Megan Rossi

Beyond Sodium, Phosphate and Potassium: Potential Dietary Interventions in Kidney Disease

People with kidney disease are advised to restrict individual nutrients, such as sodium, potassium, and phosphate, in line with current best practice guidelines. However, there is limited evidence to support the efficacy of single nutrient strategies, and compliance remains a challenge for clinicians to overcome. Many factors contribute to poor compliance with dietary prescriptions, including conflicting priorities for single nutrient restriction, the arduous self‐monitoring required, and the health‐related knock‐on effects resulting from targeting these nutrients in isolation. This paper reviews the evidence base for the overall pattern of eating as a potential tool to deliver a diet intervention in which all the nutrients and foods work cumulatively and synergistically to improve clinical outcomes. These interventions may assist in kidney disease management and overcome these innate challenges that single nutrient interventions possess. Healthy dietary patterns are typically plant‐based and lower in sodium and animal proteins. These patterns may have numerous mechanistic benefits for cardiovascular health in kidney disease, most notably through the increase in fruit, vegetables, and plant‐based protein, as well as improved gut health through the increase in dietary fiber. The evidence to date on optimal dietary patterns points toward use of a predominantly plant‐based diet, and suggests its adoption may improve clinical outcomes in dialysis patients. However, clinical trials are needed to determine whether these diet interventions are feasible, safe, and effective in this patient population.

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

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

Irritable bowel syndrome and diet: where are we in 2018?

Purpose of review The aim is to review the most recent advances in the evidence supporting the use of various dietary interventions for the management of irritable bowel syndrome (IBS). Recent findings There is insufficient evidence of the effect of fibres other than psyllium in IBS, whereas the recent studies on prebiotics suggest a limited effect in IBS. Recent probiotic trials continue to provide varying results, with some probiotic strains exhibiting beneficial effects, whereas others show no effect. Recent trials have also confirmed the clinical effectiveness of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (i.e. low FODMAP diet) in IBS. Although gluten sensitivity has also been recently investigated, its presence cannot be confirmed yet because of the presence of other potential contributing compounds in wheat. Studies also suggest a potential beneficial effect of peppermint oil, which warrants further research. Summary It is clear that a low FODMAP diet has a beneficial effect in a majority of patients with IBS. Probiotics also have great potential in the management of IBS; however, it is still unclear which strains and doses are the most beneficial. Further research is needed on the effect of different fibres, or combinations of fibres, in IBS.

Volatile Organic Compounds in Feces Associate With Response to Dietary Intervention in Patients With Irritable Bowel Syndrome

Background & Aims Dietary interventions are effective in management of patients with irritable bowel syndrome (IBS), although responses vary. We investigated whether fecal levels of volatile organic compounds (VOCs) associate with response to dietary interventions in patients with IBS. Methods Adults who fulfilled the Rome III criteria for IBS were recruited to a 2x2 factorial randomized controlled trial. Patients were randomly assigned to a group counselled to follow a diet low in fructans, galacto‐oligosaccharides, lactose, fructose, and polyols (low‐FODMAP diet, n = 46) or a group that received placebo dietary advice (sham diet, n = 47) for 4 weeks. Patients from each group were also given either a multi‐strain probiotic or placebo supplement. Response was defined as a reduction of 50 points or more on the validated IBS symptom scoring system. Fecal samples were collected from participants at baseline and end of the 4‐week study period; VOCs were analyzed by a gas‐chromatography sensor device. VOC profiles were determined using a pipeline involving wavelet transformation followed by feature selection based on random forest. A partial least squares classifier was constructed to classify VOC profiles by response and accuracies were determined using 10‐fold cross‐validation. Results Data from 93 patients who completed the study (63 female) were used in the final analysis. More patients responded to the low‐FODMAP diet (37/46, 80%) than the sham diet (21/47, 45%) (P < .001), but there was no difference in response between patients given the probiotic (31/49, 63%) vs the placebo (27/44, 61%) (P = .850), with no interaction between the diet and supplement interventions. At baseline, VOC profiles contained 15 features that classified response to the low‐FODMAP diet with a mean accuracy of 97% (95% CI, 96%–99%) and 10 features that classified response to probiotic with a mean accuracy of 89% (95% CI, 86%–92%). End of treatment models achieved similar predictive powers and accuracies. Conclusion Fecal VOC profiling is a low cost, non‐invasive tool that might be used to predict responses of patients with IBS to low‐FODMAP diet and probiotics and identify their mechanisms of action. ISRCTN registry no: 02275221.

