Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis

Impact of HADS Anxiety and Depression Scores on the Efficacy of Dietary Interventions for Irritable Bowel Syndrome

BACKGROUND

Anxiety and depression are associated strongly with irritable bowel syndrome (IBS). Dietary therapies are used increasingly in the management of IBS, but the impact of common mental disorders on response to these has not been well studied.

AIMS

To examine whether symptoms compatible with common mental disorders influence response to dietary interventions.

METHODS

Prospective cohort study of adults, with either diarrhoea-predominant or mixed bowel habits, IBS Severity Scoring System [IBS-SSS] score ≥ 75 points. Participants completed the Hospital Anxiety and Depression score (HADS) and attended initially for British Dietary Association advice for IBS. IBS-SSS was re-checked 3 months later to assess response. If primary endpoint (≥ 50 point decrease in IBS-SSS) was not achieved, patients were offered low fermentable oligo-, di- and monosaccharides and polyol diet and repeated IBS-SSS after another 3 months. Secondary endpoints included of change in IBS-SSS and effect of symptom severity on response.

RESULTS

In total, 448 patients took part, average age of 42 years and 79.0% were female. 69.9% of participants had HADS-A scores ≥ 8 and 39.3% with HADS-D scores ≥ 8. Average IBS-SSS score at baseline was 290 (SD 86). No significant difference was noted in achievement of the primary endpoint according to HADS-A scores (53.4% vs. 62.2% by ITT in those with HADS-A ≥ 8 vs. HADS-A < 8, p = 0.09). Patients with HADS-D ≥ 8 were significantly less likely to achieve the primary endpoint compared with those with HADS-D < 8 (43.8% vs. 64.0% by ITT, p < 0.01).

CONCLUSION

Understanding psychological profile of patients can help predicting their response to IBS dietary interventions.

Perceived healthiness of foods, food avoidance and diet-related anxiety in individuals with self-reported irritable bowel syndrome: a cross-sectional study

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder in which the intake of food is known to exacerbate symptoms. Experiencing food related symptoms can lead to avoidance of food, and cause anxiety related to food intake. We aimed to explore perceptions of the healthiness of food, food avoidance, and food-related worry and anxiety among individuals with and without IBS.

METHODS

This study was based on a survey conducted in January-February 2017. In total, 2000 participants aged 20-65 were invited by postal letter randomly obtained through the Swedish state personal address register. The questionnaire included aspects of socioeconomic position, different disorders including IBS and food intolerances, food avoidance, and food-related worry or anxiety.

RESULTS

In total, 538 participants were included in this study, of whom 8.4% (n = 45) reported having IBS. There were few differences regarding the perceived healthiness of foods between individuals with and without IBS. Participants with IBS avoided gluten (OR 3.45, p = 0.002), lactose (OR 5.0, p < 0.001) and alcohol (OR 2.0, p = 0.042) more frequently than individuals without IBS, and avoidance was driven by abdominal pain. Participants with IBS also reported feeling more worried and having anxiety about diet than those without IBS (p = 0.032 and p = 0.002, respectively).

CONCLUSION

This study indicates that individuals with IBS perceive most foods as equally healthy as individuals without IBS. Having IBS increases the odds of avoiding gluten, lactose, and alcohol. Worry and anxiety related to diet were more common among individuals with IBS, and these aspects need to be considered both in clinical practice and in future research.

Comparison of 4-week versus 8-week dietitian-led FODMAP diet group education sessions in tertiary care clinical practice for irritable bowel syndrome: A service evaluation

BACKGROUND

The implementation of the fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet for irritable bowel syndrome (IBS) can be effectively delivered by dietitians in group settings. The initial FODMAP restriction phase is recommended to be followed for 4 weeks; however, limited efficacy data exist for 4-week FODMAP restriction in group education clinical practice.

METHODS

We aimed to compare 4-week versus 8-week FODMAP group treatment pathways on clinical outcomes using a prospective service evaluation design of IBS patients attending FODMAP restriction (baseline) and reintroduction (follow-up) group sessions (between 2015 and 2019). Clinical outcomes included global symptom question (GSQ) measuring satisfactory relief, gastrointestinal symptom rating scale (GSRS), stool frequency (SF), stool consistency using Bristol stool form scale (BSFS), diet acceptability, patient satisfaction with group sessions and dietary adherence. Logistic regression was used to test for differences in treatment effects when clinical outcomes were compared between groups.

RESULTS

Patients (n = 284) included were aged 18 to 86 years (mean ± SD [standard deviation], 44.6 ± 15.5), 80% female, and were split into 4-week (41%, 117/284) versus 8-week (59%, 167/284) pathways with no differences in baseline characteristics. Mean ± SD time gap between baseline and follow-up was 4.6 ± 0.9 weeks in the 4-week pathway and 9.6 ± 3.3 weeks in the 8-week pathway. When groups were compared at follow-up, no statistical differences were observed in any measures (GSQ, GSRS, SF, BSFS, dietary adherence, diet acceptability and patient satisfaction).

CONCLUSION

A 4-week dietitian-led group FODMAP treatment pathway is as clinically effective and maintains patient acceptability when compared to 8-weeks and should be considered as part of routine clinical practice.

Review article: The role of the gut-brain axis in inflammatory bowel disease and its therapeutic implications

BACKGROUND

Treatments targeting the gut-brain axis (GBA) are effective at reducing symptom burden in irritable bowel syndrome (IBS). The prevalence of common mental disorders and IBS-type symptom reporting is significantly higher in inflammatory bowel disease (IBD) than would be expected, suggesting potential GBA effects in this setting. Manipulation of the GBA may offer novel treatment strategies in selected patients with IBD. We present a narrative review of the bi-directional effects of the GBA in IBD and explore the potential for GBA-targeted therapies in this setting.

METHODS

We searched MEDLINE, EMBASE, EMBASE Classic, PsychINFO, and the Cochrane Central Register of Controlled Trials for relevant articles published by March 2024.

RESULTS

The bi-directional relationship between psychological well-being and adverse longitudinal disease activity outcomes, and the high prevalence of IBS-type symptom reporting highlight the presence of GBA-mediated effects in IBD. Treatments targeting gut-brain interactions including brain-gut behavioural treatments, neuromodulators, and dietary interventions appear to be useful adjunctive treatments in a subset of patients.

CONCLUSIONS

Psychological morbidity is prevalent in patients with IBD. The relationship between longitudinal disease activity outcomes, IBS-type symptom reporting, and poor psychological health is mediated via the GBA. Proactive management of psychological health should be integrated into routine care. Further clinical trials of GBA-targeted therapies, conducted in selected groups of patients with co-existent common mental disorders, or those who report IBS-type symptoms, are required to inform effective integrated models of care in the future.

Reply to "Stribling & Ibrahim 2023: Commentary to the Editor"

In response to "Stribling & Ibrahim 2023: Commentary to the Editor", we wish to thank all authors for their interest in our work. The sole motive behind our narrative review, after learning the lesson from the trans-fat history and its impact on the science and food industry, is to prevent harm before it is too late. We agree with the authors regarding the importance of a worldwide unified definition of dietary fibre, but this should not have potential to worsen symptoms of those with functional bowel disorders nor cause more confusion among the public regarding the health benefits of dietary fibre. Thus, we aim to address the authors' views and concerns, and to provide future recommendations, which will be summarised below. The following abbreviations will be used: FBDs, functional bowel disorders; DF, dietary fibre; LMW DF, low molecular weight dietary fibre; HMW DF, high molecular weight dietary fibre.

Patients' experiences of dietary changes during a structured dietary intervention for irritable bowel syndrome

BACKGROUND

Diet plays an important role in management of gastrointestinal (GI) symptoms in patients with irritable bowel syndrome (IBS). Restrictive diets have gained popularity as treatment for IBS, but no studies have examined the patients' experiences of implementing such diets. Thus, the present study aimed to explore the experience of patients with IBS undergoing a structured dietary intervention.

METHODS

Using inductive content analysis, semi-structured interviews were conducted in 19 patients with IBS, who were recruited from a randomised controlled trial evaluating two different restrictive diets for 4 weeks: a diet low in total carbohydrates; and a diet low in fermentable oligo-, di- and monosaccharides and polyols (i.e., FODMAP) combined with traditional IBS dietary advice.

RESULTS

Three main themes developed from the qualitative analysis and together they describe the dietary intervention as supportive, as well as the dietary changes as challenging and contributing to reflection. Patients found the dietary support effective in both initiating and adhering to their dietary changes. Despite the support, the implementation of the diet was perceived as challenging when it interfered with other important aspects of their lives. However, going through the dietary change process, the patients began to reflect on their eating behaviours, which enabled individual dietary adjustments. The adjustments that patients maintained were not only a result of alleviation of GI symptoms, but also based on personal preferences.

