The clinical value of breath hydrogen testing

The Role of Fermentable Fibre on Endurance Exercise Capacity: A Randomised Crossover Trial of Inulin Supplementation

Manipulation of the mouse gut microbiome has been shown to increase gut-derived short-chain fatty acids and improve exercise capacity. Associations between exercise performance and gut microbiome composition and metabolites have also been identified in human studies. Yet there is little direct evidence that prebiotics are able to increase acetate production and improve exercise capacity in human participants. We conducted a randomised controlled cross-over trial with 21 healthy and active males (35.0 ± 6.9 years; 24.4 ± 2.7 kg/m2) to investigate the effect of 15 g of inulin (prebiotic) on exercise performance (15 km cycle time trial), compared to placebo. Time to completion of a 15 km time trial was the primary outcome, while plasma acetate concentration and markers of inulin fermentation (breath H2 concentration) and muscle oxygenation were measured to explore potential mechanisms of action. Time to complete the 15 km time trial was not affected by inulin mean difference between inulin and placebo trials: (-10.37 s, 95% CI [-150.8, 130.1 s], p = 0.884). The marker of inulin fermentation (H2 concentration increase from baseline) was significantly higher in inulin compared to placebo condition (+42.61 ppm, 95% CI [30.04, 55.19], p = 0.001 and +31.13 ppm, 95% CI [3.73, 58.51], p = 0.029, respectively), but plasma acetate concentration did not differ between conditions. Likewise, markers of muscle oxygenation were not different between inulin and placebo. Our current results do not support the acute use of prebiotics to improve exercise performance in adults. Possible explanations for the absence of ergogenic effects may be that the timing between prebiotic ingestion and exercise was too short to allow for complete fermentation into acetate, participants were in a fasted rather than a fed state, or that the single dose of supplement was insufficient. These factors, together with advanced methods (stable isotope studies) should be investigated in a follow-up study to elucidate the fate and role of colonic-derived acetate during exercise.

Management of abdominal bloating and distension, from subjective to objective

Abdominal distension is a clinical occurrence that involves a measurable, objective increase in abdominal circumference, which patients report as feeling like pregnant or like having a balloon inside the abdomen. This sign is often preceded by a subjective feeling of abdominal heaviness or bloating, reported as the sensation of having a huge amount of gas trapped inside. These manifestations are highly prevalent and may reflect on their own a gut-brain axis condition, such as functional abdominal distension, or be part of other disorders such as functional dyspepsia or irritable bowel syndrome (IBS). The prevalence of abdominal distension and bloating is 3.5 %. However, when associated with other gut-brain axis disorders such as dyspepsia or IBS, prevalence grows above 50 %. The etiology and pathophysiology of abdominal bloating and distension are highly complex and represent a challenge for both the practitioner and the patient. The patient often associates these sensations with trapped gas, and attributes them to some food intolerance, hence he/she adopts a highly restrictive diet that fails to resolve distension while incurring the risk of nutritional deficiencies or secondary dysbiosis, making a directed treatment guideline necessary.

Diagnosing and managing irritable bowel syndrome with predominant diarrhoea in clinical practice: online survey among gastroenterologists and general practitioners

Introduction

Irritable bowel syndrome (IBS) represents the most common disorder of gut-brain interaction encountered in clinical practice. The Rome IV criteria define the disorder. Over the years, many guidelines proposed guidance during the diagnostic and therapeutic approach of patients with presumed IBS.

Aim

This study investigates the management of IBS with predominant diarrhoea (IBS-D) by Belgian gastroenterologists (GE) and general practitioners (GP) in daily practice.

Methods

An online vignette-based survey was conducted exploring the diagnostic and therapeutic approach of patients suffering from IBS with predominant diarrhoea (IBS-D) in primary and secondary care.

Results

64 GE and 31 GP completed the survey. Abdominal pain and discomfort led to an IBS diagnosis in 88% and 84% of cases, respectively. The diagnosis rate dropped to 58.3% with diarrhoea as main presentation and 26.8% for patients aged 65. Additional tests were ordered by 89.5% of physicians, including biochemistry (77.9%), stool culture and parasites (59.3%), iFOBT (60.5%), breath testing (17.4%), imaging (12.8%), and endoscopy (9.3%). Upon normal results, 57% of physicians did not order further investigations. Both GP and GE preferred spasmolytics (64.3%) and dietary interventions (23.9%) as first-line treatment for IBS. Second-line treatment options included referral to a specialist or colleague (19.4%), dietary intervention (22.6%), neuromodulators (19.4%), and spasmolytics (14.5%). No GP initiated neuromodulators.

