Low fermentable oligo-di-mono-saccharides and polyols diet versus general dietary advice in patients with diarrhea-predominant irritable bowel syndrome: A randomized controlled trial

Irritable Bowel Syndrome: News from an Old Disorder

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder, which can affect all members of a society, regardless of age, sex, race or socioeconomic status. Because of its high prevalence and chronic nature, it represents a significant economic burden. In fact, these patients have a relevant impairment of their quality of life, which limits their work productivity and daily social activities, especially when it is associated with other disorders, such as anxiety and depression. The diagnosis of IBS relies on symptom-based diagnostic criteria with normal results on a limited number of complementary tests that rule out other possible diagnoses. The aetiology of this condition is incompletely established. However, evidence suggests that it is a multifactorial disorder with several different mechanisms that have been implicated as responsible for the symptoms. Since the treatment strategy is usually based on predominant symptoms and their severity, it is important to recognise the underlying mechanisms in order to successfully relief the visceral pain and altered bowel habits. The aim of this non-systematic review of the literature was to explore the pathophysiology and treatment options of IBS, highlighting the most recent evidence, from the new Rome IV criteria to the new drug armamentarium.

Microbial and metabolomic profiles in correlation with depression and anxiety co-morbidities in diarrhoea-predominant IBS patients

BACKGROUND

Psychological co-morbidities in irritable bowel syndrome (IBS) have been widely recognized, whereas less is known regarding the role of gut microbial and host metabolic changes in clinical and psychological symptoms in IBS.

RESULTS

A total of 70 diarrhoea-predominant IBS (IBS-D) patients and 46 healthy controls were enrolled in this study. Stool and urine samples were collected from both groups for 16S rRNA gene sequencing and metabolomic analysis. The results showed that fecal microbiota in IBS-D featured depleted Faecalibacterium (adjusted P = 0.034), Eubacterium rectale group (adjusted P = 0.048), Subdoligranulum (adjusted P = 0.041) and increased Prevotella (adjusted P = 0.041). O-ureido-L-serine, 3,4-dihydroxybenzenesulfonic acid and (R)-2-Hydroxyglutarate demonstrated lower urinary concentrations in IBS-D patients. We further built correlation matrices between gut microbe abundance, differentiated metabolite quantities and clinical parameters. Dialister manifested negative association with IBS severity (r = - 0.285, P = 0.017), anxiety (r = - 0.347, P = 0.003) and depression level (r = - 0.308, P = 0.010). Roseburia was negatively associated with IBS severity (r = - 0.298, P = 0.012). Twenty metabolites correlated with anxiety or depression levels, including 3,4-dihydroxymandelaldehyde with SAS (r = - 0.383, P = 0.001), 1-methylxanthine with SDS (r = - 0.347, P = 0.004) and 1D-chiro-inositol with SAS (r = - 0.336, P = 0.005). In analysis of microbe-metabolite relationship, 3,4-dihydroxymandelaldehyde and 1-methylxanthine were negatively correlated with relative abundance of Clostridiumsensu stricto.

CONCLUSIONS

Our findings demonstrated altered microbial and metabolomic profiles associated with clinically and psychological symptoms in IBS-D patients, which may provide insights for further investigations.

The Evolving Role of Gut Microbiota in the Management of Irritable Bowel Syndrome: An Overview of the Current Knowledge

The intestinal microbiota is one of the most rapidly evolving areas in biology and medicine. Extensive research in the last decade has escalated our understanding of the role of the microbiota in the pathogenesis of several intestinal and extra-intestinal disorders. Marked by high prevalence, substantial morbidity, and enormous costs, irritable bowel syndrome (IBS) is an important chronic gastrointestinal disorder that is widely encountered by gastroenterologists. Despite advances in our understanding of its pathophysiology, curative interventions have yet to be discovered, and therapeutic approaches remain symptom-driven. Recently, accumulating evidence has enlightened the possible impact of an imbalanced gut microbiome in the pathogenesis of IBS. In fact, several studies have documented altered microbiota in patients, while others have shown that IBS severity was associated with a distinct microbiota signature. These findings may pave the way for the use of microbiota manipulation strategies as an attractive option for IBS management, and may have an essential role in efforts to reduce the societal and economic effects of this ever-growing disorder. In this review, we have outlined the results of the latest research on the association between microbiota and IBS and their implications for the clinical management of affected patients.