CONCLUSIONS

Patients with IBS undergoing restrictive diets appear to benefit from structured support. However, considering the individual patient's life situation and personal preferences, individualised dietary options should be encouraged to achieve long-term dietary changes.

Neuronutritional Approach to Fibromyalgia Management: A Narrative Review

Fibromyalgia (FM) is a complex and common syndrome characterized by chronic widespread pain, fatigue, sleep disturbances, and various functional symptoms without clear structural or pathological causes. Affecting approximately 1-5% of the global population, with a higher prevalence in women, FM significantly impacts patients' quality of life, often leading to considerable healthcare costs and loss of productivity. Despite its prevalence, the etiology of FM remains elusive, with genetic, environmental, and psychological factors, including nutrition, being implicated. Currently, no universally accepted treatment guidelines exist, and management strategies are often symptomatic. This narrative review explores the potential of a neuronutritional approach to FM management. It synthesizes existing research on the relationship between FM and nutrition, suggesting that dietary interventions could be a promising complementary treatment strategy. Various nutritional interventions, including vitamin D, magnesium, iron, and probiotics supplementation, have shown potential in reducing FM symptoms, such as chronic pain, anxiety, depression, cognitive dysfunction, sleep disturbances, and gastrointestinal issues. Additionally, weight loss has been associated with reduced inflammation and improved quality of life in FM patients. The review highlights the anti-inflammatory benefits of plant-based diets and the low-FODMAPs diet, which have shown promise in managing FM symptoms and related gastrointestinal disorders. Supplements such as vitamin D, magnesium, vitamin B12, coenzyme Q10, probiotics, omega-3 fatty acids, melatonin, S-adenosylmethionine, and acetyl-L-carnitine are discussed for their potential benefits in FM management through various mechanisms, including anti-inflammatory effects, modulation of neurotransmitters, and improvement of mitochondrial function. In conclusion, this review underscores the importance of considering neuronutrition as a holistic approach to FM treatment, advocating for further research and clinical trials to establish comprehensive dietary guidelines and to optimize management strategies for FM patients.

[Research progress of metabolomics in children with irritable bowel syndrome]

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder characterized by symptoms such as abdominal pain, diarrhea, constipation, and indigestion. Given its unclear etiology and pathogenesis, and the absence of specific biomarkers, clinical diagnosis and treatment of IBS continue to pose significant challenges. In recent years, metabolomics technology, known for its non-invasive, high-throughput, high-precision, and highly reproducible features, has been widely applied in the diagnosis, treatment, and prognosis of various diseases. Therefore, metabolomics technology is expected to offer novel insights and methodologies for the biological mechanism research, diagnosis, and treatment of IBS. This article reviews recent advancements in the application of metabolomics to IBS, exploring its potential value in the clinical diagnosis and treatment of children with this condition.

The role of the gut microbiome in neuroinflammation and chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most debilitating adverse effects caused by chemotherapy drugs such as paclitaxel, oxaliplatin and vincristine. It is untreatable and often leads to the discontinuation of cancer therapy and a decrease in the quality of life of cancer patients. It is well-established that neuroinflammation and the activation of immune and glial cells are among the major drivers of CIPN. However, these processes are still poorly understood, and while many chemotherapy drugs alone can drive the activation of these cells and consequent neuroinflammation, it remains elusive to what extent the gut microbiome influences these processes. In this review, we focus on the peripheral mechanisms driving CIPN, and we address the bidirectional pathways by which the gut microbiome communicates with the immune and nervous systems. Additionally, we critically evaluate literature addressing how chemotherapy-induced dysbiosis and the consequent imbalance in bacterial products may contribute to the activation of immune and glial cells, both of which drive neuroinflammation and possibly CIPN development, and how we could use this knowledge for the development of effective treatment strategies.

Naturally Occurring Food Chemical Components and Extraintestinal and Gastrointestinal Symptoms in Adults: A Systematic Review

OBJECTIVE

This systematic review aims to synthesise existing literature to examine the relationship between natural food chemical components and reported symptoms.

DESIGN

A systematic literature review was completed. Databases CINAHL (Ebscohost), Medline (Ovid), Scopus, Informit Health and Google Scholar were searched to identify relevant articles. The population included human studies of adults (≥17 years) and excluded those with IgE-mediate food allergies. Studies examining food chemical components or 'food chemical elimination diets' and symptoms were included. Data was synthesised based on clinical conditions and specific food chemical components examined. The risk of bias was assessed using the Academy of Nutrition and Dietetics 'Quality Criteria Checklist: Primary Research'.

RESULTS

Of the 1659 articles retrieved, 21 met inclusion criteria. This included eight randomised controlled trials, four non-randomised controlled trials, four cohort studies with placebo-controlled challenge, one prospective cohort study, three cross sectional cohort studies, one case-controlled study. Available studies support the role of a low-histamine diet for symptoms in chronic urticaria and low-salicylate diet for reducing sino-nasal symptoms in aspirin exacerbated respiratory disease and chronic rhinosinusitis and/or asthma. While further evidence is needed to verify the role of glutamate in respiratory, pain, asthma and gastrointestinal symptoms.

CONCLUSIONS

Food chemical elimination diets may improve condition-specific symptoms across the adult cohorts outlined within this review, with the strongest evidence to support the role of a low-histamine diet for management of symptoms in chronic urticaria and a low-salicylate diet in aspirin exacerbated respiratory disease and/or asthma. Further well-designed trials are needed to elucidate the effect of specific natural food chemical components on symptoms.

TRIAL REGISTRATION

Systematic review number: CRD42022322511.

Comparison of the Nutritional Adequacy of Current Food-Based Very Low Energy Diets: A Review and Nutritional Analysis

Very low energy diets (VLEDs) contain <800 kcal/day and typically comprise formulated meal replacement products with adequate protein and micronutrients. Food-based VLEDs are an alternative approach, but it is uncertain whether they can provide adequate nutrition within an 800 kcal/day restriction. This analysis aimed to assess the nutritional adequacy of food-based VLEDs compared with formula VLEDs. A systematized literature review was conducted to identify balanced food-based VLEDs by searching five scientific databases from inception to 23 March 2023 and online sources between 1 and 7 May 2023. Ultimately, nine diets were analyzed for nutritional content and compared with Codex Alimentarius standards for formula foods, and Australian estimated average requirement and adequate intake (AI) for adults 19-50 years. Optifast® was used as a comparator. None of the VLEDs met all nutritional benchmarks. Three food-based diets had nutrient profiles similar to formula VLEDs, with one being adequate for all nutrients except thiamine, magnesium and zinc in men and iron in women. All VLEDs, including Optifast®, did not meet AI for dietary fiber, except one. In general, food-based VLEDs offered more fiber than Optifast®. In conclusion, food-based VLEDs were inadequate in certain micronutrients but offered more dietary fiber than formula VLEDs. These nutritional deficits do not preclude food-based VLEDs from being recommended, provided they are addressed.

Intestinal Permeability in Disorders of Gut-Brain Interaction: From Bench to Bedside

Intestinal barrier function lies at a critical interface of a range of peripheral and central processes that influence disorders of gut-brain interactions (DGBI). Although rigorously tested, the role of barrier dysfunction in driving clinical phenotype of DGBI remains to be fully elucidated. In vitro, in vivo, and ex vivo strategies can test various aspects of the broader permeability and barrier mechanisms in the gut. Luminal mediators of host, bacterial, and dietary origin can influence the barrier function and a disrupted barrier can also influence the luminal milieu. Critical to our understanding is how barrier dysfunction is influenced by stress and other comorbidities that associate with DGBI and the crosstalk between barrier and neural, hormonal, and immune responses. Additionally, the microbiome's significant role in the communication between the brain and gut has led to the integrative model of a microbiome gut-brain axis with reciprocal interactions between brain networks and networks composed of multiple cells in the gut, including immune cells, enterochromaffin cells, gut microbiota and the derived luminal mediators. This review highlights the techniques for assessment of barrier function, appraises evidence for barrier dysfunction in DGBI including mechanistic studies in humans, as well as provides an overview of therapeutic strategies that can be used to directly or indirectly restore barrier function in DGBI patients.

