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.

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.

Microbiota modulation in disorders of gut-brain interaction.

Disorders of gut-brain interaction (DGBI) are common chronic conditions characterized by persistent and recurring gastrointestinal symptoms triggered by several pathophysiological factors, including an altered gut microbiota. The most common DGBI are irritable bowel syndrome (IBS), functional constipation (FC) and functional dyspepsia (FD). Recently, a deep understanding of the role of the gut microbiota in these diseases was possible due to multi-omics methods capable to provide a comprehensive assessment. Most of the therapies recommended for these patients, can modulate the gut microbiota such as diet, prebiotics, probiotics and non-absorbable antibiotics, which were shown to be safe and effective. Since patients complain symptoms after food ingestion, diet represents the first line therapeutic approach. Avoiding dietary fat and fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, and increasing the number of soluble fibers represent the therapeutic choices for FD, IBS and FC respectively. Probiotics, as a category, have been employed with good results in all the abovementioned DGBI. Rifaximin has been shown to be useful in the context of bowel related disorders, although a recent trial showed positive results for FD. Fecal microbiota transplantation has been tested for IBS and FC with promising results. In this review, we will briefly summarize the current understanding on dysbiosis and discuss microbiota modulation strategies to treat patients with DGBI.

Irritable bowel syndrome and erectile dysfunction in medical students at a Peruvian university: an analytical cross-sectional analysis.

Background: There is inconclusive evidence regarding the role of irritable bowel syndrome (IBS) in the development of erectile dysfunction (ED), especially among medical students due to high academic stress. Aim: To determine the association between IBS and ED in medical students from a Peruvian university in 2022. Methods: An analytical cross-sectional study was conducted with secondary data analysis on 133 medical students from a university in northern Peru during the 2021-II academic semester. The dependent variable was ED as measured with the 5-item International Index of Erectile Function, and the exposure variable was IBS as assessed with the Rome IV-Bristol questionnaire. Outcomes: The results were the prevalence rates of IBS and ED and the association of these variables. Results: Of the 133 medical students surveyed, the median age was 22 years (IQR, 19-24). The median score on the 5-item International Index of Erectile Function was 21 (IQR, 10-24). The prevalence of ED was 38.4% (95% CI, 30.05%-47.17%). Among the medical students 3% and 9% displayed moderate and severe ED, respectively, and 24.8%, 13.5%, and 24.1% showed moderate depressive, anxious, and severe symptoms. An overall 10.5% had IBS. Medical students with IBS had a 108% higher prevalence of ED than those without the syndrome (prevalence ratio, 2.08; 95% CI, 1.06-4.06). Other confounding variables were not significantly associated (P > .05). Clinical Implications: The results underline the importance of comprehensive sexual and mental health assessment, with an emphasis on the relationship between IBS and ED in medical students. Strengths and Limitations: Strengths include the use of validated and reliable instruments and rigorous biostatistical methods, and this is the first Peruvian investigation to explain the association between IBS and ED in medical students. Limitations include the cross-sectional design and nonprobability sampling, and there may be bias in applying the instruments. Conclusion: This study reveals a significant association between IBS and a higher prevalence of ED in these students.

Gut-Directed Hypnotherapy May Pose Specific Challenges in Gender-Diverse Patients: A Review of 3 Patients.

Disorders of gut-brain interaction are common and often characterized by chronic symptom courses. While gut-directed hypnotherapy is effective for refractory disorders of gut-brain interaction, the required internal awareness and vulnerability may be challenging. Driven by our own clinical experiences, we conducted qualitative interviews with patients who identified as transgender or gender diverse and who had discontinued gut-directed hypnotherapy. Four main themes were generated from these interviews related to distress resulting from body awareness, difficulty with vulnerability, the importance of gender-affirming supports, and external barriers. Providers are encouraged to consider gender diversity, and more broadly body image, in discussion of hypnosis treatment.

Effectiveness of Probiotic Use in Alleviating Symptoms of Irritable Bowel Syndrome: A Systematic Review.

Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) condition, and changes in the gut microbiota's composition contribute to the development of symptoms. Although the precise mechanisms of probiotic use in the human body are not fully understood, probiotic supplements are believed to reduce symptoms, such as abdominal pain, by regulating neurotransmitters and receptors associated with pain modulation in IBS patients compared to placebo by altering the gut flora. This systematic review aimed to assess the most current randomized controlled trials (RCTs) on how probiotic supplementation affects the symptoms in people with IBS. The effects of probiotic supplements on IBS symptoms were studied in RCTs published between January 2018 and June 2023. After a search through PubMed and Google Scholar using the keywords probiotics, gut microbiota, irritable bowel syndrome, and IBS; eight articles matched the inclusion criteria and were reviewed. Four trials used a multistrain probiotic, whereas the remaining four trials examined the effects of a monostrain supplement. All eight trials came to the same conclusion: Probiotic treatment may significantly reduce symptoms.