Adherence to diet low in fermentable carbohydrates and traditional diet for irritable bowel syndrome

OBJECTIVES

Dietary interventions in irritable bowel syndrome (IBS) include a traditional IBS diet following the guidelines from the National Institute for Health and Clinical Excellence and a diet low in fermentable oligo-, di-, monosaccharides and polyols (FODMAPs). The aim of this study was to evaluate the adherence to these diets, food groups difficult to replace, and dietary determinants of symptom improvement.

METHODS

Sixty-six patients with IBS were randomized to a 4-wk low FODMAP or traditional IBS diet. Participants completed 4-d diet diaries before and during the intervention and reported symptoms on the IBS severity scoring system. We described adherence to the diets on the food group and product level and investigated the association between adherence and symptom improvement.

RESULTS

Adherence to the low FODMAP diet was good and consistent: All participants had a comparable shift in the diet's principal components compatible with the guidelines. Most high FODMAP products were well replaced with low FODMAP equivalents. However, total energy intake fell by 25%, mainly owing to a 69% decreased intake of snacks (P < 0.001). The traditional IBS diet did not shift the diet's principal components, and despite the guidelines, consumption of coffee and alcoholic beverages remained rather high (>50% of baseline). Total energy intake fell by 11% (P = 0.15). For both diets, there was a trend toward an association between adherence and symptom improvement (P < 0.10).

CONCLUSION

In both the low FODMAP and traditional IBS diet, certain food groups were difficult to replace. Because adherence may predict symptom improvement, close dietary guidance might enhance the efficacy of both diets.

Effectiveness of Two Dietary Approaches on the Quality of Life and Gastrointestinal Symptoms of Individuals with Irritable Bowel Syndrome

To evaluate the effectiveness of a low FODMAP (fermentable oligosaccharides, monosaccharaides, disaccharides and polyols) diet in the relief of symptoms and an improvement of the quality of life in individuals with irritable bowel syndrome in comparison to a standard diet according to the British Dietetic Association's guidelines. A non-randomized clinical trial of adult patients with IBS was compared two diet interventions. An assessment of symptoms, quality of life, and nutritional status was performed before and after the four-week mark of intervention. Individuals from the Low FODMAP Diet (LFD) group were evaluated on a third moment, after the controlled reintroduction of FODMAPs. A total of 70 individuals were divided in two groups: Low FODMAP Diet (LFD; n = 47) and Standard Diet (SD; n = 23). 57 individuals completed the four-week intervention (LFD; n = 39; SD; n = 18). At the completion of four weeks, the symptoms improved in both groups (LFD: p < 0.01; DC: p < 0.05) but LFD led to a higher relief (p < 0.05), primarily with respect to abdominal pain and diarrhoea. Quality of life improved significantly in both groups, with no significant differences between SD vs LFD (p > 0.05). In the LFD group, the relief of symptoms observed at the four-week mark remained constant after reintroduction of FODMAPs. Both interventions seem to be effective for the relief of symptoms and quality of life, however LFD had higher effectiveness in the former. The results with LFD suggest it can be a preferred approach in individuals with diarrhoeal profile.

The role of diet in irritable bowel syndrome: implications for dietary advice

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder that affects approximately 10% of the population. Diet triggers symptoms in the vast majority of individuals with IBS. In view of this, there has been a focus on the role of diet in IBS. The diets currently being headlined for IBS include (i) traditional dietary advice, (ii) the low fermentable oligo-, di-, mono- saccharides and polyols (FODMAPs) diet and (iii) the gluten-free diet (GFD). Although traditional dietary advice is considered as the first-line dietary therapy, its evidence base is variable, with a few randomized controlled trials (RCTs) exploring the efficacy of this approach, other than for fibre. There are now a growing number of RCTs demonstrating the efficacy of the low FODMAP diet in the short-term, with some emerging data on the long-term 'adapted' low FODMAP diet. There are also several RCTs showing the benefits of a GFD in IBS; however, this concept is hampered with uncertainty as to the mechanism of action. Nevertheless, all of these dietary therapies are viable options for individuals with IBS, with the dietitian and patient engagement at the forefront of achieving success. However, future pragmatic studies are needed to clarify the comparative efficacy and convenience of implementing these various diets into routine life. Moreover, it is imperative to better delineate the concern that restrictive diets - such as the low FODMAP and GFD - may promote nutritional inadequacies, disordered eating behaviours, and lead to detrimental alterations to the gut microbiota.