[The proven and the new in the pharmacotherapy of irritable bowel syndrome]

Irritable bowel syndrome (IBS) is a chronic disease of the digestive tract that is characterised by decades-long chronicity. At the same time, it is particularly challenging to treat since successful treatment often requires a combination of pharmacological and non-pharmacological measures. The pathomechanisms of IBS have only just started to be elucidated, meaning that causally effective treatments are largely lacking. In contrast to earlier notions of a "psychosomatic disorder", IBS is an organic disease in the vast majority of cases. The predominant symptoms are usually intestinal cramps or abdominal pain, meteorism/flatulence, constipation, and diarrhea. The patient should be fully included in a joint treatment concept from the outset. Given the lack of causal treatment methods, each treatment approach is initially by way of trial; if there is no effect, treatment should be discontinued after 3 months at the latest. Effective treatments can be continued, adapted, and/or combined with other procedures as an on-demand or permanent treatment. Supplementing the targeted drug treatment of the dominant individual symptoms with somewhat unspecific but often relevantly effective basic or accompanying treatments has proven useful. Such a multimodal treatment strategy, in which general measures as well as nutritional, psychological, and pharmacotherapies are individually combined, is significantly superior to drug monotherapy. This article describes first- and second-line drug treatments in addition to options for refractory symptoms. The choice of drug therapy is primarily determined by the dominant symptoms. Depending on the symptom constellation, it may be beneficial to combine different drugs.

Probiotics, Prebiotics, Fecal Microbiota Transplantation, and Dietary Patterns in Inflammatory Bowel Disease

SCOPE

Inflammatory bowel disease (IBD) is one of the most common chronic and debilitating functional bowel disorders affecting around 11% of the population across the world. IBD is associated with 3.6 million physician visits per year, being the most common reason visiting a gastroenterologist and the second most common reason to be absent from work, sharply increasing the health care costs.

METHODS AND RESULTS

Several treatments seem to be effective in IBD symptoms relief, such as probiotics, prebiotics, fecal microbiota transplantation (FMT), and dietary patterns. Probiotics (living microorganisms that can be supplemented) can protect against pathogenic bacteria due to their antimicrobial qualities. Prebiotics (nondigestible food ingredients) promote the growth of beneficial microbial strains in the gut, giving a health benefit to the host. FMT is supposed to directly change the recipient's microbial composition when a transfer of gastrointestinal microbiota from a healthy donor is carried out. And finally, dietary patterns are in the spotlight, due to the presence of certain nutrients in the gastrointestinal tract affecting gastrointestinal motility, sensitivity, barrier function, and gut microbiota.

CONCLUSION

It is particularly important to know what treatment options are available and which are the most efficient in relieving IBD symptoms and improving IBD patient's quality of life.

Microbiome-driven IBS metabotypes influence response to the low FODMAP diet: insights from the faecal volatome

BACKGROUND

Irritable bowel syndrome (IBS) is a common and debilitating disorder manifesting with abdominal pain and bowel dysfunction. A mainstay of treatment is dietary modification, including restriction of FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). A greater response to a low FODMAP diet has been reported in those with a distinct IBS microbiome termed IBS-P. We investigated whether this is linked to specific changes in the metabolome in IBS-P.

METHODS

Solid phase microextraction gas chromatography-mass spectrometry was used to examine the faecal headspace of 56 IBS cases (each paired with a non-IBS household control) at baseline, and after four-weeks of a low FODMAP diet (39 pairs). 50% cases had the IBS-P microbial subtype, while the others had a microbiome that more resembled healthy controls (termed IBS-H). Clinical response to restriction of FODMAPs was measured with the IBS-symptom severity scale, from which a pain sub score was calculated.

FINDINGS

Two distinct metabotypes were identified and mapped onto the microbial subtypes. IBS-P was characterised by a fermentative metabolic profile rich in short chain fatty acids (SCFAs). After FODMAP restriction significant reductions in SCFAs were observed in IBS-P. SCFA levels did not change significantly in the IBS-H group. The magnitude of pain and overall symptom improvement were significantly greater in IBS-P compared to IBS-H (p = 0.016 and p = 0.026, respectively). Using just five metabolites, a biomarker model could predict microbial subtype with accuracy (AUROC 0.797, sensitivity 78.6% (95% CI: 0.78-0.94), specificity 71.4% (95% CI: 0.55-0.88).

INTERPRETATION

A metabotype high in SCFAs can be manipulated by restricting fermentable carbohydrate, and is associated with an enhanced clinical response to this dietary restriction. This implies that SCFAs harbour pro-nociceptive potential when produced in a specific IBS niche. By ascertaining metabotype, microbial subtype can be predicted with accuracy. This could allow targeted FODMAP restriction in those seemingly primed to respond best.

FUNDING

This research was co-funded by Addenbrooke's Charitable Trust, Cambridge University Hospitals and the Wellcome Sanger Institute, and supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014).

Fecal microbiota transplantation influences microbiota without connection to symptom relief in irritable bowel syndrome patients

Imbalanced microbiota may contribute to the pathophysiology of irritable bowel syndrome (IBS), thus fecal microbiota transplantation (FMT) has been suggested as a potential treatment. Previous studies on the relationship between clinical improvement and microbiota after FMT have been inconclusive. In this study, we used 16S rRNA gene amplicon and shotgun metagenomics data from a randomized, placebo controlled FMT trial on 49 IBS patients to analyze changes after FMT in microbiota composition and its functional potential, and to identify connections between microbiota and patients' clinical outcome. As a result, we found that the successful modulation of microbiota composition and functional profiles by FMT from a healthy donor was not associated with the resolution of symptoms in IBS patients. Notably, a donor derived strain of Prevotella copri dominated the microbiota in those patients in the FMT group who had a low relative abundance of P. copri pre-FMT. The results highlight the multifactorial nature of IBS and the role of recipient's microbiota in the colonization of donor's strains.

The effect of solid food diet therapies on the induction and maintenance of remission in Crohn's disease: a systematic review

BACKGROUND

The efficacy of highly restrictive dietary therapies such as exclusive enteral nutrition (EEN) in the induction of remission in Crohn's disease (CD) are well established, however, ongoing issues exist with its poor palatability, restrictions, and adherence. The primary aim of this review is to evaluate the current evidence for the efficacy of exclusively solid food diets on the induction and maintenance of clinical and biochemical remission in CD. Secondary aims include impact on endoscopic healing and quality of life.

METHODS

A systematic review of all randomised controlled trials (RCTs), open-label randomised trials and head-to-head clinical trials assessing solid food diet intervention in patients with active or inactive Crohn's disease was conducted. Studies included adult and paediatric patients with a verified disease activity index at baseline and follow up (Harvey Bradshaw Index, HBI; Crohn's disease activity index, CDAI and paediatric CDAI, PCDAI). Additional secondary endpoints varied between studies, including endoscopic and biochemical responses, as well as quality of life measures. Two authors independently performed critical appraisals of the studies, including study selection and risk of bias assessments.

RESULTS

14 studies were included for review, with several studies suggesting clinically significant findings. Clinical remission was achieved in a paediatric population undertaking the Mediterranean diet (MD) (moderate risk of bias). In adults, the Crohn's disease exclusion diet (CDED) was comparable to the CDED with partial enteral nutrition (PEN) diet in induction of remission (moderate risk of bias). A low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet was also shown to decrease symptoms in patients with quiescent or mildly active CD (high risk of bias), however, this was not corroborated by other low FODMAP diet studies.

CONCLUSIONS

There are promising outcomes for the MD and CDED in inducing clinical remission in mild to moderate CD. The results need to be interpreted with caution due to design limitations, including issues with combining outcomes among CD and UC patients, and small sample size. The current evidence for solid food dietary therapy in CD is limited by the lack of high quality studies and moderate to high bias. Future well designed studies are needed to confirm their efficacy.

Review of the Patient Burden and Therapeutic Landscape of Irritable Bowel Syndrome with Constipation in the United States

Irritable bowel syndrome (IBS) is a common disorder of the gut-brain axis. IBS with constipation (IBS-C) accounts for approximately one-third of IBS cases and is associated with substantial burden of illness and decreased quality of life. This narrative review provides an overview of the current and upcoming treatment options and disease management for IBS-C from a US perspective and discusses the importance of the relationship between patient and health care provider in diagnosis and treatment. A positive diagnostic strategy for IBS-C is recommended, based on clinical history, physical examination, and minimal laboratory tests. An effective communication strategy between patients and health care professionals is essential to ensure early diagnosis and reduce both health care costs and overall disease burden. Treatment typically begins with lifestyle interventions and nonpharmacologic options, such as dietary interventions, fiber supplements, and osmotic laxatives. In patients with inadequate response to these therapies, 4 currently available therapies (lubiprostone, linaclotide, plecanatide, and tenapanor) approved by the US Food and Drug Administration may relieve IBS-C symptoms. These agents are generally well tolerated and efficacious in improving IBS-C symptoms, including constipation and abdominal pain. In patients with persistent abdominal pain and/or psychological symptoms, brain-gut behavioral therapy or neuromodulator therapy may be beneficial.

