Predictors of Symptom-Specific Treatment Response to Dietary Interventions in Irritable Bowel Syndrome

Predictors of response to a dietary intervention in patients with irritable bowel syndrome

BACKGROUND

Different diets have emerged as potential therapeutic options for patients with irritable bowel syndrome (IBS).

OBJECTIVE

To identify predictors of improvement after a low-FODMAP, low-starch and low-sucrose diet among patients with IBS.

METHODS

We performed a descriptive cross-sectional study including patients with IBS according to Rome IV criteria undertaking a social-media based program with a two-week dietary intervention. Patients completed an online survey before and after the intervention including the presence of intestinal and extra-intestinal symptoms, the IBS-SSS (irritable bowel syndrome symptoms severity scale) and the PHQ-9 (patient health questionnaire-9). Clinical improvement was defined as a decrease of at least 50% in IBS-SSS post dietary intervention. Variables associated with symptomatic response were identified with logistic regression analysis. A clinical score to predict response was created and tested with a with a receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 3583 patients with IBS were included. Mean IBS-SSS before and after dietary intervention was 295.5±52.32 and 240±48.66, respectively (p=0.01); 1178 (32.8%) patients showed clinical improvement. A mean basal IBS-SSS >400 (OR 3.04), chronic headache (OR 1.96), and chronic fatigue (OR 1.81) were significantly associated with symptomatic response. Patients with arthralgia (OR 0.41) and/or fibromyalgia (OR 0.33) were less likely to improve. Each variable received the following individuals scores: IBS-SSS >400: +2, chronic headache: +1.5, chronic fatigue: +1, arthralgia: -1, and fibromyalgia: -1. The ROC curve analysis of the proposed score showed an area under the curve of 0.72 (95% CI 0.69-0.76). A score ≥3 had a sensitivity of 72.64% and specificity of 60.56% for predicting symptomatic improvement.

CONCLUSIONS

There are clinical variables that could serve as reliable predictors of response to a low-FODMAP, low-sucrose, low-starch diet among patients with IBS. Further research is needed to understand the link between the presence of extra-intestinal symptoms and clinical improvement after dietary interventions for IBS.

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.

Exploration of differential responses to FODMAPs and gluten in people with irritable bowel syndrome- a double-blind randomized cross-over challenge study

INTRODUCTION

There is large variation in response to diet in irritable bowel syndrome (IBS) and determinants for differential response are poorly understood.

OBJECTIVES

Our aim was to investigate differential clinical and molecular responses to provocation with fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) and gluten in individuals with IBS.

METHODS

Data were used from a crossover study with week-long interventions with either FODMAPs, gluten or placebo. The study also included a rapid provocation test. Molecular data consisted of fecal microbiota, short chain fatty acids, and untargeted plasma metabolomics. IBS symptoms were evaluated with the IBS severity scoring system. IBS symptoms were modelled against molecular and baseline questionnaire data, using Random Forest (RF; regression and clustering), Parallel Factor Analysis (PARAFAC), and univariate methods.

RESULTS

Regression and classification RF models were in general of low predictive power (Q2 ≤ 0.22, classification rate < 0.73). Out of 864 clustering models, only 2 had significant associations to clusters (0.69 < CR < 0.73, p < 0.05), but with no associations to baseline clinical measures. Similarly, PARAFAC revealed no clear association between metabolome data and IBS symptoms.

CONCLUSION

Differential IBS responses to FODMAPs or gluten exposures could not be explained from clinical and molecular data despite extensive exploration with different data analytical approaches. The trial is registered at www.

CLINICALTRIALS

gov as NCT03653689 31/08/2018.

FODMAP meal challenge test: a novel investigation to predict response to low-FODMAP diet in non-constipating irritable bowel syndrome

BACKGROUND

Though a low-FODMAP diet improves 50% irritable bowel syndrome (IBS) patients, regional dietary variations, vegetarianism, and long-term nutritional consequences challenge its implementation. We aimed developing a FODMAP meal challenge test (FMCT). We prospectively studied whether (i) high- than low-FODMAP foods produce more breath H2 among IBS patients than controls; (ii) post-meal symptoms relate to breath H2 ; and (iii) novel FMCT predicts response to a low-FODMAP diet?