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.

Lifestyle and genetic predisposition are associated with incident irritable bowel syndrome: A population-based prospective cohort study.

Few prospective studies have investigated the joint effect of lifestyle factors and genetic susceptibility on the risk of irritable bowel syndrome (IBS). This study aims to evaluate the associations of lifestyle and genetic factors with incident IBS in the UK Biobank. We analyzed data from 481,057 participants (54% female) without prevalent IBS at enrollment in the UK Biobank. An overall healthy lifestyle was defined using six modifiable lifestyle factors, including smoking, body mass index (BMI), sleep duration, diet, physical activity, and alcohol consumption, and hence categorized into 'favorable', 'intermediate', and 'unfavorable' lifestyles. A Cox proportional hazard model was used to investigate the association between a healthy lifestyle and incident IBS. Furthermore, we constructed a polygenic risk score (PRS) for IBS and assessed whether lifestyle modified the effect of genetics on the development of IBS. During a median follow-up of 12.1 years, 8645 incident IBS were ascertained. Specifically, among the six modifiable lifestyle factors, adequate sleep demonstrates the greatest protective effect (hazard ratio [HR]: 0.72, 95% CI: 0.69,0.75) against IBS. Compared with a favorable lifestyle, an unfavorable lifestyle was associated with a 56% (95% CI: 46%-67%) increased risk of IBS (P = 8.99 × 10-40). The risk of incident IBS was 12% (95% CI: 4%-21%) higher among those at high genetic risk compared with those at low genetic risk (P = 0.005). When considering the joint effect of lifestyle and genetic susceptibility, the HR nearly doubled among individuals with high genetic risk and unfavorable lifestyle (HR: 1.80; 95% CI:1.51-2.15; P = 3.50 × 10-11) compared to those with low genetic risk and favorable lifestyle. No multiplicative or addictive interaction was observed between lifestyle and genetics. The findings from this study indicated that lifestyle and genetic factors were independently associated with the risk of incident IBS. All these results implicated a possible clinical strategy of lowering the incidence of IBS by advocating a healthy lifestyle.

Small fiber neuropathy in irritable bowel syndrome.

Aim: In this study, we intend to evaluate the occurrence of small fiber neuropathy in patients with irritable bowel syndrome (IBS). Background: Small fiber neuropathy (SFN) is a sensory neuropathy that results from the degeneration of small Aδ and unmyelinated C fibers. SFN manifests positive symptoms, such as tingling, burning, prickling, and aching, and negative symptoms, including numbness, tightness, and coldness. The SFN coexistence with other comorbidities (e.g., fibromyalgia, inflammatory bowel disease, celiac disease) has been reported in previous studies. Methods: We conducted a cross-sectional study to assess the coexistence of SFN and IBS. Forty-two IBS patients and forty-three healthy individuals were asked to complete the Michigan Neuropathy Screening Instrument (MNSI) questionnaire. Results greater than three (>3) were considered positive. Participants with positive MNSI questionnaire results were examined for any neuropathy signs according to the Utah Early Neuropathy Scale (UENS) examination. The participants with positive results for the questionnaire and examination were checked for the sural and the superficial peroneal nerve conduction study (NCS). Normal NCS represented intact large fibers and the diagnosis of SFN. Results: Ten participants, 7 (16.7 %) in the IBS group and 3 (6.9 %) in the healthy group, had positive results for the questionnaire. Four participants were positive for the examination, with normal NCS, and were classified as SFN-positive. All four SFN diagnoses were from the IBS group. No one in the healthy group was diagnosed with SFN. We could find a significant statistical difference (p<0.05) between the IBS and healthy groups regarding the prevalence of SFN diagnosis. Conclusion: The co-occurrence of SFN and IBS suggests the possibility of a generalized neuropathy syndrome characterized by widespread neuronal impairment. Thus, any peripheral neuropathy symptom in IBS patients (and potentially other chronic pain disorders) should be evaluated for SFN since timely diagnosis and proper treatment result in a better quality of life for the patients.

Prevalence and Associated Risk Factors of Irritable Bowel Syndrome Among General Population: A Cross-Sectional Study in Qassim Region, Saudi Arabia.