A diet low in fermentable oligo-, di-, monosaccharides and polyols improves abdominal and overall symptoms in persons with all subtypes of irritable bowel syndrome

BACKGROUND

A diet low in fermentable oligo-, di-, monosaccharides and polyols (LFD) improves symptoms in patients with irritable bowel syndrome (IBS). Previous studies have focused on patients with IBS and diarrhea (IBS-D). It is unclear whether LFD is effective for IBS with constipation (IBS-C) or IBS with mixed bowel habits (IBS-M). This open-label, real-world study evaluates the relative effectiveness of the LFD among IBS subtypes.

METHODS

This study analyzes data from a service that provides low-FODMAP meals to individuals with IBS. Participants met with a registered dietitian and completed the IBS symptom severity survey (IBS-SSS) before and after undergoing a 2-4-week period of FODMAP restriction. The primary endpoint was the proportion of participants with ≥50-point decrease in IBS-SSS between the three IBS subtypes.

KEY RESULTS

After FODMAP restriction, 90% of participants with IBS-D, 75% with IBS-C, and 84% with IBS-M met the primary endpoint (p = 0.045). Similar improvement was seen for a 100-point decrease, but the difference between IBS subtypes was not significant (p = 0.46). After FODMAP restriction, all groups had statistically significant improvement in total IBS-SSS as well as individual symptom categories. Improvement in IBS-SSS subcategories was similar among the groups except for the categories of bloating severity (IBS-M had greatest improvement) and bowel movement satisfaction (IBS-C had less improvement).

CONCLUSION & INFERENCES

Though the proportion of responders was highest for IBS-D and lowest for IBS-C, the LFD led to robust improvement in overall symptoms in all IBS subtypes. Key individual symptoms also showed significant improvements in all IBS subtypes.

DOMINO trial post hoc analysis: evaluation of the diet effects on symptoms in IBS subtypes

Background

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction characterized by recurrent abdominal pain related to defecation and/or associated to a change in bowel habits. According to the stool type, four different IBS subtypes can be recognized, constipation predominant (IBS-C), diarrhea predominant (IBS-D), mixed (IBS-M), and undefined (IBS-U). Patients report that their IBS symptoms are exacerbated by food. Thus, it is important to find a nutritional approach that could be effective in reducing IBS symptoms.

Objective

The present work is a post hoc analysis of the previously published DOMINO trial. It aimed to evaluate the effects of a self-instructed FODMAP-lowering diet smartphone application on symptoms and psychosocial aspects in primary care IBS stratifying the results for each IBS subtypes.

Design

Post hoc analysis.

Methods

Two hundred twenty-two primary care IBS patients followed a FODMAP-lowering diet for 8 weeks with the support of a smartphone application. Two follow-up visits were scheduled after 16 and 24 weeks. IBS-Symptoms Severity Score (IBS-SSS), quality of life (QoL), and adherence and dietary satisfaction were evaluated.

Results

After 8 weeks, IBS-SSS improved in all IBS subtypes (p < 0.0001). Physician Health Questiionnaire (PHQ-15) improved only in IBS-D (p = 0.0006), whereas QoL improved both in IBS-D (p = 0.01) and IBS-M (p = 0.005).

Conclusion

This post hoc analysis showed that the app is useful in all IBS subtypes; thus, it could be used as an effective tool by both general practitioners and patients to manage symptoms in primary care.

Trial registration

Ethical Commission University Hospital of Leuven reference number: S59482. Clinicaltrial.gov reference number: NCT04270487.

Influence of a diet meal plan on pepsinogen I and II, gastrin-17, and nutritional status in gastric ulcer patients

BACKGROUND

Gastric ulcers (GUs) have a high risk of clinical morbidity and recurrence, and further exploration is needed for the prevention, diagnosis, and treatment of the disease.

AIM

To investigated the effects of a diet plan on pepsinogen (PG) I, PG II, gastrin-17 (G-17) levels and nutritional status in patients with GUs.

METHODS

A total of 100 patients with GUs treated between May 2022 and May 2023 were enrolled, with 47 patients in the control group receiving routine nursing and 53 patients in the experimental group receiving dietary nursing intervention based on a diet plan. The study compared the two groups in terms of nursing efficacy, adverse events (vomiting, acid reflux, and celialgia), time to symptom improvement (burning sensation, acid reflux, and celialgia), gastric function (PG I, PG II, and G-17 levels), and nutritional status [prealbumin (PA) and albumin (ALB) levels].

RESULTS

The experimental group showed a markedly higher total effective rate of nursing, a significantly lower incidence of adverse events, and a shorter time to symptom improvement than the control group. Additionally, the experimental group's post-intervention PG I, PG II, and G-17 levels were significantly lower than pre-intervention or control group levels, whereas PA and ALB levels were significantly higher.

CONCLUSION

The diet plan significantly reduced PG I, PG II, and G-17 levels in patients with GUs and significantly improved their nutritional status.

Navigating through 65 years of insights: lessons learned on functional abdominal pain in children

In 1958, Apley and Naish authored a groundbreaking paper in Archives of Disease in Childhood, elucidating the epidemiology and risk factors of recurrent abdominal pain in children-a subject that had confounded clinicians of their time. Surprisingly, even after 65 years, there are several unanswered questions regarding the etiology, pathophysiology, and management of pediatric abdominal pain. Contrary to the prevailing notion that children naturally outgrow functional abdominal pain, compelling evidence suggests it's possible these children develop a number of clinically significant psychological issues that could profoundly impact their quality of life and, consequently, future health and educational outcomes. In this light, we aimed to comprehensively review the current literature to update the knowledge of practicing clinicians on functional abdominal pain, summarizing the evidence from the last 65 years.Conclusion: The enduring unanswered questions surrounding childhood abdominal pain continue to challenge clinicians, resulting in unnecessary investigations, thereby contributing to substantial healthcare expenditures. It is also evident that children with long-standing symptoms would progress to adulthood with the potential to develop irritable bowel syndrome and many psychological disturbances. Several key interventions using pharmacological agents, such as amitriptyline, showed that some of these drugs are no more effective than the placebo in clinical trials. Several research during the recent past suggest that psychological interventions such as gut-directed hypnotherapy alleviate symptoms and ensure better prognosis in the long run. Therefore, clinicians and researchers must join hands to explore the pathophysiological mechanisms underpinning functional abdominal pain and novel therapeutic strategies to ensure the well-being of these children. What is Known: • Functional abdominal pain disorders are common among children, with a worldwide prevalence of 13.5% of children suffering from at least one of these disorders • These disorders contribute to a significant reduction in the quality of life of affected children and their families and lead to an array of psychological problems What is New: • The biological basis of functional abdominal pain is becoming more explicit, including complex interactions between altered microbiome, deranged motility, and psychological dysfunction with gut-brain interactions • Novel approaches giving minimal emphasis on pharmacological interventions and exploring psychological interventions are showing promising results.

Coffee, Alcohol, and Artificial Sweeteners Have Temporal Associations with Gastrointestinal Symptoms

BACKGROUND

Various dietary strategies for managing irritable bowel syndrome (IBS) target mechanisms such as brain-gut interactions, osmotic actions, microbial gas production, and local immune activity. These pathophysiological mechanisms are diverse, making it unclear which foods trigger IBS symptoms for a substantial proportion of patients.

AIM

To identify associations between foods and gastrointestinal symptoms.

METHODS

From the mySymptoms smartphone app, we collected anonymized diaries of food intake and symptoms (abdominal pain, diarrhea, bloating, and gas). We selected diaries that were at least 3 weeks long. The diaries were analyzed for food-symptom associations using a proprietary algorithm. As the participants were anonymous, we conducted an app-wide user survey to identify IBS diagnoses according to Rome IV criteria.

RESULTS

A total of 9,710 food symptom diaries that met the quality criteria were collected. Of the survey respondents, 70% had IBS according to Rome IV criteria. Generally, strong associations existed for caffeinated coffee (diarrhea, 1-2 h postprandial), alcoholic beverages (multiple symptoms, 4-72 h postprandial), and artificial sweeteners (multiple symptoms, 24-72 h postprandial). Histamine-rich food intake was associated with abdominal pain and diarrhea. Some associations are in line with existing literature, whilst the absence of an enriched FODMAP-symptom association contrasts with current knowledge.

CONCLUSIONS

Coffee, alcohol, and artificial sweeteners were associated with GI symptoms in this large IBS-predominant sample. Symptom onset is often within 2 h postprandial, but some foods were associated with a delayed response, possibly an important consideration in implementing dietary recommendations. Clinical trials must test the causality of the demonstrated food-symptom associations.

Nutritional safety and status following a 12-week strict low FODMAP diet in patients with irritable bowel syndrome

BACKGROUND

A low FODMAP diet (LFD) is an established dietary treatment for patients with irritable bowel syndrome (IBS). However, knowledge on the extended effects of the restriction phase regarding nutrient intake, symptom severity, and quality of life (QoL) is sparse. Therefore, our objectives were to evaluate the safety of a dietitian-led 12-week strict LFD on measures of blood biochemistry, nutritional status, symptom severity, and QoL.

