Clinical Research Directory

A Study to Investigate Abdominal Symptoms With Camlipixant Compared With Placebo in Adults With Irritable Bowel Syndrome - Diarrhea (IBS-D) and Irritable Bowel Syndrome - Mixed (IBS-M)

This study is designed to evaluate the efficacy and safety of camlipixant in adults with IBS-D and IBS-M. The study has two parts. After the first part, some participants will be randomly chosen again to either get a higher dose or stop the drug.

Home-based Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) for IBS Pain

The goal of this clinical trial is to learn the feasibility and safety of using home-based taVNS in young adults with IBS to manage their IBS-related pain and symptoms. It will also learn about participants' experience in using the home-based taVNS intervention. The main questions it aims to answer are: * Is it feasible to use a home-based taVNS intervention for pain and symptom management among YAs with IBS? * Is it safe and reported satisfactory to use a home-based taVNS intervention for pain and symptom management among YAs with IBS? Researchers will compare Active to Sham taVNS (a look-alike intervention that contains minimal stimulation) to see if Active taVNS works on managing IBS-related pain and symptoms. Participants will: * Take Active or Sham taVNS intervention for a 6-week treatment (twice daily, 30 minutes per session) * Visit the research lab at the initial setup and the end of the 6-week treatment for checkups and tests * Keep a diary of their symptoms and the number of times they use the taVNS.

Exercise Interventions and Dietary Advice in Fibromyalgia and IBS

Fibromyalgia (FM) is a chronic disorder marked by widespread musculoskeletal pain, fatigue, sleep disturbances, and cognitive difficulties. Patients often experience hyperalgesia, allodynia, and muscle weakness. Central sensitization plays a key role, making the nervous system more responsive to pain. Though muscles are mainly affected, joint pain, stiffness, and reduced mobility are also common. Chronic pain and poor posture can worsen musculoskeletal health. FM is not mainly inflammatory, but pain and stress may affect bone health. Sleep disorders, like non-restorative sleep and apnea, are frequent and worsen fatigue. Neurotransmitter imbalances (e.g., serotonin, dopamine) affect pain and muscle function. The American College of Rheumatology defines FM by widespread bilateral pain lasting at least three months. FM mainly affects women, with a prevalence of 0.2-6.6%, often starting between the ages of 30 and 35. Besides physical symptoms, many patients suffer from anxiety, depression, and mood disorders, affecting their quality of life. Gastrointestinal issues, especially irritable bowel syndrome (IBS), are also frequent in FM patients. Both conditions share mechanisms such as pain hypersensitivity, altered autonomic regulation, gut-brain axis disruption, and immune dysfunction. Low-grade inflammation and intestinal permeability may contribute to chronic symptoms. FM treatment includes anticonvulsants, antidepressants, and painkillers. IBS is managed with diet changes and medications like antispasmodics. Due to limited drug effectiveness, multidisciplinary approaches are gaining attention. Physical exercise is a proven non-drug strategy that improves pain, fatigue, and mental health in FM and IBS. Still, adherence is low due to fear of pain, fatigue, and low motivation. Exercise, especially aerobic activity, benefits IBS patients by improving gut symptoms and reducing inflammation. It may also strengthen the gut barrier in both conditions. While optimal programs need more study, exercise is a promising therapy. Major health bodies recommend aerobic, resistance, and flexibility training for FM and aerobic exercise for IBS.

Defining Objective Markers of Compliance for Dietary Therapies in IBS

This research will investigate if a specific marker in your stool or urine can be used to track changes in your carbohydrate intake including fructo-oligosaccharide and mannitol intake

Efficacy and Safety of Encapsulated Bifidobacterium Longum BBH016 in Subjects With Lower Gastrointestinal Symptoms