Conclusion

In Belgium, abdominal pain or discomfort are equivalent cardinal symptoms when diagnosing IBS. During the further diagnostic and therapeutic approach most physicians order only limited additional non-invasive testing. Spasmolytics and dietary interventions are favoured in first-line. Upon failure, only GE prescribe neuromodulators, while GP opt for referral. These findings are consistent with the general principles and recommendations outlined in the recently published Belgian guideline for IBS.

The Role of Small Intestinal Bacterial Overgrowth in Obesity and Its Related Diseases

Obesity has become a major public health problem worldwide and its occurrence is increasing globally. Obesity has also been shown to be involved in the occurrence and development of many diseases and pathological conditions, such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus (T2DM), insulin resistance (IR). In recent years, gut microbiota has received extensive attention as an important regulatory part involved in host diseases and health status. A growing body of evidence suggests that gut microbiota dysbiosis has a significant adverse effect on the host. Small intestinal bacterial overgrowth (SIBO), a type of intestinal microbial dysbiosis, has been gradually revealed to be associated with obesity and its related diseases. The presence of SIBO may lead to the destruction of intestinal barrier integrity, increased intestinal permeability, increased endotoxin levels, activation of inflammatory responses, and translocation of bacteria from the colon to the small intestine. However, the causal relationship between SIBO and obesity and the specific mechanisms have not been well elucidated. This review discusses the cross-talk between SIBO and obesity and its related diseases, and expounds its potential mechanisms and interventions, which may help to discover new therapeutic targets for obesity and its related diseases and develop treatment options.

Hydrogen Availability Is Dependent on the Actions of Both Hydrogen-Producing and Hydrogen-Consuming Microbes

Hydrogen gas (H2) is produced by H2-producing microbes in the gut during polysaccharide fermentation. Gut microbiome also includes H2-consuming microbes utilizing H2 for metabolism: methanogens producing methane, CH4, and sulfate-reducing bacteria producing hydrogen sulfide, H2S. H2S is not measured in the evaluation of gaseous byproducts of microbial fermentation. We hypothesize that the availability of measured H2 depends on both hydrogen producers and hydrogen consumers by measuring H2 in vitro and in vivo. In the in vitro study, groups were Bacteroides thetaiotaomicron (B. theta, H2 producers), Desulfovibrio vulgaris (D. vulgaris, H2 consumers), and D. vulgaris + B. theta combined. Gas samples were collected at 2 h and 24 h after incubation and assayed for H2, CH4, and H2S. In the in vivo study Sprague-Dawley rats were gavaged with suspended bacteria in four groups: B. theta, D. vulgaris, combined, and control. Gas was analyzed for H2 at 60 min. In the in vitro experiment, H2 concentration was higher in the combined group (188 ± 93.3 ppm) compared with D. vulgaris (27.17 ± 9.6 ppm) and B. theta groups (34.2 ± 29.8 ppm; P < 0.05); H2S concentration was statistically higher in the combined group (10.32 ± 1.5 ppm) compared with B. theta (0.19 ± 0.03 ppm) and D. vulgaris group (3.46 ± 0.28 ppm; P < 0.05). In the in vivo study, H2 concentrations were significantly higher in the B. theta group (44.3 ± 6.0 ppm) compared with control (31.8 ± 4.3) and the combined group (34.2 ± 8.7, P < 0.05). This study shows that sulfate-reducing bacteria could convert available H2 to H2S, leading to measured hydrogen levels that are dependent on the actions of both H2 producers and H2 consumers.