METHODS

In this open-label dietitian-led 12-week strict LFD intervention for IBS patients with predominantly diarrhea or mixed stool pattern (IBS-D/-M), we collected data on diet intake (3-day dietary record), overnight fasting routine blood samples, body weight, IBS symptoms (IBS Severity Scoring System (IBS-SSS)), and IBS-related QoL (IBS-QoL) at baseline and after 12 weeks.

KEY RESULTS

Thirty-six participants completed the 12-week follow-up (mean age: 37 years, 67% women, IBS-SSS: 242 (101)). All blood parameters measured were within established reference values at both time points. We found no change in intake of macro- or micronutrients, but several micronutrients were below the recommendations both before and after 12 weeks. BMI slightly decreased, primarily driven by participants with BMI >25 (p < 0.005). QoL improved among most subdomains (p ≤ 0.002), except food avoidance and social reaction.

CONCLUSION

An extended dietitian-guided LFD (12 weeks) is not inferior to the participants' baseline diet, since no clinically meaningful changes in nutritionally related blood samples and no changes in macro- or micronutrient intake were observed. However, the intake of several nutrients was below the recommendations at both time points indicating low diet quality.

Innovative concepts in diet therapies in disorders of gut-brain interaction

Diet therapy in disorders of gut-brain interaction (DGBI) is rapidly advancing, with accumulating evidence to support two innovative therapies-manipulation of dietary fibers and enzyme supplementation-that target specific DGBI pathophysiology and modulate digestion. Dietary fibers escape digestion in the upper gastrointestinal tract and can influence gut function by impacting digestion, improving laxation, and interacting with the microbiota. A more nuanced understanding of different fiber types and their ability to impact gut function in highly specific ways has shown that fibers can impact distinct gut symptoms and pathophysiology. By considering their functional characteristics of bulking, gel-forming, and fermentability, restriction or supplementation of specific fibers can offer clinical value in DGBI. Similarly to fiber specificity, emerging evidence suggests that supplemental digestive enzymes may be targeted to known food triggers with consideration that enzymes are substrate specific. Limited evidence supports use of lactase to target lactose, and α-galactosidase to target galacto-oligosaccharides. Application of enzymes during manufacturing of food products may prove to be an additional strategy, although evidence is scant. Both innovative therapies may be utilized in isolation or in combination with other diet and nondiet therapies. Implementation can be guided by the principles that fiber modulation can be targeted to specific symptomology or requirement for alterations to gut function, and digestive enzymes can be targeted to known food triggers. This review aims to summarize recent literature of these two innovative concepts and provide practical suggestions for their implementation in clinical practice.

Beyond Confirmed Mast Cell Activation Syndrome: Approaching Patients With Dysautonomia and Related Conditions

Allergist-immunologists face significant challenges as experts in an ever-evolving field of neuroimmunology. Among these challenges is the increasingly frequent need to counsel patients with suspected mast cell activation disorders about perceived comorbidities, which may include hypermobile Ehlers-Danlos syndrome, amplified pain syndrome, fibromyalgia, burning sensation syndromes, migraines, irritable bowel syndrome, and postural orthostatic tachycardia syndrome. Patients may experience comorbid anxiety, panic disorder, and depression associated with disturbed sleep, fatigue, and cognitive impairment that often worsen when their physical symptoms increase in severity. These conditions may mimic mast cell activation disorders and are emotionally taxing for patients and clinicians because they are often accompanied by vague diagnostic courses, perceived unmanageability, social stigma, and significant impairment in quality of life. Combined with relatively poorly researched therapies, it is no surprise that clinicians may feel overwhelmed or find it difficult to provide consistently compassionate care for this population. In this article, we review available therapies for these conditions, which run the gamut from physical therapy to antidepressants to multimodal pain control. We highlight the benefit of multidisciplinary care within the primary care home, which includes an important role by the allergist-immunologist. By outlining simple approaches to initial treatment, we hope to empower clinicians with the tools needed to curb emotional burnout and embrace this patient population with compassion.

Algorithms or biomarkers in patients with lower DGBI?

BACKGROUND

Several organizations have proposed guidelines or clinical decision tools for the management of patients with disorders of gut-brain interactions (DGBI) affecting the lower digestive tract including irritable bowel syndrome and chronic idiopathic constipation. Such algorithms are based on sequential therapeutic trials and modifying the treatment strategy based on efficacy and adverse events.

PURPOSE

The aims of this review are to evaluate the evidence for efficacy of second- and third-line pharmacotherapies and to assess the evidence for the alternative option to manage subgroups of patients with symptoms suggestive of lower DGBI based on diagnostic tests or documented dysfunctions. The preeminent tests to identify such subgroups that present with symptoms that overlap with lower DGBI are detailed: digital rectal examination as well as anorectal manometry and balloon expulsion for evacuation disorders, detailed measurements of colonic transit, and diagnosis of bile acid diarrhea or carbohydrate malabsorption based on biochemical measurements. The review also addresses the cost implications of screening to exclude alternative diagnoses and the costs of therapy associated with the therapeutic options following an algorithmic approach to treatment from the perspective of society, insurer, or patient. Finally, the costs of the diagnostic tests to identify actionable biomarkers and the evidence of efficacy of individualized therapy based on formal diagnosis or documentation of abnormal functions are detailed in the review.

Challenges of recruitment processes to a randomized dietary trial in irritable bowel syndrome

Background

Irritable bowel syndrome (IBS) is common with a global prevalence of 4%. Dietary regimes with a low content of fermentable oligo-, di-, and monosaccharides and polyol (FODMAP) or a starch- and sucrose-reduced diet (SSRD) have proven to be efficient. The aim of the present study was to describe the recruitment process for a randomized dietary trial with low FODMAP or SSRD for 4 weeks with a follow-up period of 5 months. The results of the dietary trial itself are not included in this paper but will be presented in another publication.

Methods

The County of Skåne, with 1,41 million inhabitants, was used as a base to perform a dietary trial in which IBS patients, age 18-70 years, were randomized to either low FODMAP or SSRD for 4 weeks. The estimated number of IBS patients in the actual age span was approximately 32,000. The trial was announced through lectures, letters to all primary healthcare centers (n=203), social media (two campaigns), and invitations to IBS patients identified in medical records (n=744).

Results

Three referrals arrived from the healthcare system, 17 patients contacted the investigators in person after receiving information from their healthcare center, and four patients contacted the investigators after recommendations from friends. Of these, 14 were enrolled in the study. From social media, 218 names were delivered, of which 93 fulfilled the study criteria and were willing to participate when contacted by the investigators (42.7%). Of the 3587 identified IBS patients in medical records in close proximity to the hospital, 744 were randomly contacted. Forty-eight patients (6.5 %) were willing to be included in the study. Thus, 155 patients with IBS were included in this study.

Conclusions

The inclusion rate for dietary intervention was very low considering the large population informed about the study. Announcements on social media seem to be the best way to recruit patients for intervention.

Trial registration

NCT05192603, 29/11/2021, ClinicalTrials.gov. The PRS URL is https://register.clinicaltrials.gov.

Safety and Tolerability of Microbial Inulinase Supplementation in Healthy Adults: A Randomized, Placebo-Controlled Trial

Background and Aims

Dietary fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) contribute to gastrointestinal (GI) symptoms in individuals with FODMAP sensitivity and irritable bowel syndrome. Oral enzyme supplementation is a strategy to reduce dietary FODMAP exposure and limit FODMAP-associated GI distress. This clinical trial investigated the safety of dietary supplementation with a food-grade, microbial inulinase known to hydrolyze fructan-type or inulin-type FODMAPs and related fructo-oligosaccharides in vitro.

Methods

A randomized, double-blind, placebo-controlled, parallel design trial was conducted in 60 healthy adult participants of both sexes. Following a 2-week run-in placebo phase, participants were randomized to consume inulinase or placebo capsules twice daily with meals for 4 weeks. The total daily dose of inulinase was 2000 inulinase activity units. Safety measures included blood clinical chemistry, hematology, lipid profile, high-sensitivity C-reactive protein, insulin, lactate, and uric acid. GI symptoms were recorded weekly using the 15-item Gastrointestinal Symptom Rating Scale.

Results

Fifty-eight participants completed the study. There were no clinically meaningful between-group differences in blood biomarkers. During the 4-week intervention period, 5 (16.7%) of 30 participants reported 5 adverse events in the inulinase group, and 8 (26.7%) of 30 participants reported 13 adverse events in the placebo group. No statistically significant between-group differences were observed in the change from baseline to 1, 2, 3, or 4 weeks of supplementation with respect to the 15-item Gastrointestinal Symptom Rating Scale overall or domain scores.