PWE-126 Low fodmap diet effect on IBS gastrointestinal microbiome and metabolites and prediction of response

Introduction Prebiotic β-galactooligosaccharides (B-GOS) may counteract the microbiome modifying effect of the low FODMAP diet (LFD) in patients with irritable bowel syndrome (IBS). Faecal metabolites may predict why only some patients respond to the LFD paving the way towards more personalised treatment. The aim of this randomised controlled trial (RCT) was to investigate: a) the impact of the LFD and LFD+1.4 g/d B-GOS compared to Control on the gut microbiome in IBS, and b) if differences in faecal or urinary metabolites predict response to the LFD. Methods A 3-arm RCT was performed in 69 IBS patients randomised to: Sham diet +Placebo (Control), LFD +Placebo (LFD) or LFD +B GOS. This study investigated global symptom response (adequate relief), gut microbiome (16S rRNA sequencing), short-chain fatty acids (SCFA, gas liquid chromatography), volatile organic compounds (VOC) (gas chromatography/mass spectrometry) and urine metabolomics (NMR spectroscopy) at baseline (BL) and 4 weeks. Data were analysed by Chi2 for dichotomous outcomes and Kruskal-WallisMann-Whitney U tests for continuous variables. Predictive analysis was tested using receiver operator curves (ROC) and orthoganol partial least squared discriminant analysis (OPLS-DA). Results Response rate (adequate relief) at 4 weeks was greater in the LFD+GOS (67%) and LFD (50%) than the Control group (30%) (p=0.046). The phylum Actinobacteria was lower (p<0.001), specifically Bifidobacterium (p=0.002) and Collinsella (p=0.004), in the LFD and LFD+B GOS groups compared to Control at 4 weeks. Prediction of response to the LFD was seen in the LFD group only, with significant separation of BL faecal VOC profiles (AUC=0.854, p=0.045), faecal propionate (AUC=0.848, p=0.009), and urine metabolite profiles (Q2=0.296 vs randomised-0.175). Roseburia, Blautia, Lachnospira and Faecalibacterium, were positively but not significantly associated with VOC classes that predicted response when all samples were correlated. Microbiome and VOC showed a significant negative correlation between propionic acid derivatives and Phascolarctobacterium (r=-0.85 and-0.81, p<0.05) at BL in the LFD group only although the difference in Phascolarctobacterium between responders (1.5%) and non-responders (9.3%) at BL did not reach significance (p=0.055). Conclusions The LFD +B GOS improves symptoms in IBS compared to Control but the LFD significantly reduces Actinobacteria and addition of 1.4 g/d of prebiotic B-GOS does not overcome this effect. Faecal VOCs and SCFAs and urine metabolomes may predict clinical response to the LFD, and specific bacterial groups correlate with predictive metabolites. Larger studies are required to validate these algorithms to develop personalised nutrition in IBS.

OC-026 Prebiotic b-galacto-oligosaccharides in conjunction with the low fodmap diet improves symptoms of irritable bowel syndrome but does not prevent decline of bifidobacteria: a randomised controlled trial

Introduction Dietary restriction of fermentable oligo-, di-, mono -saccharides and polyols (low FODMAP diet, LFD) is widely used for the management of irritable bowel syndrome (IBS), however it reduces gastrointestinal (GI) bifidobacteria. B-galacto-oligosaccharide (B-GOS; HOST-G904) are prebiotics that reduce symptoms and increase bifidobacteria in IBS however the combination of the two therapies has not previously been investigated. Method This randomised controlled trial aimed to investigate whether: 1) IBS symptoms improved on LFD supplemented with B-GOS compared to control; and 2) B-GOS could prevent the reduction of GI bifidobacteria seen in patients following the LFD. Adults fulfilling Rome criteria for IBS were screened (n=130). Sixty-nine patients were recruited to a multicentre 3-arm parallel RCT and were randomised to: control (sham diet/placebo), LFD only (LFD/placebo) or LFD plus B-GOS (LFD/B-GOS) for four weeks. Validated questionnaires were used to assess GI symptoms at week 0 and week 4 and a stool sample collected for analysis at week 0, week 1 and week 4. Stool were analysed for bifidobacteria using fluorescent in situ hybridisation, and short-chain fatty acids (SCFA) and pH were measured using gas chromatography and pH probe respectively. Logistic regression, and ANOVA/ANCOVA (with post-hoc correction) were used to determine differences across the three groups. Results At week 4 adequate relief of IBS symptoms differed significantly between control (30.4%), LFD (50%) and LFD/B-GOS (66.7%) (p=0.046), with post-hoc differences specifically between control and LFD/B-GOS (p=0.015). Individual IBS symptoms were more markedly improved in the LFD/B-GOS group compared to control. Bifidobacteria (log10/g dry weight) also differed across the groups (control 9.8, LFD 9.6, LFD/B-GOS 9.5; p=0.009), with post-hoc differences between the LFD/B-GOS and control at week 4 (p=0.009) Higher stool pH, and lower butyrate at week 1 and week 4 were observed in the LFD vs control diet group. Similar differences were observed in the LFD/B-GOS vs control diet group although pH was not higher than control until week 4. Conclusion Symptoms of IBS markedly improved during LFD supplemented with B-GOS prebiotic, suggesting a synergy between the two therapies. The LFD significantly impacts the GI luminal environment within the first seven days and these changes persist with diet restriction, however addition of a low dose prebiotic does not overcome the effect of diet on bifidobacteria. Disclosure of Interest B. Wilson Conflict with: BW is the recipient of a PhD fellowship awarded by Clasado BioSciences., M. Rossi: None Declared, G. Parkes: None Declared, Q. Aziz: None Declared, S. Anderson: None Declared, P. Irving: None Declared, M. Lomer: None Declared, K. Whelan: None Declared