Assessment of Exercise-Associated Gastrointestinal Perturbations in Research and Practical Settings: Methodological Concerns and Recommendations for Best Practice

Strenuous exercise is synonymous with disturbing gastrointestinal integrity and function, subsequently prompting systemic immune responses and exercise-associated gastrointestinal symptoms, a condition established as "exercise-induced gastrointestinal syndrome." When exercise stress and aligned exacerbation factors (i.e., extrinsic and intrinsic) are of substantial magnitude, these exercise-associated gastrointestinal perturbations can cause performance decrements and health implications of clinical significance. This potentially explains the exponential growth in exploratory, mechanistic, and interventional research in exercise gastroenterology to understand, accurately measure and interpret, and prevent or attenuate the performance debilitating and health consequences of exercise-induced gastrointestinal syndrome. Considering the recent advancement in exercise gastroenterology research, it has been highlighted that published literature in the area is consistently affected by substantial experimental limitations that may affect the accuracy of translating study outcomes into practical application/s and/or design of future research. This perspective methodological review attempts to highlight these concerns and provides guidance to improve the validity, reliability, and robustness of the next generation of exercise gastroenterology research. These methodological concerns include participant screening and description, exertional and exertional heat stress load, dietary control, hydration status, food and fluid provisions, circadian variation, biological sex differences, comprehensive assessment of established markers of exercise-induced gastrointestinal syndrome, validity of gastrointestinal symptoms assessment tool, and data reporting and presentation. Standardized experimental procedures are needed for the accurate interpretation of research findings, avoiding misinterpreted (e.g., pathological relevance of response magnitude) and overstated conclusions (e.g., clinical and practical relevance of intervention research outcomes), which will support more accurate translation into safe practice guidelines.

Immune responses in the irritable bowel syndromes: time to consider the small intestine

BACKGROUND

Irritable bowel syndrome (IBS) is considered a disorder of gut-brain interaction (DGBI), presenting as chronic abdominal pain and altered defaecation. Symptoms are often food related. Much work in the field has focused on identifying physiological, immune and microbial abnormalities in the colon of patients; however, evidence of small intestinal immune activation and microbial imbalance has been reported in small studies. The significance of such findings has been largely underappreciated despite a growing body of work implicating small intestinal homeostatic imbalance in the pathogenesis of DGBIs.

MAIN TEXT

Small intestinal mechanosensation is a characteristic feature of IBS. Furthermore, altered small intestinal barrier functions have been demonstrated in IBS patients with the diarrhoea-predominant subtype. Small intestinal bacterial overgrowth and increased populations of small intestinal mast cells are frequently associated with IBS, implicating microbial imbalance and low-grade inflammation in the pathogenesis of IBS. Furthermore, reports of localised food hypersensitivity responses in IBS patients implicate the small intestine as the site of immune-microbial-food interactions.

CONCLUSIONS

Given the association of IBS symptoms with food intake in a large proportion of patients and the emerging evidence of immune activation in these patients, the current literature suggests the pathogenesis of IBS is not limited to the colon but rather may involve dysfunction of the entire intestinal tract. It remains unclear if regional variation in IBS pathology explains the various symptom phenotypes and further work should consider the intestinal tract as a whole to answer this question.

What Are the Pearls and Pitfalls of the Dietary Management for Chronic Diarrhoea?

Chronic diarrhoea affects up to 14% of adults, it impacts on quality of life and its cause can be variable. Patients with chronic diarrhoea are presented with a plethora of dietary recommendations, often sought from the internet or provided by those who are untrained or inexperienced. In this review, we summarise the possible causes of chronic diarrhoea that can be managed by diet, the symptom improvement and quality of life benefits but also the potential risks of such dietary treatments. Clinicians need to consider both the benefits and risks of dietary treatments before making dietary recommendations to manage chronic diarrhoea. The pivotal role that dietitians have in ensuring optimal symptom improvement without jeopardising nutritional and overall health is discussed.

Intestinal bacterial overgrowth in the early stage of severe acute pancreatitis is associated with acute respiratory distress syndrome

BACKGROUND

In the early stage of acute pancreatitis (AP), a large number of cytokines induced by local pancreatic inflammation seriously damage the intestinal barrier function, and intestinal bacteria and endotoxins enter the blood, causing inflammatory storm, resulting in multiple organ failure, infectious complications, and other disorders, eventually leading to death. Intestinal failure occurs early in the course of AP, accelerating its development. As an alternative method to detect small intestinal bacterial overgrowth, the hydrogen breath test is safe, noninvasive, and convenient, reflecting the number of intestinal bacteria in AP indirectly. This study aimed to investigate the changes in intestinal bacteria measured using the hydrogen breath test in the early stage of AP to clarify the relationship between intestinal bacteria and acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Early clinical intervention and maintenance of intestinal barrier function would be highly beneficial in controlling the development of severe acute pancreatitis (SAP).