Conclusion

Microbial inulinase supplementation demonstrated a favorable safety profile in healthy adults. Further investigation in a dose-ranging study in individuals with dietary FODMAP, fructan, or inulin sensitivity or irritable bowel syndrome is warranted. ClinicalTrials.gov: NCT05744700.

Postprandial symptoms in disorders of gut-brain interaction and their potential as a treatment target

Postprandial, or meal-related, symptoms, such as abdominal pain, early satiation, fullness or bloating, are often reported by patients with disorders of gut-brain interaction, including functional dyspepsia (FD) or irritable bowel syndrome (IBS). We propose that postprandial symptoms arise via a distinct pathophysiological process. A physiological or psychological insult, for example, acute enteric infection, leads to loss of tolerance to a previously tolerated oral food antigen. This enables interaction of both the microbiota and the food antigen itself with the immune system, causing a localised immunological response, with activation of eosinophils and mast cells, and release of inflammatory mediators, including histamine and cytokines. These have more widespread systemic effects, including triggering nociceptive nerves and altering mood. Dietary interventions, including a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols, elimination of potential food antigens or gluten, IgG food sensitivity diets or salicylate restriction may benefit some patients with IBS or FD. This could be because the restriction of these foods or dietary components modulates this pathophysiological process. Similarly, drugs including proton pump inhibitors, histamine-receptor antagonists, mast cell stabilisers or even tricyclic or tetracyclic antidepressants, which have anti-histaminergic actions, all of which are potential treatments for FD and IBS, act on one or more of these mechanisms. It seems unlikely that food antigens driving intestinal immune activation are the entire explanation for postprandial symptoms in FD and IBS. In others, fermentation of intestinal carbohydrates, with gas release altering reflex responses, adverse reactions to food chemicals, central mechanisms or nocebo effects may dominate. However, if the concept that postprandial symptoms arise from food antigens driving an immune response in the gastrointestinal tract in a subset of patients is correct, it is paradigm-shifting, because if the choice of treatment were based on one or more of these therapeutic targets, patient outcomes may be improved.

A low FODMAP diet plus traditional dietary advice versus a low-carbohydrate diet versus pharmacological treatment in irritable bowel syndrome (CARIBS): a single-centre, single-blind, randomised controlled trial

BACKGROUND

Dietary advice and medical treatments are recommended to patients with irritable bowel syndrome (IBS). Studies have not yet compared the efficacy of dietary treatment with pharmacological treatment targeting the predominant IBS symptom. We therefore aimed to compare the effects of two restrictive dietary treatment options versus optimised medical treatment in people with IBS.

METHODS

This single-centre, single-blind, randomised controlled trial was conducted in a specialised outpatient clinic at the Sahlgrenska University Hospital, Gothenburg, Sweden. Participants (aged ≥18 years) with moderate-to-severe IBS (Rome IV; IBS Severity Scoring System [IBS-SSS] ≥175) and no other serious diseases or food allergies were randomly assigned (1:1:1) by web-based randomisation to receive a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) plus traditional IBS dietary advice recommended by the UK National Institute for Health and Care Excellence (hereafter the LFTD diet), a fibre-optimised diet low in total carbohydrates and high in protein and fat (hereafter the low-carbohydrate diet), or optimised medical treatment based on predominant IBS symptom. Participants were masked to the names of the diets, but the pharmacological treatment was open-label. The intervention lasted 4 weeks, after which time participants in the dietary interventions were unmasked to their diets and encouraged to continue during 6 months' follow-up, participants in the LFTD group were instructed on how to reintroduce FODMAPs, and participants receiving pharmacological treatment were offered diet counselling and to continue with their medication. The primary endpoint was the proportion of participants who responded to the 4-week intervention, defined as a reduction of 50 or more in IBS-SSS relative to baseline, and was analysed per modified intention-to-treat (ie, all participants who started the intervention). Safety was analysed in the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02970591, and is complete.

FINDINGS

Between Jan 24, 2017, and Sept 2, 2021, 1104 participants were assessed for eligibility and 304 were randomly assigned. Ten participants did not receive their intervention after randomisation and thus 294 participants were included in the modified intention-to-treat population (96 assigned to the LFTD diet, 97 to the low-carbohydrate diet, and 101 to optimised medical treatment). 241 (82%) of 294 participants were women and 53 (18%) were men and the mean age was 38 (SD 13). After 4 weeks, 73 (76%) of 96 participants in the LFTD diet group, 69 (71%) of 97 participants in the low-carbohydrate diet group, and 59 (58%) of 101 participants in the optimised medical treatment group had a reduction of 50 or more in IBS-SSS compared with baseline, with a significant difference between the groups (p=0·023). 91 (95%) of 96 participants completed 4 weeks in the LFTD group, 92 (95%) of 97 completed 4 weeks in the low-carbohydrate group, and 91 (90%) of 101 completed 4 weeks in the optimised medical treatment group. Two individuals in each of the intervention groups stated that adverse events were the reason for discontinuing the 4-week intervention. Five (5%) of 91 participants in the optimised medical treatment group stopped treatment prematurely due to side-effects. No serious adverse events or treatment-related deaths occurred.

INTERPRETATION

Two 4-week dietary interventions and optimised medical treatment reduced the severity of IBS symptoms, with a larger effect size in the diet groups. Dietary interventions might be considered as an initial treatment for patients with IBS. Research is needed to enable personalised treatment strategies.

FUNDING

The Healthcare Board Region Västra Götaland, the Swedish Research Council, the Swedish Research Council for Health, Working Life and Welfare, AFA Insurance, grants from the Swedish state, the Wilhelm and Martina Lundgren Science Foundation, Skandia, the Dietary Science Foundation, and the Nanna Swartz Foundation.

Organization of Neurogastroenterology and Motility units with a multidisciplinary, patient-centered perspective

Neurogastroenterology and Motility is a Gastroenterology subspecialty dealing with the management of gastrointestinal (GI) motor diseases and disorders of gut-brain interaction (DGBI). Both types of conditions may impair the nutritional status of patients - In the case of motility disorders, because deficient gastrointestinal motility may impair appropriate food digestion and absorption; in DGBI because development of gastrointestinal symptoms may impair appropriate patient nutrition. In both cases, different studies have shown that patients start restrictive diets on their own, without supervision of a dietician, which leads to nutritional deficits in many cases. Likewise, psychological factors like stressful situations or anxiety may trigger gastrointestinal symptoms in these patients, mainly in those with DGBI. Recent studies comparing a patient-centered approach that includes medical treatment, dietary modifications, and behavioural interventions with gastroenterologist-only standard care have shown a greater proportion of improved symptoms, psychological status, and quality of life, as well as reduced costs in patients allocated to the multidisciplinary treatment arm. In conclusion, there is growing evidence in favour of dietary and behavioural interventions by specialized professionals, coupled with appropriate medical evaluation and treatment by a gastroenterologist. Hence the importance of developing reference units in which comprehensive, individualized management may be offered. Multidisciplinary models improve clinical outcomes and patient satisfaction, which should result in a reduction of direct and indirect costs.  .

Chronic Visceral Pain: New Peripheral Mechanistic Insights and Resulting Treatments

Chronic visceral pain is one of the most common reasons for patients with gastrointestinal disorders, such as inflammatory bowel disease or disorders of brain-gut interaction, to seek medical attention. It represents a substantial burden to patients and is associated with anxiety, depression, reductions in quality of life, and impaired social functioning, as well as increased direct and indirect health care costs to society. Unfortunately, the diagnosis and treatment of chronic visceral pain is difficult, in part because our understanding of the underlying pathophysiologic basis is incomplete. In this review, we highlight recent advances in peripheral pain signaling and specific physiologic and pathophysiologic preclinical mechanisms that result in the sensitization of peripheral pain pathways. We focus on preclinical mechanisms that have been translated into treatment approaches and summarize the current evidence base for directing treatment toward these mechanisms of chronic visceral pain derived from clinical trials. The effective management of chronic visceral pain remains of critical importance for the quality of life of suffers. A deeper understanding of peripheral pain mechanisms is necessary and may provide the basis for novel therapeutic interventions.

The efficacy and real-world effectiveness of a diet low in fermentable oligo-, di-, monosaccharides and polyols in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND & AIMS

A diet low in fermentable oligo-, di-, monosaccharides, and polyols (LFD) has been shown to effectively reduce irritable bowel syndrome (IBS) symptoms. Effects resulting from real-world studies may differ from those seen in efficacy studies because of the diversity of patients in real-world settings. This systematic review and meta-analysis aimed to compare the effect of the LFD on reducing IBS symptoms and improving the quality of life (QoL) in efficacy trials and real-world studies.