METHODS

Forty Rome III IBS and 20 healthy controls underwent an eight-hour H2 breath test following a low- (rice, brinjal, corn, and banana [450 Kcal]) and a high-FODMAP meal (wheat, kidney bean, pulse, and card [450 Kcal]). Breath H2 (every 15 min) and symptoms following low- and high-FODMAP meals were recorded. IBS-symptom severity scores were recorded every month for 3-months on low-FODMAP diet.

RESULTS

Forty Rome III IBS (19 Rome IV positive) were comparable to 20 controls in age and gender. IBS patients (n = 39 excluding one H2 non-producer) and controls produced more breath H2 after high- (greater in IBS) than low-FODMAP meal. Post-meal symptoms were commoner in IBS (4/40 [10%] and 27/40 [67.5%] with low- and high-FODMAP, respectively [P < 0.00001]; none in healthy). IBS patients developing post-high-FODMAP meal symptoms produced greater H2 (18 PPM [IQR 10.5-23] vs 6 [0-7.2]; P < 0.001). A positive FMCT (breath H2  > 10 PPM above basal with symptoms following high-FODMAP food) had sensitivity, specificity, and diagnostic accuracy of 78.6%, 66.6%, and 75.6%, respectively, to predict low-FODMAP diet response.

CONCLUSIONS

The novel FMCT predicts response to a low-FODMAP diet in IBS.

The Disease Spectrum and Natural History of Patients With Abdominal Bloating or Distension: A Longitudinal Study

Background/Aims

Abdominal bloating or distension (AB/D) is a common complaint in the outpatient of gastroenterology department. Since the potential contributors are numerous and complex, a longitudinal study on the disease spectrum and natural history of patients was performed to better understand the key factors of AB/D.

Methods

Consecutive patients with the chief complaint of AB/D referred to the outpatient clinic were screened. Functional gastrointestinal disorders (FGIDs) were diagnosed according to Rome IV criteria. A 3-year follow-up was performed to seek for the changes in symptoms as well as disease spectrum.

Results

A total of 261 participants were enrolled and 139 completed the follow-up. Most patients suffered from moderate to severe symptoms more than 1 day per week. Common causes of AB/D were FGIDs (51.7%) and organic diseases (17.2%). The latter group was older with lower body mass index (BMI). Functional dyspepsia was the most common type of FGIDs in AB/D. The symptoms of 18.0% of participants failed to improve at the end of the 3-year follow-up, and those diagnosed with FGIDs were most likely to continue to suffer. Abdominal pain was a positive predictive factor for good prognosis in the FGIDs group. Besides, only 22.7% of participants had a consistent diagnosis of FGIDs during follow-up.

Conclusions

FGIDs are the most common diagnosis in patients with AB/D. Symptoms were especially hard to be improved. Classification diagnoses of FGIDs in AB/D patients fluctuated significantly over time.

The Role of the FODMAP Diet in IBS

The low FODMAP (fermentable oligosaccharide, disaccharide, monosaccharide, and polyol) diet is a beneficial therapeutic approach for patients with irritable bowel syndrome (IBS). However, how the low FODMAP diet works is still not completely understood. These mechanisms encompass not only traditionally known factors such as luminal distension induced by gas and water but also recent evidence on the role of FOMAPs in the modulation of visceral hypersensitivity, increases in intestinal permeability, the induction of microbiota changes, and the production of short-chain fatty acids (SCFAs), as well as metabolomics and alterations in motility. Although most of the supporting evidence is of low quality, recent trials have confirmed its effectiveness, even though the majority of the evidence pertains only to the restriction phase and its effectiveness in relieving abdominal bloating and pain. This review examines potential pathophysiological mechanisms and provides an overview of the existing evidence on the effectiveness of the low FODMAP diet across various IBS subtypes. Key considerations for its use include the challenges and disadvantages associated with its practical implementation, including the need for professional guidance, variations in individual responses, concerns related to microbiota, nutritional deficiencies, the development of constipation, the necessity of excluding an eating disorder before commencing the diet, and the scarcity of long-term data. Despite its recognized efficacy in symptom management, acknowledging these limitations becomes imperative for a nuanced comprehension of the role of a low FODMAP diet in managing IBS. By investigating its potential mechanisms and evidence across IBS subtypes and addressing emerging modulations alongside limitations, this review aims to serve as a valuable resource for healthcare practitioners, researchers, and patients navigating the intricate landscape of IBS.