AIM

To analyze the relationship between intestinal bacteria change and ALI/ARDS in the early stage of SAP.

METHODS

A total of 149 patients with AP admitted to the intensive care unit of the Digestive Department, Xuanwu Hospital, Capital Medical University from 2016 to 2019 were finally enrolled, following compliance with the inclusion and exclusion criteria. The results of the hydrogen breath test within 1 wk of admission were collected, and the hydrogen production rates at admission, 72 h, and 96 h were calculated. The higher the hydrogen production rates the more bacteria in the small intestine. First, according to the improved Marshall scoring system in the 2012 Atlanta Consensus on New Standards for Classification of Acute Pancreatitis, 66 patients with a PaO2/FiO2 score ≤ 1 were included in the mild AP (MAP) group, 18 patients with a PaO2/FiO2 score ≥ 2 and duration < 48 h were included in the moderately SAP (MSAP) group, and 65 patients with a PaO2/FiO2 score ≥ 2 and duration > 48 h were included in the SAP group, to analyze the correlation between intestinal bacterial overgrowth and organ failure in AP. Second, ALI (PaO2/FiO2 = 2) and ARDS (PaO2/FiO2 > 2) were defined according to the simplified diagnostic criteria proposed by the 1994 European Union Conference. The MSAP group was divided into two groups according to the PaO2/FiO2 score: 15 patients with PaO2/FiO2 score = 2 were included in group A, and three patients with score > 2 were included in group B. Similarly, the SAP group was divided into two groups: 28 patients with score = 2 were included in group C, and 37 patients with score > 2 were included in group D, to analyze the correlation between intestinal bacterial overgrowth and ALI/ARDS in AP.

RESULTS

A total of 149 patients were included: 66 patients in the MAP group, of whom 53 patients were male (80.3%) and 13 patients were female (19.7%); 18 patients in the MSAP group, of whom 13 patients were male (72.2%) and 5 patients were female (27.8%); 65 patients in the SAP group, of whom 48 patients were male (73.8%) and 17 patients were female (26.2%). There was no significant difference in interleukin-6 and procalcitonin among the MAP, MSAP, and SAP groups (P = 0.445 and P = 0.399, respectively). There was no significant difference in the growth of intestinal bacteria among the MAP, MSAP, and SAP groups (P = 0.649). There was no significant difference in the growth of small intestinal bacteria between group A and group B (P = 0.353). There was a significant difference in the growth of small intestinal bacteria between group C and group D (P = 0.038).

CONCLUSION

Intestinal bacterial overgrowth in the early stage of SAP is correlated with ARDS.

Tandem Quantification of Multiple Carbohydrates in Saliva Using Surface-Enhanced Raman Spectroscopy

The detection of carbohydrates in human body fluids is critical for disease diagnosis and healthy monitoring. Despite recent advances in glucose sensing, multiplex detection of different carbohydrates within a single assay that is capable of efficiently providing richer health information remains challenging. Herein, we report a versatile surface-enhanced Raman spectroscopy-based platform for the quantitative detection of monosaccharides (glucose, fructose, and galactose) in one test using a displace-and-trap mechanism. Moreover, due to the use of multiple optical interference-free (1800-2200 cm^-1) signal-independent Raman probes, the detection range of this platform (0.125-7 mg/dL) perfectly covers physiological concentrations, enabling the quantitative detection of glucose and galactose in clinical human saliva samples. This work provides a noninvasive and high-efficiency potential tool for the screening of clinical diabetes and other carbohydrate-related diseases.

Methane and fatty acid metabolism pathways are predictive of Low-FODMAP diet efficacy for patients with irritable bowel syndrome

OBJECTIVE

Identification of microbiota-based biomarkers as predictors of low-FODMAP diet response and design of a diet recommendation strategy for IBS patients.

DESIGN

We created a compendium of gut microbiome and disease severity data before and after a low-FODMAP diet treatment from published studies followed by unified data processing, statistical analysis and predictive modeling. We employed data-driven methods that solely rely on the compendium data, as well as hypothesis-driven methods that focus on methane and short chain fatty acid (SCFA) metabolism pathways that were implicated in the disease etiology.