METHODS

Major databases, trial registries, dissertations, and journals were systematically searched for studies on the LFD in adults with IBS. Meta-analysis was conducted using a random effects model with standardized mean differences (SMD) and 95% confidence intervals (CI). Outcomes of interest were all patient-reported: stool consistency, stool frequency, abdominal pain, overall symptoms, adequate symptom relief, IBS-specific QoL and adherence to the LFD.

RESULTS

Eleven efficacy and 19 real-world studies were reviewed. The meta-analysis results for abdominal pain (SMD 0.35, 95% CI 0.16 to 0.54) and QoL (SMD 0.23, 95% CI -0.05 to 0.50) showed the LFD was beneficial in efficacy studies with no statistically significant results for stool frequency (SMD 0.71, 95% CI 0.34 to 1.07). Real-world studies found improvements in abdominal pain and QoL. Due to heterogeneity, no meta-analysis was done for stool consistency and overall symptoms. In these outcomes, results were mostly supportive of the LFD, but they were not always statistically significant.

CONCLUSIONS

The results of this systematic review and meta-analysis suggest the LFD improves outcomes compared to a control diet (efficacy studies) or baseline data (real-world studies). Because of diverse study designs and heterogeneity of results, a clear superiority of the LFD over control diets could not be concluded. There are no indications of an efficacy-effectiveness gap for the LFD in adults with IBS.

Effects of a low FODMAP diet on the symptom management of patients with irritable bowel syndrome: a systematic umbrella review with the meta-analysis of clinical trials

A low FODMAP diet (LFD) is a common restrictive diet to manage the symptoms of irritable bowel syndrome (IBS). However, there is no consensus on the alleviating effects of this diet. Herein, a systematic umbrella review with meta-analysis was conducted to investigate the effect of an LFD on IBS symptoms and its secondary outcomes in patients, which were not reported in previous meta-analyses. We performed a systematic literature search in PubMed, Scopus, and ISI Web of Science up to December 2023. The methodological quality of systematic reviews and their included trials was evaluated using AMSTAR 2 and the Cochrane risk of bias, respectively. The certainty of the evidence tool was evaluated using the GRADE approach. The data related to IBS symptoms, quality of life (QoL), microbiome diversity, and stool short-chain fatty acids were extracted. A random-effect (if RCTs ≥ 6) or fixed-effect model (if RCTs < 5) was used to recalculate effect sizes and 95% CIs and report them in both qualitative and quantitative terms (pooled risk ratio, Hedges' g, and weighted mean difference). A total of 658 articles were initially identified, with 11 meta-analyses and 24 RCTs reporting 28 outcomes with 1646 participants included. An LFD significantly affected the clinical improvement of total symptoms according to the IBS-SSS questionnaire (RR: 1.42; 95% CI: 1.02, 1.97; P = 0.04) in all the subtypes of IBS and also had favorable effects on stool consistency (WMD: -0.48; 95% CI: -0.902, -0.07) and frequency (WMD: -0.36; 95% CI: -0.61, -0.10) and some other GI symptoms in both less and more than 4 weeks of diet intervention except for stool consistency, which needed more than 4 weeks of LFD implementation. A significant QoL improvement was observed but not in the anxiety and depression state. Furthermore, some studies showed that an LFD may increase fecal pH and dysbiosis and reduce SCFA and the abundance of Bifidobacterium. In conclusion, an LFD can alleviate symptoms and QoL in IBS patients, although dysbiosis may occur. Considering the low certainty of evidence, strong RCTs with more appropriate designs are needed.

Global research trend and hotspot in the low FODMAP diet: a bibliometric analysis

BACKGROUND

According to national guidelines, a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is a second-line therapy option for irritable bowel syndrome (IBS) and improves functional intestinal symptoms. Numerous noteworthy results have been published in this field over the past fifteen years. This study aims to analyze the global research trend and hotspot of the low FODMAP diet research, and provide a comprehensive perspective and direction for researchers.

METHODS

The Science Citation Index-Expanded of the Web of Science Core Collection (WoSCC) was used to identify low FODMAP diet-related articles and reviews. Three bibliometric programs (CiteSpace, VOSviewer, Scimago Graphic) were utilized to analyze and visualize the annual publications, authors, countries, institutions, journals, citations, and keywords.

RESULTS

In total, 843 documents related to the low FODMAP diet research were published in 227 journals by 3,343 authors in 1,233 institutions from 59 countries. The United States, which was the most engaged nation in international collaboration, had the largest annual production and the fastest growth. The most productive organization was Monash University, and the most fruitful researcher was Gibson PR. Nutrients ranked first in terms of the number of published documents. The article "A diet low in FODMAPs reduces symptoms of irritable bowel syndrome" (Halmos EP, 2014) received the most co-citations. Keywords that appear frequently in the literature mainly involve two main aspects: the clinical efficacy evaluation and mechanism exploration of the low FODMAP diet. The term "gut microbiota" stands out as the most prominent keyword among the burst keywords that have remained prevalent till date.

CONCLUSION

The restriction stage of the low FODMAP diet is superior to other dietary therapies for IBS in terms of symptom response, but it has a negative impact on the abundance of gut Bifidobacteria and diet quality. Identification of biomarkers to predict response to the low FODMAP diet is of great interest and has become the current research hotspot.

Is a Simplified, Less Restrictive Low FODMAP Diet Possible? Results from a Double-Blind, Pilot Randomized Controlled Trial

A low fermentable oligo-, mono-, di-saccharides, and polyols (FODMAPs) diet (LFD) is the most evidence-based dietary therapy for patients with irritable bowel syndrome (IBS).1 However, the current step-down approach to the LFD has significant limitations including being costly, complex, time-consuming, and associated with reduced dietary intake of some micronutrients.2-4 Recently, a step-up approach has been proposed that restricts only a limited number of FODMAPs initially, evaluating symptom response and restricting additional FODMAPs only if necessary.2,5,6 In a double-blind trial, fructans and galacto-oligosaccharides were found to be the most likely FODMAP subgroups to trigger IBS symptoms.7 To date, no study has compared the efficacy of a traditional LFD restriction phase with a more targeted or simplified restriction phase. In a double-blind, pilot-feasibility randomized controlled trial, we compared the efficacy of a 4-week FODMAP-simple restriction phase (eliminating solely fructans and galactooligosaccharides) and a traditional LFD restriction phase in patients with IBS with diarrhea (IBS-D) (ClinicalTrials.gov registration number NCT05831306).

All FODMAPs Aren't Created Equal: Results of a Randomized Reintroduction Trial in Patients With Irritable Bowel Syndrome

BACKGROUND & AIMS

A diet low in fermentable oligo, di, monosaccharides, and polyols (FODMAPs) is one of the recommended management strategies for irritable bowel syndrome (IBS). However, while effective, adherence to restricting dietary FODMAPs can be challenging and burdensome. The question remains whether limiting all FODMAPs during the restrictive phase of the diet is necessary for symptomatic improvement in the dietary treatment of IBS, or if targeting selected groups of FODMAPs for restriction is sufficient for clinical response. Our study aimed to determine which individual FODMAPs are most likely to lead to symptom generation in patients with IBS who have improved with fodmap restriction.

METHODS

Patients meeting Rome IV criteria for IBS were invited to participate in a 12-week study to identify individual FODMAP sensitivities. Those subjects who demonstrated symptom improvement after a 2- to 4-week open-label FODMAP elimination period were recruited to a 10-week blinded-phased FODMAP reintroduction phase of 7 days for each FODMAP. Throughout the study period, daily symptom severity (0-10 point numerical rating system) was recorded. A mixed effect statistical analysis model was used.

RESULTS

Between 2018 and 2020, 45 subjects were enrolled. Twenty-five subjects improved with FODMAP elimination, and 21 patients continued into the reintroduction phase of the study. Fructans and galacto-oligosaccharides (GOS) both were associated with worsened abdominal pain (P = .007 and P = .04, respectively). GOS were associated with an increase in bloating (P = 03). Both bloating and abdominal pain worsened throughout the study, regardless of the FODMAP reintroduction (P = .006).

CONCLUSION

Our results suggest that the reintroduction of select FODMAPs may be responsible for symptom generation in patients with IBS who have responded to a low FODMAP diet, and provide a strong rationale for performing a future trial comparing the treatment effects of a limited low-FODMAP diet and a standard low-FODMAP diet.

CLINICALTRIALS

GOV: NCT03052439.