Nutrition and Disorders of Gut-Brain Interaction

BACKGROUND

Disorders of gut-brain interaction (DGBIs) have a complex pathophysiology that is often characterized by a relationship between food ingestion and triggering of symptoms. Understanding of the underlying mechanisms and the role of nutrients as a therapeutic target are rapidly evolving.

AIMS AND METHODS

We performed a narrative review of the literature using the following keywords, their acronyms, and their associations: nutrients, disorders of gut-brain interaction; functional dyspepsia; malabsorption; irritable bowel syndrome; diarrhea; constipation.

RESULTS

Functional dyspepsia displayed a significant correlation between volume, fat and/or wheat abundance, chemical composition of ingested food and symptoms of early satiety, fullness and weight loss. Carbohydrate malabsorption is related to enzyme deficiency throughout the GI tract. Food composition and richness in soluble vs. non-soluble fibers is related to constipation and diarrhea. The elimination of fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) has a significant and non-unidirectional impact on irritable bowel syndrome (IBS) symptoms.

CONCLUSIONS

Food volume, nutritive and chemical composition, and its malabsorption are associated with symptom generation in DGBIs. Further multicenter, randomized-controlled clinical trials are needed to clarify the underlying pathophysiology.

Nutrition Considerations in Patients with Functional Diarrhea

PURPOSE

Functional diarrhea (FD) is a functional gastrointestinal disorder that affects a great percentage of the population and has damaging nutritional and psychological effects. In this review, evidence has been assessed and analyzed to provide nutrition considerations and recommendations for patients with functional diarrhea.

RECENT FINDINGS

The traditional irritable bowel syndrome (IBS) diet, the low FODMAP diet, and general recommendations for diarrhea have been established as interventions for FD. Additionally, nutrition outcomes such as vitamin and mineral deficiencies, hydration levels, and mental health status should be at the forefront of assessment. The importance of medical management of FD and IBS-D is established, with many existing evidence-based recommendations and approved medications available. Nutrition management of FD from a registered dietitian/dietitian nutritionist, from symptom control to dietary advice, is imperative. There are no "one-size-fits-all" approaches to nutrition management of FD, but there is promising literature that can shape personalized nutrition interventions from a registered dietitian.

Nutrition, Physical Activity and Supplementation in Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is a chronic, recurrent functional disorder of the intestine diagnosed based on the Rome IV criteria. Individuals suffering from IBS often associate the severity of their symptoms with the food they consume, leading them to limit the variety of foods they eat and seek information that could help them determine the appropriate selection of dietary items. Clear nutritional recommendations have not been established thus far. NICE recommends a rational approach to nutrition and, if necessary, the short-term implementation of a low FODMAP diet. Currently, the FODMAP diet holds the greatest significance among IBS patients, although it does not yield positive results for everyone affected. Other unconventional diets adopted by individuals with IBS lack supporting research on their effectiveness and may additionally lead to a deterioration in nutritional status, as they often eliminate foods with high nutritional value. The role of physical activity also raises questions, as previous studies have shown its beneficial effects on the physical and mental well-being of every individual, and it can further help alleviate symptoms among people with IBS. Supplementation can be a supportive element in therapy. Attention is drawn to the use of probiotics, vitamin D, and psyllium husk/ispaghula. This review aims to analyze the existing scientific research to determine the impact of various food items, physical activity, and dietary supplementation with specific components through dietary supplements on the course of IBS.