RESULTS

The patient's response to a low-FODMAP diet was predictable using their pre-diet fecal samples with F1 accuracy scores of 0.750 and 0.875 achieved through data-driven and hypothesis-driven predictors, respectively. The fecal microbiome of patients with high response had higher abundance of methane and SCFA metabolism pathways compared to patients with no response (p-values < 6 × 10^-3). The genera Ruminococcus 1, Ruminococcaceae UCG-002 and Anaerostipes can be used as predictive biomarkers of diet response. Furthermore, the low-FODMAP diet followers were identifiable given their microbiome data (F1-score of 0.656).

CONCLUSION

Our integrated data analysis results argue that there are two types of patients, those with high colonic methane and SCFA production, who will respond well on a low-FODMAP diet, and all others, who would benefit a dietary supplementation containing butyrate and propionate, as well as probiotics with SCFA-producing bacteria, such as lactobacillus. This work demonstrates how data integration can lead to novel discoveries and paves the way towards personalized diet recommendations for IBS.

Hydrogen-methane breath testing results influenced by oral hygiene

The measurement of hydrogen–methane breath gases is widely used in gastroenterology to evaluate malabsorption syndromes and bacterial overgrowth. Laboratories offering breath testing provide variable guidance regarding oral hygiene practices prior to testing. Given that oral dysbiosis has the potential to cause changes in breath gases, it raises concerns that oral hygiene is not a standard inclusion in current breath testing guidelines. The aim of this study was to determine how a pre-test mouthwash may impact hydrogen–methane breath test results. Participants presenting for breath testing who had elevated baseline gases were given a chlorhexidine mouthwash. If a substantial reduction in expired hydrogen or methane occurred after the mouthwash, breath samples were collected before and after a mouthwash at all breath sample collection points for the duration of testing. Data were evaluated to determine how the mouthwash might influence test results and diagnostic status. In 388 consecutive hydrogen–methane breath tests, modifiable elevations occurred in 24.7%. Administration of a chlorhexidine mouthwash resulted in significantly (p ≤ 0.05) reduced breath hydrogen in 67% and/or methane gas in 93% of those consenting to inclusion. In some cases, this modified the diagnosis. Mean total gas concentrations pre- and post-mouthwash were 221.0 ppm and 152.1 ppm (p < 0.0001) for hydrogen, and 368.9 ppm and 249.8 ppm (p < 0.0001) for methane. Data suggest that a single mouthwash at baseline has a high probability of returning a false positive diagnosis. Variations in gas production due to oral hygiene practices has significant impacts on test interpretation and the subsequent diagnosis. The role of oral dysbiosis in causing gastrointestinal symptoms also demands exploration as it may be an underlying factor in the presenting condition that was the basis for the referral.

Extragastrointestinal Symptoms and Sensory Responses During Breath Tests Distinguish Patients With Functional Gastrointestinal Disorders

INTRODUCTION

Patients with functional gastrointestinal disorders (FGIDs) are classified based on their gastrointestinal (GI) symptoms, without considering their frequent extra-GI symptoms. This study defined subgroups of patients using both GI and extra-GI symptoms and examined underlying mechanisms with fructose and lactose breath tests.

METHODS

Latent class analysis defined distinct clusters of patients with FGID based on their long-term GI and extra-GI symptoms. Sensory and breath gas responses after fructose and lactose ingestion were compared across symptom clusters to investigate differences in sensory function and fermentation by intestinal microbiota.

RESULTS

Six symptom clusters were identified in 2,083 patients with FGID. Clusters were characterized mainly by GI fermentation-type (cluster 1), allergy-like (cluster 2), intense pain-accentuated GI symptoms (cluster 3), central nervous system (cluster 4), musculoskeletal (cluster 5), and generalized extra-GI (cluster 6) symptoms. In the 68% of patients with complete breath tests, the areas under the curve of GI and central nervous system symptoms after fructose and lactose ingestion differed across the clusters (P < 0.001). The clusters with extensive long-term extra-GI symptoms had greater symptoms after the sugars and were predominantly women, with family or childhood allergy histories. Importantly, the areas under the curves of hydrogen and methane breath concentrations were similar (P > 0.05) across all symptom clusters. Rome III criteria did not distinguish between the symptom clusters.

DISCUSSION

Patients with FGID fall into clusters defined extensively by extra-GI symptoms. Greater extra-GI symptoms are associated with evidence of generalized sensory hypersensitivity to sugar ingestion, unrelated to intestinal gas production. Possible underlying mechanisms include metabolites originating from the intestinal microbiota and somatization.

