measuring fiber intake. Sixty-six percent of studies comparing participants with IBD with control groups found that participants with IBD consumed significantly less fiber than control subjects. Four studies reported that less than 10% to 21% of IBD participants met their national fiber recommendations. Data conflicted regarding an association between disease type, disease activity, or rate of relapse and fiber intake. CONCLUSIONS: Individuals with IBD consume less fiber than healthy populations. Fiber intakes are inadequate compared with respective national fiber guidelines. Interpretation of factors associated with fiber intakes were limited by data quality and conflicting results. Future research is required into factors associated with fiber intake and whether increasing fiber intakes can influence disease course and behavior.