Irritable bowel syndrome - controversies in diagnosis and management

INTRODUCTION

The irritable bowel syndrome (IBS) is the best-recognized disorder of gut brain interactions (DGBI). However, it is controversial if the Rome IV criteria iteration for IBS diagnosis is fit for purpose.

AREAS COVERED

This review critically evaluates Rome IV criteria for diagnosis of IBS and addresses clinical considerations in IBS treatment and management, including dietary factors, biomarkers, disease mimics, symptom severity, and subtypes. The role of diet in IBS is critically reviewed along with the influence of the microbiota, including small intestinal bacterial overgrowth.

EXPERT OPINION

Emerging data suggest the Rome IV criteria are more suitable for identifying severe IBS and least useful for sub-diagnostic patients who are still likely to benefit from IBS treatment. Despite convincing evidence that IBS symptoms are diet-driven and often postprandial, a relationship to eating is not a Rome IV diagnostic criterion. Few IBS biomarkers have been identified, suggesting the syndrome is too heterogeneous to be measured by a single marker, and combined biomarker, clinical, dietary, and microbial profiling may be needed for objective characterization. With many organic diseases mimicking and overlapping with IBS, it's important clinicians are knowledgable about this to mitigate the risk of missing comorbid organic intestinal disease and to optimally treat IBS symptoms.

The Usefulness of the Low-FODMAP Diet with Limited Tryptophan Intake in the Treatment of Diarrhea-Predominant Irritable Bowel Syndrome

(1) Background: A low-FODMAP diet is often recommended in the treatment of irritable bowel syndrome, but it does not improve abdominal symptoms in all patients, and an alternative diet is desirable. The purpose of this study was to evaluate the efficacy of a low-FODMAP diet with a concomitant reduction in tryptophan (TRP) intake in irritable bowel syndrome with diarrhea predominance (IBS-D) in relation to its metabolism via the serotonin and kynurenine pathways. (2) Methods: 40 healthy people (Group I, Controls) and 80 patients with IBS-D were included in the study. IBS-D patients were randomly divided into two groups of 40 each (Groups IIA and IIB). In Group IIA, the low-FODMAP diet was recommended, while in Group IIB, the same diet was recommended but with limited TRP intake for 8 weeks. The TRP intake was analyzed with the use of the nutritional calculator. Abdominal complaints were assessed using the Gastrointestinal Symptom Rating Scale (GSRS-IBS), and psychological status was simultaneously determined using two scales: the Hamilton Anxiety Scale (HAM-A) and the Hamilton Depression Scale (HAM-D). TRP and its metabolites: 5-hydoxyindoleacetic acid (5-HIAA), kynurenine (KYN), kynurenic acid (KYNA), and quinolinic acid (QA) were measured in urine using liquid chromatography tandem mass spectrometry (LC-MS/MS). (3) Results: The consumption of TRP per mg/kg/b.w./24 h has decreased in Group IIA from 20.9 ± 2.39 to 17.45 ± 2.41 (16.5%) and in Group IIB from 21.3 ± 2.33 to 14.32 (34.4%). Significantly greater improvement was found after nutritional treatment in patients in Group IIB as compared to Group IIA (GSRS score: 38.1% vs. 49.8%; HAM-A: 38.7% vs. 49.9%; HAM-D: 13.8% vs. 35.0%; p < 0.01). Reducing TRP intake showed a negative correlation with the degree of improvement in the GSRS score. (4) Conclusions: Lowering the TRP content in a low-FODMAP diet may be useful in treating IBS-D.

Mechanisms underlying food-related symptoms in disorders of gut-brain interaction: Course ahead in research and clinical practice

A subgroup of patients with a disorder of gut-brain interaction (DGBI) report symptoms such as abdominal pain, gas-related symptoms, dyspeptic symptoms and loose stool or urgency after meal intake. Therefore, the effect of several dietary therapies including fibre-rich or restrictive diets have already been studied in patients with irritable bowel syndrome, functional abdominal bloating or distention, and functional dyspepsia. However, there is a paucity of studies in the literature on the mechanisms underlying food-related symptoms. Therefore, this review focuses on these potential mechanisms and explains the role of nutrient sensing and tasting, physical considerations, malabsorption or allergy-like reaction to food and its interaction with microbiota. In addition, it emphasizes the importance of future research and clinical practice regarding food-related symptoms in patients with a DGBI.