Functional lower gastrointestinal (GI) symptoms such as abdominal pain, diarrhea, loose stools, and bloating are common in adults without identifiable organic disease and are associated with impaired quality of life and increased healthcare utilization. Growing evidence suggests that alterations in the gut microbiota may contribute to the development of these symptoms, supporting the potential role of probiotics as a therapeutic strategy. Bifidobacterium longum BBH016 is a probiotic strain isolated from a healthy donor and classified as Generally Recognized as Safe (GRAS). Preclinical studies have suggested that BBH016 may alleviate abdominal symptoms, reduce intestinal inflammation, and improve gut microbial balance. This investigator-initiated, randomized, double-blind, placebo-controlled clinical trial aims to evaluate the efficacy and safety of BBH016 capsules in adults with functional lower GI symptoms excluding constipation-predominant presentations. The study will be conducted at Seoul National University Bundang Hospital. A total of 88 participants aged 19-80 years will be randomized in a 1:1 ratio to receive either BBH016 capsules or placebo for 8 weeks (two capsules twice daily). Participants will be assessed at baseline, 4 weeks, and 8 weeks. The primary endpoint is overall improvement in GI symptoms at week 8 compared with baseline between treatment groups. Secondary endpoints include changes in individual symptom scores, IBS Symptom Severity Score (IBS-SSS), IBS Quality of Life (IBS-QoL), stool frequency and form assessed by the Bristol Stool Form Scale, and psychological well-being measured using the Hospital Anxiety and Depression Scale (HADS). Stool samples will also be collected to evaluate changes in the gut microbiome and their association with clinical outcomes.

Neurocognitive Effects of FMT in MDD Patients With and Without IBS

This study is a phase 2/3 open-label controlled trial (CT) in which adults with Major Depressive Disorder (MDD) and adults who have MDD plus comorbid Inflammatory Bowel Syndrome (IBS) will be assigned to either receive oral Fecal Microbiota Transplantation (FMT) or to continue with the treatment they are currently receiving in a Treatment As Usual (TAU) arm. An IBS alone group receiving TAU will be recruited as a clinical control group. The primary goals of this study are to determine effectiveness, safety and tolerability of oral FMT in adults with MDD and in MDD who have comorbid IBS. Additional goals are to characterize patterns and progressions of cognitive and neural correlates associated with MDD and with MDD + IBS and to determine if they improve with FMT. It is known that both, individuals with MDD and those with MDD and IBS show cognitive alterations as well as changes in neural structures, but this study is designed to see if those are changed with treatment response to FMT. Additionally, trial feasibility will be monitored via recruitment rate, study visits adherence and participant retention to inform future trial scalability."

Efficacy of the DOMINO Diet App in IBS

The aim of this study is to evaluate whether the DOMINO diet application is an effective tool in the treatment of Irritable bowel syndrome in tertiary care. Furthermore, this study aims to determine the response rate of the strict low FODMAP diet in non-responders to the DOMINO diet.

Low-FODMAP Diet and Intestinal Permeability in Patients With Irritable Bowel Syndrome

This study aimed to evaluate the effects of a Low-FODMAP diet on intestinal permeability, symptom severity, and quality of life in patients with Irritable Bowel Syndrome (IBS). Twenty-four patients diagnosed with IBS according to the Rome IV criteria were randomized to either a Low-FODMAP diet or a traditional diet for four weeks. Stool zonulin family peptides (ZFP), IBS Symptom Severity Score (IBS-SSS), and IBS Quality of Life (IBS-QOL) questionnaires were recorded at baseline and after the dietary intervention. In the Low-FODMAP group, FODMAP-containing foods were gradually reintroduced under dietitian supervision, and assessments were repeated at week 16 to evaluate long-term effects.

Galactol® Enzyme Supplement for Post-Prandial Abdominal Bloating in Irritable Bowel Syndrome

This multicenter, randomized, controlled clinical trial aims to evaluate the efficacy and safety of a dietary supplement containing a combination of digestive enzymes (alpha-galactosidase, beta-galactosidase, and prolyl-endopeptidase) in reducing post-prandial abdominal bloating in adults diagnosed with irritable bowel syndrome (IBS). Participants will be randomly assigned in a 1:1 ratio to receive either the enzyme supplement (Galactol®) in addition to a diet excluding foods high in FODMAPs, or the diet alone. The intervention will be administered for 14 days. The primary objective is to assess the change in the intensity of post-prandial abdominal bloating measured using a visual analogue scale (VAS). Secondary outcomes include changes in intestinal symptoms, stool consistency, bowel movement frequency, episodes of diarrhea, global gastrointestinal well-being, and treatment tolerability. The results of this study will provide evidence regarding the potential role of enzyme supplementation in reducing gastrointestinal symptoms associated with food-related fermentation in patients with IBS.