Management of irritable bowel syndrome with diarrhea: a review of nonpharmacological and pharmacological interventions

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) condition involving numerous potential causative factors (e.g. alterations in gut microbiota, motility, brain-gut axis). Several interventions are available for the management of patients with IBS, but no universal management algorithm currently exists. The aim of this article is to review interventions that may be considered in the management of patients with IBS with diarrhea (IBS-D). Nonpharmacological interventions include dietary and lifestyle modification, which are generally used as first-line therapy. Probiotics have demonstrated efficacy and safety in patients with IBS, but studies are inconsistent in strains examined, dosing, and treatment duration. Psychological therapies (e.g. cognitive behavioral therapy, hypnotherapy) also may improve IBS symptoms. Pharmacological interventions for the management of IBS-D include the US Food and Drug Administration-approved agents eluxadoline, rifaximin, and alosetron, as well as loperamide, smooth muscle antispasmodics, bile acid sequestrants, and antidepressants (i.e. tricyclic antidepressants, selective serotonin reuptake inhibitors). Eluxadoline and rifaximin have been shown to improve abdominal pain and stool consistency in patients with IBS-D. In addition, data indicate that alosetron improves IBS symptoms; however, it is approved only for women with severe IBS-D. Of the three approved agents, rifaximin has the most favorable safety profile. The risk-benefit ratio is an important consideration with every medication, but is especially important in the treatment of functional GI disorders such as IBS-D. Thus, the most troublesome symptoms, quality of life, symptom intensity, and individual patient preferences should be considered when formulating a management plan for patients with IBS-D.

Microbiota: a novel regulator of pain

Among the various regulators of the nervous system, the gut microbiota has been recently described to have the potential to modulate neuronal cells activation. While bacteria-derived products can induce aversive responses and influence pain perception, recent work suggests that "abnormal" microbiota is associated with neurological diseases such as Alzheimer's, Parkinson's disease or autism spectrum disorder (ASD). Here we review how the gut microbiota modulates afferent sensory neurons function and pain, highlighting the role of the microbiota/gut/brain axis in the control of behaviors and neurological diseases. We outline the changes in gut microbiota, known as dysbiosis, and their influence on painful gastrointestinal disorders. Furthermore, both direct host/microbiota interaction that implicates activation of "pain-sensing" neurons by metabolites, or indirect communication via immune activation is discussed. Finally, treatment options targeting the gut microbiota, including pre- or probiotics, will be proposed. Further studies on microbiota/nervous system interaction should lead to the identification of novel microbial ligands and host receptor-targeted drugs, which could ultimately improve chronic pain management and well-being.

Irritable bowel syndrome: how can symptoms and quality of life be improved with diet?

PURPOSE OF REVIEW

This article aims to review the current scientific evidence of dietary approaches to control the symptoms of irritable bowel syndrome (IBS).

RECENT FINDINGS

In the last decade, there was an important evolution in the study of the low fermentable oligo, di, mono-saccharides and polyols (FODMAP) diet (LFD). Current scientific evidence suggests a significant efficacy in the overall control of symptoms. LFD seems to be effective in improving quality of life. Recent studies suggest that LFD is effective and nutritionally well tolerated also in the long term, and longer adherence may contribute to greater effectiveness in improving depression. There is insufficient scientific evidence for the recommendation of gluten exclusion in IBS therapy, and some authors still suggest that the efficacy of this approach results from the limited ingestion of fructans. There is a promising efficacy of pre, pro, and symbiotic supplements, but there is no consensus on the most appropriate and effective strains in each case.

SUMMARY

Given the poor evidence and the pathophysiological variability of IBS, the interest of each therapeutic option should be always evaluated individually. Nevertheless, LFD is currently the dietary approach with a higher degree of scientific evidence.