Low FODMAP diet reduces gastrointestinal symptoms in irritable bowel syndrome and clinical response could be predicted by symptom severity: A randomized crossover trial

BACKGROUND & AIMS

Fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) can provoke symptoms in patients with irritable bowel syndrome (IBS). We aimed to compare the effects of diets with low vs. moderate FODMAP content on gastrointestinal (GI) symptoms and bowel habits, and to identify possible predictors of clinical response to a low FODMAP diet and FODMAP sensitivity in IBS.

METHODS

Adult participants with IBS (Rome IV criteria, n = 29) were included and adhered to two 7-day diet periods, with either low (4 g/day) or moderate (23 g/day) amounts of FODMAPs, in this randomized, double-blind, crossover study. The periods were separated by a wash-out period (≥14 days). IBS-Severity Scoring System (IBS-SSS) and a stool diary (Bristol Stool Form) were completed before and after the diet periods. At baseline, severity of GI symptoms and gut microbial fermentation were assessed (every 15 min, 4 h) during the Lactulose Nutrient Challenge Test (LNCT). Clinical response and FODMAP sensitivity were defined by reduction after low FODMAP period, and increase after moderate FODMAP period in IBS-SSS (≥50 points), respectively.

RESULTS

Severity of GI symptoms (P = 0.04), stool consistency (P = 0.01), and stool frequency (P = 0.01) differed between the interventions, with reduced overall GI symptom severity, abdominal pain intensity and frequency, bowel habits dissatisfaction, and daily life interference (P < 0.05 for all), as well as more firm (P = 0.03) and less frequent (P < 0.01) stools after low FODMAP intervention, but not after moderate FODMAP intervention. A third (34%) responded clinically to the low FODMAP diet, and the response could be predicted by higher IBS-SSS at baseline (P = 0.02). Although modest associations between FODMAP sensitivity (22%) and GI symptoms during LNCT were observed, no independent predictors could be identified.

CONCLUSIONS

A diet low in FODMAPs reduces GI symptoms and affects bowel habits in IBS, compared with a moderate FODMAP diet. Assessment of IBS severity before the intervention may be used to predict clinical response to a low FODMAP diet. Trial registry (http://www.

CLINICALTRIALS

gov): Registered under Clinical Trial number NCT05182593.

Irritable bowel syndrome with food-related symptoms: Future directions in the clinical management

The majority of patients with irritable bowel syndrome (IBS) experiences food-related symptoms, which are associated with high symptom burden, reduced quality of life, increased healthcare consumption and reduced intake of certain nutrients. In this review we aimed to describe a clinically useful approach for physicians, by presenting the latest progress in knowledge and its translation to management in IBS patients with food-related symptoms, as well as the underlying mechanisms involved. The research tools currently available that can be used in the future for a better characterization of this subgroup of patients are also discussed. Working towards this approach could lead to a more individualised work-up and management of IBS patients with food-related symptoms.

Long-term personalized low FODMAP diet in IBS

Irritable bowel syndrome (IBS) patients often resort to dietary interventions to manage their symptoms, as these are frequently exacerbated by various food items. A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) is now considered by many a first-line treatment option for IBS, as it has been found to be superior to alternative dietary interventions. However, concerns have been raised as restricting fermentable carbohydrates might result in nutritional deficits or alter composition and function of the gut microbiome in the long term. The study by Staudacher et al., published in this issue of the journal, is the first prospective study to follow IBS patients after completing all three phases of the low FODMAPs diet (restriction, reintroduction, and personalization), demonstrating that this is safe and effective in long-term, when patients are supervised by a dietician. This mini-review provides an up-to-date overview of the use of fermentable carbohydrate's restrictions for symptom management in IBS patients, while summarizing the current knowledge on the possible mechanisms of action behind low fermentable carbohydrate diet efficacy.