Efficacy and Safety Evaluation of Fecal Microbiota Transplantation in Irritable Bowel Syndrome

Participants will be given FMT through oral capsules or nasojejunal tube once a month. After three-time treatment, participants were followed up for three months. Participants complete specific scales to assess improvement in symptoms, emotion and quality of life. Besides, they report adverse effects and collect fecal samples at each visit.

Effectiveness of a Dietary Supplement in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) affects around 5% of the general population and remains a daily problem in clinicians' practices, with inconsistent efficacy of treatments despite patients' high expectations. Intestinal hyperpermeability and visceral hypersensitivity are the two major components of IBS, and both can disrupt gastrointestinal function and ultimately impair patients' quality of life. Glutamine is a non-essential amino acid that regulates numerous metabolic pathways and plays a key role in the intestine as it is the preferred substrate for enterocytes and immune cells. A decrease in intestinal glutamine synthetase has been found in IBS, suggesting its involvement in the intestinal permeability and visceral hypersensitivity observed in patients. Ex vivo, glutamine is capable of restoring the expression of tight junction proteins in IBS-D patients. Furthermore, glutamine supplementation is capable of reducing abdominal pain and restoring intestinal permeability disorders in a sub-group of patients with intestinal permeability disorders (post-infectious IBS-D). The marine peptides Gabolysat® produced by the Dielen Laboratory have demonstrated their efficacy on intestinal permeability and inflammation in a preclinical model of IBS (Langlois et al. 2023), similar to glutamine supplementation in these animals. The Dielen® Protect product formulated on the basis of the results of this study combines glutamine and Gabolysat® to provide a comfort solution for IBS patients. Our working hypothesis is that patients suffering from moderate or severe IBS could benefit from oral supplementation with DIELEN Protect to improve the symptoms associated with IBS. 100 patients with IBS (according to Rome IV criteria) will be included in our study. All patients will test the treatment for 8 weeks (dielen protect or placebo). The efficacy will be compared between the 2 groups before and after the treatments using validated questionnaires. Therefore, all participants will fill questionnaire before and after 8 weeks of treatments : IBS severity (IBS-SSS), quality of life (GIQLI), Anxiety and depression (HAD), GI symptom related anxiety (VSI), stool frequency and consistancy (BSF scale). Microbiota, metabolomic and short chain fatty acid will be analysed before and after the intervention.

Efficacy of Glutamine Supplementation in Patients Suffering From Irritable Bowel Syndrome With Impaired Intestinal Permeability

Irritable bowel syndrome (IBS) affects approximately 5% of the general population and remains a daily problem in the practice of clinicians with inconsistent effectiveness of treatments while patients' expectations are high. One of the functional abnormalities described during IBS is increased intestinal permeability. This increase in intestinal permeability is primarily present in the diarrheal subtype (IBS-D) and can be measured using the lactulose/mannitol test. Glutamine is a non-essential amino acid which regulates numerous metabolic pathways, and which plays a key role in the intestine because it is the preferential substrate of enterocytes and immune cells. Ex vivo, glutamine is able to restore the expression of tight junction proteins in patients suffering from IBS-D. On the other hand, glutamine supplementation is capable of reducing abdominal pain and restoring intestinal permeability disorders in a subgroup of patients with intestinal permeability disorder (post-infectious IBS-D). The working hypothesis would be that all patients suffering from IBS with permeability disorder, measured by the lactulose/mannitol test, could benefit from oral glutamine supplementation.

Pharmacokinetics, Bioequivalence, and Safety Study of Trimedat® 76,95 mg Orally Disintegrating Tablets and Trimedat® 100 mg Tablets in Healthy Volunteers.

This study aims to evaluate pharmacokinetic profile, safety and establish bioequivalence of the investigational drug Trimedat® 76,95 mg orally disintegrating tablets compared to the reference drug Trimedat® 100 mg tablets in healthy volunteers under fasted conditions.

Online Social Learning Program for Parents With Irritable Bowel Syndrome: Raising Resilient Children

The goal of this clinical trial is to test efficacy of the REACH program in parents with irritable bowel syndrome (IBS) and their young children. The main question it aims to answer is: -How can parents with IBS help their young kids develop healthy habits? Participants will be asked to complete online surveys and to use a website. Researchers will compare results from parents who use one of two websites chosen by chance, like flipping a coin. One website focuses on child health and safety behaviors. The other website focuses on strategies to promote child wellness behaviors.