Within- and Between-Subject Variation in Dietary Intake of Fermentable Oligo-, Di-, Monosaccharides, and Polyols Among Patients with Irritable Bowel Syndrome

BACKGROUND

A diet low in fermentable carbohydrates, fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) is a promising treatment option for patients with irritable bowel syndrome (IBS). In order to correctly estimate and study the intake of FODMAPs, information about within- and between-subject variations in intakes is needed, but is currently lacking.

OBJECTIVES

The aim was to characterize the variation in FODMAP intake among patients with IBS and to calculate how many days of observations are required to capture absolute intakes as well as to rank individuals.

METHODS

Food intake was recorded during 4 consecutive days, and intakes of energy and FODMAPs were calculated. The coefficient of variation within subjects (CVw), coefficient of variation between subjects (CVb), number of days required to estimate an individual's intake, and number of observations required to correctly rank individuals into quartiles of consumption were calculated.

RESULTS

Diet records were provided from 151 women and 46 men with IBS. The reported mean energy intake was 2039 ± 502 kcal among women and 2385 ± 573 kcal among men, and the median FODMAP intakes were 18.7 g (range 3.7-73.4) and 22.8 g (range 3.6-165.7), respectively. The ratio of CVw/CVb for total FODMAP intake was 0.83 for women and 0.67 for men, and below 1 for all FODMAPs. To capture intake of FODMAPs at the individual level, 19 d of observations are required. Ranking individuals within a group would require 2-6 d of observations.

CONCLUSION

There is more variation between subjects than within subjects regarding FODMAP intake. To correctly estimate an individual's absolute intake of FODMAPs, the number of days of diet records required exceeds what is reasonable for a participant to accomplish. However, ranking individuals into quartiles of FODMAP consumption can be achieved using a 4-d food record. This trial was registered at www.clinicaltrials.gov as NCT02107625 and NCT01252550.

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.

New Protocol for Production of Reduced-Gluten Wheat Bread and Pasta and Clinical Effect in Patients with Irritable Bowel Syndrome: A randomised, Double-Blind, Cross-Over Study

It has been suggested that sourdough fermented products have beneficial health effects. Fungal proteases and selected sourdough lactic acid bacteria were used to produce wheat bread and pasta with a reduced-gluten content (<50% of traditional products). Fermentable oligo-, di- and mono- saccharides and polyols and amylase/trypsin inhibitors were also evaluated. The sensorial features of new products were similar to traditional ones. The efficacy of these new products in reducing the severity of symptoms in Irritable Bowel Syndrome (IBS) patients were compared to traditional bread and pasta using a randomized, crossover-controlled trial. While on a strict gluten-free diet, patients were randomized to consume a reduced- or normal-gluten diet for 2weeks; then, patients from both arms started the wash-out period of one week, and subsequently started the final 2-week period on a normal or reduced-gluten diet. Compared to normal-gluten content, the administration of a reduced-gluten content diet resulted in a decrease of the Visual Analogue Scale score (p = 0.042), while no differences were found in the IBS-Severity Score, Hospital Anxiety and Depression Scale, and IBS-Quality of Life. Data herein reported are novel encouraging findings that should spur a new avenue of research aiming to develop products specifically designed for IBS patients.

Sex-Gender Differences in Irritable Bowel Syndrome

Because of the sex-gender differences that are shown in a diversity of physiological and psychological factors, it can be speculated that the clinical presentation of symptoms as well as treatment strategies in women and men with irritable bowel syndrome (IBS) may differ. Studies have revealed that IBS is more common in women than men. As for the IBS subtype, IBS with constipation is significantly more prevalent among women than men. Sex hormones and gender differences may play important roles in the pathophysiology of IBS. However, its pathophysiologic mechanisms still remain largely unknown, and therapeutic implications are limited. Moreover, women IBS patients have been reported to feel more fatigue, depression, anxiety, and lower quality of life than men IBS patients. Furthermore, there has been evidence of differences in the appropriate treatment efficacy to IBS in men and women, although relatively few men are enrolled in most relevant clinical trials. A more sex-gender-oriented approach in the medical care setting could improve understanding of heterogeneous patients suffering from IBS. An individualized and multicomponent approach including sex and gender issues might help improve the treatment of IBS.