[Importance of functional diagnostics in gastroenterology]

In this review article important and frequently used investigation methods for gastrointestinal functional diagnostics are presented. Some other rarely used special investigations are also explained. The hydrogen breath test is simple to carry out, ubiquitously available and enables the detection of lactose, fructose and sorbitol malabsorption. Furthermore, by the application of glucose, the test can be carried out when there is a suspicion of abnormal intestinal bacterial colonization and using lactulose for measuring small intestinal transit time. The ¹³C urea breath test is applied for non-invasive determination of Helicobacter pylori infections and assessment of gastrointestinal transit time, liver and exocrine pancreas functions. The secretin cholecystokinin test was the gold standard for the detection of exocrine pancreas insufficiency. However, measurement of pancreatic elastase in stool is less invasive but also less sensitive. Scintigraphy and capsule investigations with pH and temperature probes constitute important methods for determination of gastric emptying, intestinal and colon transit times. For evaluation of constipation panoramic abdominal images are taken after intake of radiologically opaque markers (Hinton test). For the diagnosis of functional esophageal diseases manometry is indispensable. In addition, manometry is only occasionally used for diagnosing a dysfunction of the sphincter of Oddi, due to the danger of inducing pancreatitis. A 24 h pH-metry is applied for the detection of non-erosive gastroesophageal reflux disease and, if necessary, with impedance measurements. Recent investigation procedures, e. g. specific MRI sequences, sonographic determination of gall bladder ejection fraction, analysis of gastric accomodation or real-time lumen imaging, require further evaluation prior to clinical application.

Reevaluating our understanding of lactulose breath tests by incorporating hydrogen sulfide measurements

Background and Aim

Breath testing has become a commonly used tool in gastroenterology to evaluate changes in the fermentation pattern of the gut microbiome. Currently, hydrogen and methane gas concentrations are measured in breath testing and evaluated against specific cut‐off values for interpretation as normal or abnormal. However, microbial gas kinetics is a complex process that is not currently fully considered when interpreting breath gas results. Gas exchange between hydrogen producers and hydrogen consumers (methanogens and sulfate‐reducing bacteria) is a process whereby hydrogen availability is determined by both its production and removal. Hydrogen sulfide is a crucial gas involved in this process as it is a major hydrogen‐consumptive pathway involved in energy exchange.

Methods

This is a cross‐sectional study evaluating lactulose breath testing with the inclusion of hydrogen sulfide measurements in patients referred for breath testing for gastrointestinal symptoms of bloating, excessive gas, and/or abdominal pain.

Results

A total of 159 patients were analyzed between October 2016 and June 2017. Mean hydrogen concentrations with a positive trend through a 3‐h period (R² = 0.97), mean methane concentrations with a positive trend (R² = 0.69), and mean hydrogen sulfide concentrations with a negative trend (R² = −0.71) were observed.

Conclusion

By incorporating energy exchange in the interpretation of the lactulose breath test, we reevaluated specific breath gas profiles, including those commonly described as “hydrogen nonproducers” and the “double‐peak” phenomenon.

Repeatability and effect of blinding of fructose breath tests in patients with functional gastrointestinal disorders

BACKGROUND

Breath tests are used as measures of sugar intolerance or malabsorption in patients with functional gastrointestinal disorders (FGID), although the repeatability or anticipatory bias have not been adequately studied. We examined the repeatability and anticipatory bias during fructose breath testing using a nocebo-controlled, randomized, cross-over, and double-blind study design.

METHODS

Gastrointestinal symptoms and breath concentrations of hydrogen and methane were documented during breath tests with fructose (given open twice and blinded once), water (blind neutral nocebo) and a cyclamate/saccharine sweetener (blind sweet nocebo) on 5 days in patients with FGID. Repeatability of fructose breath tests (16 patients) and differences between open and blinded substrate groups (31 patients) was assessed using thresholds for intolerance and malabsorption, and areas-under-the-curve (AUC) of symptoms and breath gas concentrations.