Effects of Aerobic Exercise and Pain Neuroscience Education in Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is a chronic disorder of gut-brain interaction characterized by abdominal pain and changes in bowel habits. The aim of this study is to compare the effects of moderate-intensity aerobic exercise alone and aerobic exercise combined with Pain Neuroscience Education on abdominal pain, IBS symptom severity, quality of life, and salivary cortisol levels in individuals with IBS. Participants will be randomly allocated into three groups: (1) Aerobic Exercise Group, (2) Aerobic Exercise plus Pain Neuroscience Education Group, and (3) Control Group. The aerobic exercise program will consist of supervised walking sessions performed twice weekly for six weeks. Pain Neuroscience Education will be delivered in short, structured sessions over the same six-week period. Assessments will be conducted at baseline and at the end of the intervention. Primary outcomes include abdominal pain intensity, IBS symptom severity, and salivary cortisol levels. Secondary outcomes include quality of life, stool form, and pain-related psychosocial measures. This study aims to provide evidence for non-pharmacological, biopsychosocial approaches in the management of IBS.

Assessment of Psilocybin (TRP-8802) in Concert With Psychotherapy in Patients With Irritable Bowel Syndrome (IBS)

Participants with IBS (all subtypes) and with no exclusionary comorbid psychiatric or medical disorders will be enrolled in the study. This study will involve a randomized waitlist control design to investigate the rapid and sustained effects of TRP-8802 following two experimental sessions in which an oral dose of TRP-8802 is administered to participants with IBS. The study will include clinician and participant ratings of depression and anxiety pre- and post-drug-session, monitor and participant ratings of subjective drug effects during and after each drug session. This study comprises approximately a 28-day screening period (Days 28 to 1). After screening and enrollment, participants will be randomized to an immediate treatment group or a delayed treatment group ("waitlist control" condition). Participants in the immediate treatment group will proceed directly into three weeks of baseline and preparation (Days 1 to 18), a 2-dose administration period (Days 22 and 37), integration (Days 23, 30, 38, and 45), the End of Therapy (EOT) visit (Day 52). Participants in the delayed treatment group will wait 8 weeks after enrollment before beginning the study interventions and neuroimaging assessments. As a safety precaution, participants in the delayed treatment group will be assessed weekly via telephone calls or in-person visits during the wait period (i.e., telephone assessments during post-randomization weeks 1, 2, 3, 4, 5, 6, and 7; in-person assessment during post-randomization week 8) to assess suicide risk to determine if intervention is warranted. During week 8, IBS symptoms will also be assessed. At the end of the delay period, all participants in the delayed treatment group will complete the same intervention as the participants in the immediate treatment group. Validated and commonly used assessment tools will be used to evaluate symptoms at baseline and repeatedly after each session. The weekly average of worst daily pain score and weekly stool frequency and consistency for the 7 days immediately prior to EOT visit will be assessed for change from baseline and at the 3-, 6 , and 12- month follow-up visits (Days 120, 240, 365).

The Mechanism Underlying the Analgesic Effect of the Music of IBS Pain

The proposed pilot study aims to assess the underlying mechanisms of the MBI on IBS pain and the feasibility of using novel technology in the outcome measurements. The specific aims of this pilot mechanistic clinical trial are to: 1. . identify the mechanisms underlying the impact of MBI on IBS-related pain, stress responses, quantitative pain sensitivity, and gut microbiome profiles. 2. . evaluate the technological feasibility of using a wearable abdominal sensor belt and smartwatch system in measuring MBI impacts on pain in home settings. Researchers will conduct a one-arm pre- and post-music intervention among patients with Irritable Bowel Syndrome, collect the IBS pain mechanistic biobehavioral markers, and analyze the underlying pathways of the music analgesic effect. Participants will be asked to: 1. . engage in a 4-week intervention of 20 minutes, both during the day and at night, for at least five days per week. 2. . have two one-hour lab visits

Well-being in IBS: Strengths and Happiness (WISH) 2.0

The purpose of this study is to examine the feasibility, acceptability, preliminary effects, and candidate gut-brain mechanisms of an optimized positive psychology (PP) intervention for patients with irritable bowel syndrome (IBS), entitled "WISH," compared to an educational control intervention.