The influence of the gut-brain axis on anxiety and depression: A review of the literature on the use of probiotics

This review aims to argue how using probiotics can improve anxiety and depressive behaviour without adverse effects, also exploring the impact of postbiotics on it. Specifically, probiotics have drawn more attention as effective alternative treatments, considering the rising cost of antidepressant and anti-anxiety drugs and the high risk of side effects. Depression and anxiety disorders are among the most common mental illnesses in the world's population, characterised by low mood, poor general interest, and cognitive or motor dysfunction. Thus, this study analysed published literature on anxiety, depression, and probiotic supplementation from PubMed and Scopus, focusing on the last twenty years. This study focused on the effect of probiotics on mental health as they have drawn more attention because of their extensive clinical applications and positive impact on various diseases. Numerous studies have demonstrated how the gut microbiota might be critical for mood regulation and how probiotics can affect host health by regulating the gut-brain axis. By comparing the different works analysed, it was possible to identify a strategy by which they are selected and employed and, at the same time, to assess how the effect of probiotics can be optimised using postbiotics, an innovation to improve mental well-being in humans.

Can diet change the natural history of gastrointestinal diseases?

Belatedly, gastroenterologists have begun to pay attention to the role of diet in the exacerbation of gastrointestinal symptoms in many digestive disorders-a recognition that has spurred both high-quality clinical trials and translational research into this area. It has become clear that multiple mechanisms acting either in isolation or together can induce gut symptoms and that appropriate interventions can lead to significant relief. What this review will explore is not the role of diet in the production of certain symptoms or symptom clusters, but rather whether a dietary intervention can beneficially alter the natural history of a gastrointestinal disease-a much more demanding expectation. Yet there are examples of where a diet, if sustained, can have a long-term impact on at least some of those affected by conditions such as eosinophilic esophagitis, celiac disease, food allergy, and constipation.

Gut microbiota and intestinal immunity-A crosstalk in irritable bowel syndrome

Irritable bowel syndrome (IBS), one of the most prevalent functional gastrointestinal disorders, is characterized by recurrent abdominal pain and abnormal defecation habits, resulting in a severe healthcare burden worldwide. The pathophysiological mechanisms of IBS are multi-factorially involved, including food antigens, visceral hypersensitivity reactions, and the brain-gut axis. Numerous studies have found that gut microbiota and intestinal mucosal immunity play an important role in the development of IBS in crosstalk with multiple mechanisms. Therefore, based on existing evidence, this paper elaborates that the damage and activation of intestinal mucosal immunity and the disturbance of gut microbiota are closely related to the progression of IBS. Combined with the application prospect, it also provides references for further in-depth exploration and clinical practice.

Case Report: Initial Successful Treatment of Migraine and Irritable Bowel Syndrome With a Low-FODMAP Diet

OBJECTIVE

Migraine and irritable bowel syndrome (IBS) can be difficult-to-treat comorbidities that may be driven by underlying gut-brain axis dysfunction. This report describes utilization of a low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet (LFD) in a patient with refractory migraine and co-occurring IBS.

METHODS

After unremarkable physical and neurological examinations, a 57-year-old woman with IBS and chronic migraine was started on a LFD under the guidance of a registered dietician. Psychometrically validated surveys administered at baseline and initial follow-up assessed patient-reported outcomes related to migraine and IBS symptoms.

RESULTS

At baseline, the patient reported 80/90 migraine days with average pain of 8/10, a Migraine Disability Assessment (MIDAS) score of 33, and Headache Impact Test-6 (HIT-6) score of 64, the latter 2 scores indicating severe disability. Baseline IBS symptom severity was noted at 9/10. Within 1 week on a LFD, the patient's IBS symptoms and migraines improved in both frequency and intensity of episodes. After 5 weeks on a LFD elimination, the patient's clinical improvement continued and she reported significant reduction in migraines, with average pain of 1/10 and IBS severity of 3/10. The patient also improved from severe to minimal levels of disability on validated measures (MIDAS, HIT-6, and IBS Patient Global Impression of Change).

CONCLUSION

This is the first case report detailing successful initial treatment of migraine and co-occurring IBS utilizing a dietician-guided LFD. There are a number of important reasons for potential improvement in these gut-brain axis disorders which are reviewed as well as an implication for long-term management and food reintroduction. Larger, randomized trials evaluating a LFD in diverse individuals with migraine and co-occurring IBS are warranted to help confirm these results.

Evolution, adaptation, and new applications of the FODMAP diet

The FODMAP diet has been a treatment of irritable bowel syndrome (IBS) for many years. Rigorous scientific evaluation and clinical application of the FODMAP diet have generated deep understanding regarding clinical efficacy, mechanisms of action, and potential adverse effects of this dietary approach. In turn, this knowledge has allowed fine-tuning of the diet to optimize treatment benefits and minimize risks, in the form of the traditional three-phase diet; the FODMAP-gentle approach, which is a less restrictive iteration; and a proposed FODMAP-modified, Mediterranean-style diet which endeavours to optimise both gastrointestinal symptoms and other health parameters. Furthermore, recognition that IBS-like symptoms feature in other conditions has seen the FODMAP diet tested in non-IBS populations, including in older adults with diarrhea and women with endometriosis. These areas represent new frontiers for the FODMAP diet and a space to watch as future research evaluates the validity of these novel clinical applications.

Fructose malabsorption and fructan malabsorption are associated in patients with irritable bowel syndrome

BACKGROUND

Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT).

METHODS

We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm.

RESULTS

Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate.

CONCLUSIONS

Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.

Fermented foods and gastrointestinal health: underlying mechanisms

Although fermentation probably originally developed as a means of preserving food substrates, many fermented foods (FFs), and components therein, are thought to have a beneficial effect on various aspects of human health, and gastrointestinal health in particular. It is important that any such perceived benefits are underpinned by rigorous scientific research to understand the associated mechanisms of action. Here, we review in vitro, ex vivo and in vivo studies that have provided insights into the ways in which the specific food components, including FF microorganisms and a variety of bioactives, can contribute to health-promoting activities. More specifically, we draw on representative examples of FFs to discuss the mechanisms through which functional components are produced or enriched during fermentation (such as bioactive peptides and exopolysaccharides), potentially toxic or harmful compounds (such as phytic acid, mycotoxins and lactose) are removed from the food substrate, and how the introduction of fermentation-associated live or dead microorganisms, or components thereof, to the gut can convey health benefits. These studies, combined with a deeper understanding of the microbial composition of a wider variety of modern and traditional FFs, can facilitate the future optimization of FFs, and associated microorganisms, to retain and maximize beneficial effects in the gut.

Causative Factors, Clinical Manifestations, and Therapeutic Strategies for Irritable Bowel Syndrome

Abdominal distress and irregular bowel movements are the hallmarks of irritable bowel syndrome (IBS), a chronic functional gastrointestinal illness (FGID). It is typified by recurring abdominal discomfort brought on by bowel movements or changes in pattern. Mind-body treatments have gained popularity recently as a way to manage IBS because of the role of the brain-gut axis. In addition to offering a helpful guide for identifying alternate diagnoses in patients exhibiting symptoms similar to IBS, this review attempts to offer an evidence-based solution to these perplexing problems. The etiology, diagnostic standards, and treatments for IBS will be summed up in this review, along with a summary of the available data supporting innovative digital medicines for these two illnesses. This brief study will give an overview of the pathophysiology, clinical characteristics, and treatment strategies of post-infectious irritable bowel syndrome (PI-IBS). In this study, we offer thorough methods for therapeutic therapy and talk about the possible contribution of psychological stress to pathophysiology. Additionally, to help with the introduction and suitability of these patient therapies, we offer a comprehensive review and meta-analysis of randomised controlled trials (RCTs) investigating the effectiveness of exclusion diets (low FODMAP and gluten-free diets, etc.) in IBS.

Editorial: A Mediterranean diet for IBS-Is healthy and inclusive eating the way forward?

This article is linked to Staudacher et al paper. To view this article, visit https://doi.org/10.1111/apt.17791

Nutraceuticals and biotics in pediatric gastrointestinal disorders

In recent years there has been growing interest in the use of nutraceuticals and biotics in both pediatric and adult clinical practice. The overlapping and often ambiguous symptoms of both functional and organic gastrointestinal disorders have led to a search for alternative therapeutic approaches that avoid the use of synthetic or chemical treatments. However, while nutraceuticals and natural supplements are widely used, their health benefits are often not supported by adequate scientific evidence, and an unregulated use of nutraceuticals can be potentially harmful. The correct use of nutraceuticals, prebiotics, and probiotics can optimize the results of drug therapy in some cases and reduce the risk of side effects. This review aims to provide clinicians with guidance on the use of complementary therapies for pediatric gastrointestinal symptoms and disorders, highlighting the scarcity of studies on the kinetics and dynamics of nutraceuticals and biotics. While it is generally difficult to associate their intakes with adverse events due to the often-coexisting pharmacological treatments, it is essential to avoid the abandonment of traditional drugs with proven efficacy in the treatment of single diseases. Overall, the use of nutraceuticals, prebiotics, and probiotics in pediatric gastroenterological practice requires caution and medical supervision. Further research is needed to determine the effects of alternative therapies on pediatric gastrointestinal symptoms and disorders, and to ensure their safe and effective use in the clinical practice.