KEY RESULTS

Fructose breath tests showed moderate repeatability for intolerance status (absolute agreement 87%, kappa 0.72), but limited repeatability for malabsorber status (absolute agreement 53%, kappa 0.05). Repeatability of AUCs of GI symptoms, hydrogen and methane breath concentrations was moderate (intraclass correlation coefficients 0.70, 0.57, and 0.57, respectively). There were no significant differences between open and blinded fructose breath tests in intolerance or malabsorber status, or in AUCs of GI symptoms, hydrogen and methane concentrations.

CONCLUSIONS & INFERENCES

Fructose breath tests showed moderate repeatability for intolerance status and for AUCs of symptoms and gas concentrations, lying within the range of accepted gastrointestinal sensory and transit tests. Repeatability for malabsorption status was inadequate and requires revisiting. The fructose breath test can be used unblinded in FGID.

Review article: implementation of a diet low in FODMAPs for patients with irritable bowel syndrome-directions for future research

BACKGROUND

Despite the efficacy of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) for patients with irritable bowel syndrome, many questions remain unanswered with respect to its clinical implementation.

AIM

To review literature to identify, synthesise, and provide direction for future research in the implementation and evaluation of the low FODMAP diet.

METHODS

Bibliographical searches were performed in Ovid Medline, CINAHL, Scopus and PubMed from database commencement until September 2018, with search terms focused on the population (irritable bowel syndrome) and intervention of interest (FODMAP).

RESULTS

Predictors of response to a low FODMAP diet remain under investigation, with preliminary data supporting faecal microbiota or faecal volatile organic compound profiling. Training of clinicians, and standards for the education of patients about the phases of a low FODMAP diet, as well as the role of Apps, require formal evaluation. There are limited data on the longer term efficacy and safety of the low FODMAP diet with respect to sustained symptom control, effect on quality of life and healthcare utilisation, nutritional adequacy, precipitation of disordered eating behaviours, effects on faecal microbiota and metabolomic markers, and subsequent translation to clinical effects.

CONCLUSIONS

Many gaps in implementation of the low FODMAP diet in clinical practice, as well as long-term safety and efficacy, remain for further investigation.

Breath Hydrogen Testing in East and Southeast Asia

Breath hydrogen tests are popular, noninvasive tests for the assessment of carbohydrate fermentation in patients with irritable bowel syndrome (IBS) and functional dyspepsia (FD). There is limited information regarding the utility of breath hydrogen and methane tests in IBS and FD patients in East and Southeast Asia. This review aims to summarize current literature about common indications of breath testing in this region, the genesis of functional gastrointestinal symptoms by provocative breath testing and provide suggestions for correct use. The most common testing indication is the assessment of lactose intolerance, followed by small intestinal bacterial overgrowth (SIBO) and differentiation of intestinal gas profiles in research setting. Studies in this region not only documented a high prevalence of lactose malabsorption but a population, both healthy and IBS, that is highly symptomatic to typical lactose intakes. Breath hydrogen assessment of other fermentable carbohydrates (FODMAPs) are fairly uncommon, whereas methane breath testing is almost nonexistent. Cumulative hydrogen production following lactulose was also not excessive in IBS patients compared with controls. The evidence however, for the detection of SIBO suggests limited reliability in the use of lactulose or glucose breath testing alone and inconclusive data on its correlation with symptoms. Conversely, little has been carried out in FD. In conclusion, breath testing should be limited in the predicting patients with SIBO for directing clinical management but can be considered in the objective assessment of lactose malabsorption within a low FODMAP diet. Recommendations to improve the interpretation of breath testing in research were also provided.

The low FODMAP diet: fundamental therapy in the management of irritable bowel syndrome

PURPOSE OF REVIEW

The low FODMAP diet is now recognized as first-line therapy for treatment of irritable bowel syndrome (IBS) symptoms including abdominal pain, gas, bloating, diarrhea and or constipation. This information must be disseminated for application to clinical practice.

RECENT FINDINGS

There are many people with IBS worldwide who can benefit from following the low FODMAP diet to alleviate or minimize symptoms. Clinical studies and trials demonstrating the positive outcomes of the low FODMAP diet have been based on diet education provided by dietitians. Understanding the types of carbohydrates that are high in FODMAPs and the associated symptoms, nutrition intervention can be targeted using the low FODMAP diet. The nutrition intervention is relatively in expensive, noninvasive and basically without side-effects if monitored by a dietitian and clinical team.

SUMMARY

Applying the low FODMAP diet in IBS can greatly improve health and quality of life outcomes by alleviating or significantly improves symptoms.