Drug Interaction Potential of Pro-Inflammatory Conditions

Pro-inflammatory cytokines, which are elevated in pro-inflammatory disease states (e.g., type II diabetes mellitus \[T2DM\], irritable bowel diseases \[IBD\], and end stage renal disease \[ESRD\]) have been shown to inhibit hepatic drug-metabolizing enzymes, including members of the cytochrome P450 (CYP) family, and drug transporters; resultantly, pro-inflammatory diseases have been demonstrated to increase the exposure and potential for adverse drug events with co-administered CYP and drug transporter substrates. However, the clinical relevance of pro-inflammatory disease-drug interactions has not been systematically evaluated. The long-term goal of this research is to establish clinical strategies to mitigate pro-inflammatory disease-drug interactions and associated adverse drug events. The specific objective of this study is to determine the clinical relevance of pro-inflammatory disease-drug interactions, including establishment of the effect of pro-inflammatory diseases on drug disposition throughout disease trajectories (i.e., determining the differential effects on drug disposition based on the severity of disease). Towards this objective, this study will investigate the extent of increases in inflammation in patients with varying severities of pro-inflammatory diseases and estimate the resulting effects on drug disposition. Cytokine/chemokine concentrations and immune cell profiles will be assayed from blood samples of adult and pediatric patients with differing severities of pro-inflammatory diseases, using established disease monitoring parameters (e.g., glycosylated hemoglobin \[HbA1C\] for T2DM, C-reactive protein \[CRP\] for IBD, proteinuria for ESRD). The effect of changes in inflammation during differing severities of these pro-inflammatory diseases on drug disposition will then be estimated using established pharmacokinetic modeling approaches (e.g., physiologically-based pharmacokinetic modeling \[PBPK\]).

Psyllium in Pediatric IBS

The goal of this clinical trial is to learn if a fiber (psyllium) can change the way bacteria use fructans (a type of sugar) and whether psyllium can help decrease childhood irritable bowel syndrome (IBS) symptoms when eating fructans. The main questions it aims to answer are: Aim 1: The effect of psyllium at two doses given with a fructan meal on microbial fructan fermentation (intracolonic pH; H2 gas production; gut microbiome composition; fecal short-chain fatty acids, lactate, glycomics). Aim 2: Determine the impact of psyllium given with a fructan meal on fructan-induced GI symptoms. Participants will first be asked to eat a specific diet over two three-day periods to determine if fructans worsen their IBS symptoms. Those with worsening symptoms with fructans will be asked to participate in the second part of the study. This includes two weeks of baseline (no change in diet) and two weeks of eating a specific diet with fructans with either psyllium or glucose. Participants will be asked to complete pain and stool diaries, submit stool specimens, swallow a pill to capture gut acid levels, and give breath samples.

Irritable Bowel Syndrome Regional Cohort

Setting up a regional (multicentre), longitudinal cohort of people suffering from irritable bowel syndrome followed up in consultation to study the natural history of the disease and its prognosis.

Functional Digestive Disorders Observatory

Functional digestive pathologies are defined by symptoms such as functional dyspepsia, gastroesophageal reflux, irritable bowel syndrome, gastroesophageal reflux, functional constipation, functional diarrhea, functional bloating, the opioid-induced constipation and fecal incontinence, without organic substratum. These diseases are very common in the general population (20%) and represent the first cause of consultation in city gastroenterology. The pathophysiology of these functional disorders is complex and often multifactorial: disturbances in digestive motility, altered visceral sensitivity, sphincter dysfunction, post-surgery, intestinal inflammation, dysbiosis, and impairment of the gut-brain axis. For example, it has been shown that one in four patients with inflammatory bowel disease in confirmed remission report digestive symptoms consistent with a functional bowel disorder, suggesting a possible pathophysiological continuum between these two conditions. The objective of this study is to collect prospective clinical and tests data and a biological collection from biological samples (digestive biopsies, blood, urine and fecal samples) collected as part of the standard care. This collection could identify diagnostic or prognostic markers of the therapeutic response.

Efficacy of a Low FODMAP Diet in the Absence of Lactose Malabsorption in Moderate to Severe ROME IV IBS.

