ORCID Profile
0000-0002-9560-4469
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Publisher: Wiley
Date: 09-09-2022
DOI: 10.1111/APT.17216
Abstract: Accurate definition of the gastroduodenal and ileocaecal junctions (GDJ, ICJ) is essential for the measurement of regional transit times. 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-in idual variance in transit times. Similar analyses were completed with tandemly ingested gas-sensing capsules. 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. Key anatomical landmarks are accurately identified with the gas-sensing capsule in healthy in iduals. Intra-in idual differences in transit times between capsules are probably due to physiological factors. Studies in populations with gastrointestinal diseases are now required.
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.CGH.2021.12.016
Abstract: 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. 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. 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. 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).
Publisher: Wiley
Date: 28-09-2023
DOI: 10.1111/APT.17704
Publisher: Wiley
Date: 30-06-2023
DOI: 10.1111/APT.17629
Abstract: Carbohydrate fermentation plays a pivotal role in maintaining colonic health with excessive proximal and deficient distal fermentation being detrimental. To utilise telemetric gas‐ and pH‐sensing capsule technologies for defining patterns of regional fermentation following dietary manipulations, alongside conventional techniques of measuring fermentation. 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. 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. 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.
Publisher: Cambridge University Press (CUP)
Date: 08-10-2020
DOI: 10.1017/S0007114520003943
Abstract: The therapeutic value of specific fibres is partly dependent on their fermentation characteristics. Some fibres are rapidly degraded with the generation of gases that induce symptoms in patients with irritable bowel syndrome (IBS), while more slowly or non-fermentable fibres may be more suitable. More work is needed to profile a comprehensive range of fibres to determine suitability for IBS. Using a rapid in vitro fermentation model, gas production and metabolite profiles of a range of established and novel fibres were compared. Fibre substrates ( n 15) were added to faecal slurries from three healthy donors for 4 h with gas production measured using real-time headspace s ling. Concentrations of SCFA and ammonia were analysed using GC and enzymatic assay, respectively. Gas production followed three patterns: rapid (≥60 ml/g over 4 h) for fructans, carrot fibre and maize-derived xylo-oligosaccharide (XOS) mild (30–60 ml/g) for partially hydrolysed guar gum, almond shell-derived XOS and one type of high-amylose resistant starch 2 (RS2) and minimal (no differences with blank controls) for methylcellulose, another high-amylose RS2, acetylated or butyrylated RS2, RS4, acacia gum and sugarcane bagasse. Gas production correlated positively with total SCFA ( r 0·80, P 0·001) and negatively with ammonia concentrations ( r –0·68, P 0·001). Proportions of specific SCFA varied: fermentation of carrot fibre, XOS and acetylated RS2 favoured acetate, while fructans favoured butyrate. Gas production and metabolite profiles differed between fibre types and within fibre classes over a physiologically relevant 4-h time course. Several fibres resisted rapid fermentation and may be candidates for clinical trials in IBS patients.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Cambridge University Press (CUP)
Date: 2022
DOI: 10.1017/JNS.2022.9
Abstract: 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.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-01-2023
Publisher: Elsevier BV
Date: 12-2021
Publisher: Wiley
Date: 19-01-2020
Publisher: Wiley
Date: 18-01-2022
DOI: 10.1111/JGH.15772
Abstract: 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. Published literature and clinical experience were reviewed. 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. 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.
Publisher: Informa UK Limited
Date: 12-05-2020
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1093/AJCN/NQAC176
Publisher: BMJ
Date: 20-08-2021
DOI: 10.1136/GUTJNL-2021-324891
Abstract: 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, in idual 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 in idual, will be the future for personalising fibre therapy for enhancing the personalised management of patients with IBS.
Publisher: Cold Spring Harbor Laboratory
Date: 18-11-2022
DOI: 10.1101/2022.11.17.516695
Abstract: Dietary fibre regulates blood pressure (BP) through gut microbial production of acidic metabolites known as short-chain fatty acids (SCFAs). The specific mechanisms of how SCFAs regulate BP are still emerging. We hypothesised that acidic metabolites that are abundant in the large intestine may activate proton-sensing G-protein coupled receptors, such as GPR65, thus conferring BP regulating effects. Using mouse models, we found that dietary fibre levels determined the luminal pH in the large intestine, through production of SCFAs by the gut microbiota. We then investigated a new mouse model lacking GPR65, which spontaneously developed higher BP, cardiac and renal hypertrophy and fibrosis. We identified that low pH, acting via GPR65 signalling, increased cAMP production and phosphorylation of CREB, and regulated inflammatory cytokine production involved in hypertension. We showed that the benefits of diets high in fibre, which usually prevent hypertension and its associated phenotypes, were decreased in mice lacking GPR65. Finally, we provided proof-of-concept evidence that the luminal pH profile in the colon of hypertensive participants is higher than that of normotensive participants. Colonic pH was further associated with dietary fibre, particularly in the colonic regions where fibre is fermented by the gut microbiota. Together, we show that pH sensing by GPR65 underlies at least some of the cardiovascular benefits of dietary fibre.
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1093/AJCN/NQY041
Abstract: Dysfunction of the gut microbiota is frequently reported as a manifestation of chronic diseases, and therefore presents as a modifiable risk factor in their development. Diet is a major regulator of the gut microbiota, and certain types of dietary fiber may modify bacterial numbers and metabolism, including short-chain fatty acid (SCFA) generation. A systematic review and meta-analysis were undertaken to assess the effect of dietary fiber interventions on gut microbiota composition in healthy adults. A systematic search was conducted across MEDLINE, EMBASE, CENTRAL, and CINAHL for randomized controlled trials using culture and/or molecular microbiological techniques evaluating the effect of fiber intervention on gut microbiota composition in healthy adults. Meta-analyses via a random-effects model were performed on alpha ersity, prespecified bacterial abundances including Bifidobacterium and Lactobacillus spp., and fecal SCFA concentrations comparing dietary fiber interventions with placebo/low-fiber comparators. A total of 64 studies involving 2099 participants were included. Dietary fiber intervention resulted in higher abundance of Bifidobacterium spp. (standardized mean difference (SMD): 0.64 95% CI: 0.42, 0.86 P < 0.00001) and Lactobacillus spp. (SMD: 0.22 0.03, 0.41 P = 0.02) as well as fecal butyrate concentration (SMD: 0.24 0.00, 0.47 P = 0.05) compared with placebo/low-fiber comparators. Subgroup analysis revealed that fructans and galacto-oligosaccharides led to significantly greater abundance of both Bifidobacterium spp. and Lactobacillus spp. compared with comparators (P < 0.00001 and P = 0.002, respectively). No differences in effect were found between fiber intervention and comparators for α- ersity, abundances of other prespecified bacteria, or other SCFA concentrations. Dietary fiber intervention, particularly involving fructans and galacto-oligosaccharides, leads to higher fecal abundance of Bifidobacterium and Lactobacillus spp. but does not affect α- ersity. Further research is required to better understand the role of in idual fiber types on the growth of microbes and the overall gut microbial community. This review was registered at PROSPERO as CRD42016053101.
Publisher: Elsevier BV
Date: 05-2021
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Daniel So.