Irritable bowel syndrome (IBS) is a frequently encountered disorder. According to the Rome IV criteria, it is characterized by abdominal pain associated with a change in stool frequency or con-sistency, or with symptomatic improvement by defecation (Mearin 2016). Associated symptoms, such as bloating and flatulence, are frequently reported. The underlying pathophysiology remains obscure, although several pathways have been proposed. Low-grade immune activation, visceral hypersensitivity, alteration in gut microbiome have all been reported (Mearin 2016). As diet exerts an impact on all these pathophysiological mechanisms, the role of dietary intervention receives spe-cial attention, with special interest in the role played by so-called fermentable oligo-, di-, monosac-charides and polyols (FODMAPs). Multiple studies indicated the beneficial effects of the low FODMAP diet in at least part of the patients (Halmos 2014, Eswaran 2016, Staudacher 2017). As a disaccharide, lactose is part of the FODMAPs. Lactose intolerance (LI) results from lactose malabsorption (LM) secondary to insufficient hydrolysis of the disaccharide lactose into galactose and glucose (Misselwitz 2019). The undigested lactose will eventually reach the colon, resulting in fermentation from colonic bacteria with production of different compounds such as short chain fat-ty acids, carbon dioxide, H2 and methane (Catanzaro 2021). These compounds have an osmotic effect and can stimulate colonic contractions. In patients suffering from LI, these pathophysiologi-cal mechanisms generate symptoms such as abdominal pain and cramps, flatulence, diarrhea, in-creased bowel sounds, among others, similar to the mechanisms by which FODMAPs induce symp-toms of IBS. As dairy products are highly present in our Western diet, LI will often be considered in patients presenting with such symptoms and they will be referred for further testing. When LM is diagnosed, a lactose-free diet (LFD) will be advocated to alleviate symptoms. While the earlier-mentioned studies investigated symptomatic improvement by the low FODMAP diet, it remains uncertain whether this restrictive diet remains beneficial in patients without evidence of LM. In a recent study the low FODMAP diet and LFD provided comparable improvement in symptom severity (Krieger-Grübel 2020). This study aims to: * Assess the improvement in IBS symptoms and quality of life (QOL) by a low FODMAP di-et when lactose malabsorption has been previously excluded; * Compare the improvement in IBS symptoms and QOL obtained by a low FODMAP diet to a lactose free diet (data from the PreVaIL study).

Predictive Value of Hydrogen/Methane Lactose Breath Testing on the Therapeutic Effect of Lactose-free Diet in Moderate to Severe ROME IV IBS.

Lactose intolerance (LI) results from lactose malabsorption (LM) secondary to insufficient hydrolysis of the disaccharide lactose into galactose and glucose (Misselwitz 2019). The undigested lactose will eventually reach the colon, resulting in fermentation from colonic bacteria with production of different compounds such as short chain fatty acids, carbon dioxide, H2 and methane (Catanzaro 2021). These compounds have an osmotic effect and can stimulate colonic contractions. These pathophysiological mechanisms encountered in patients suffering from LI generate symptoms, such as abdominal pain and cramps, flatulence, diarrhea, borborygmi among others. As dairy products are highly present in our Western diet, LI will often be considered in patients presenting with these symptoms and they will be referred for further testing. When LM is diagnosed, a lactose-free diet (LFD) will be advocated to alleviate symptoms. However, studies indicate that individuals with LM should tolerate up to 12 g of lactose when administered in a single dose (Suchy 2010). Irritable bowel syndrome (IBS) is another frequently encountered disorder. According to the Rome IV criteria, it is characterized by abdominal pain associated with a change in stool frequency or consistency, or with symptomatic improvement by defecation (Mearin 2016). Associated symptoms, such as bloating and flatulence, are frequently reported. As such, discerning between IBS and LI based on symptoms alone can be challenging. Moreover lactose is considered part of the so-called fermentable oligo-, di-, monosaccharides and polyols (FODMAPs). A low FODMAP diet has been advocated for IBS with beneficial response in at least part of the patients (Halmos 2014). Many studies investigated the role of lactose in IBS. These studies were performed in the pre-Rome IV era and before standardized interpretation rules for Hydrogen breath testing (H2BT) were published (meta-analysis by Varju 2019). This meta-analysis indicated that subjective LI was more frequently reported by IBS patients, but also objectively more prevalent in IBS patients, when assessed by any test modality. However, the role of a LFD in IBS remains uncertain. This study aims to: * Determine if the diagnosis of LM by H2BT predicts the short-term and long-term response to a LFD in moderate to severe IBS as defined by Rome IV criteria; * Determine the changes in quality of life in response to a LFD in ROME IV IBS patients.