Background Irritable bowel syndrome (IBS) affects 10-20% of the global population, primarily manifesting as functional issues leading to abdominal discomfort. Key contributors like genetics, psychological factors, weakened immunity, and environmental pollutants play significant roles. Regional variations exist, with prevalence rates ranging from 7-10% in certain areas like South Asia and the Middle East to as high as 20% in many Western countries. Objective The objective of this study is to assess the prevalence of irritable bowel syndrome (IBS) and its related risk factors among the general populace of the Qassim region, Saudi Arabia, aiming to offer valuable insights for healthcare planning and intervention strategies. Methods A cross-sectional descriptive study was conducted, utilizing a validated self-administered questionnaire among residents of the Qassim region aged over 18 years. The questionnaire included demographic information about the participants and the validated Rome IV questionnaire for IBS in adults. Ethical approval for the study was obtained from the Qassim Research Ethics Committee, and data analysis was conducted using R script language version 4.3.3. A significance level of p < 0.05 was employed to interpret the results. Results Overall, significant associations were observed between IBS diagnosis and food allergy (AOR = 2.34, 99% CI: 1.27-4.29), family history of IBS (Adjusted Odd Ratio (AOR) = 7.03, 99% CI: 3.51-15.74), and abdominal pain lasting more than six months (AOR = 2.54, 99% CI: 1.49-4.33). Conclusion This study highlights a high IBS prevalence (21.4%) in Saudi Arabia's Qassim region. While no overall soda-IBS link was found, males showed a protective effect. Significant associations were noted between food allergy, family history, and abdominal pain with IBS diagnosis, especially among females. Further research on gender disparities and familial and abdominal pain roles in IBS management is warranted.

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.

Da-Jian-Zhong decoction alleviates diarrhea-predominant irritable bowel syndrome via modulation of gut microbiota and Th17/Treg balance.

ETHNOPHARMACOLOGICAL RELEVANCE: Da-Jian-Zhong decoction (DJZD) is a herbal formula clinically used for abdominal pain and diarrhea induced by spleen-Yang deficiency syndrome. Recently, treatment of diarrhea-predominant irritable bowel syndrome (IBS-D) with DJZD has received increasing attention, but the underlying mechanism of action remains elusive. AIM OF THE STUDY: We aimed to evaluate the therapeutic effect of DJZD on IBS-D rats and to elucidate the underlying mechanisms. MATERIALS AND METHODS: An IBS-D rats model was constructed using a two-factor superposition method of neonatal maternal separation and Senna folium aqueous extract lavage. Moreover, the effect of DJZD was evaluated based on the body weight, rectal temperature, abdominal withdrawal reflex (AWR), and Bristol stool scale score (BSS). The factors that regulate the DJZD effects on IBS-D were estimated using whole microbial genome, transcriptome sequencing (RNA-Seq), flow cytometry, and quantitative reverse transcription polymerase chain reaction (RT-qPCR) analyses. RESULTS: We found that DJZD alleviated the symptoms of IBS-D rats, with the low-dose (2.4 g/kg) as the better ones, as shown by the higher body weight and lower AWR score and BSS. At the phylum level, the relative abundance of Bacteroidetes was obviously increased, and at the genus level, Lactobacillus and Parabacteroides were increased, while that of Firmicutes_bacterium_424 and Ruminococcus gnavus was decreased in DJZD group. Furthermore, the significantly enriched GO terms after treatment with DJZD mainly included the immune response, positive regulation of activated T cell proliferation, and positive regulation of interleukin-17 (IL-17) production. Importantly, flow cytometry analysis further revealed that the T helper cell type 17/regulatory T cell (Th17/Treg) balance contributed to the DJZD-induced alleviation of IBS-D symptoms, as DJZD downregulated Th17/Treg ratio and Th17 cell-related cytokines IL-17 and IL-6 levels in the colon. CONCLUSIONS: These results demonstrated that DJZD has a good therapeutic effect on IBS-D rats, probably by maintaining the homeostasis of gut microbiota and regulating Th17/Treg balance and its related inflammatory factors.

Management of irritable bowel syndrome: a narrative review.

Background and Objective: As our understanding of the pathophysiology of irritable bowel syndrome (IBS) has advanced, so too has the therapeutic landscape, offering a myriad of approaches to alleviate symptoms and enhance the well-being of patients. This review paper is dedicated to a comprehensive exploration of the diverse therapeutic modalities available for managing IBS. By delving into the complexities of IBS therapeutics, our aim is to contribute to the enhancement of patient care and the overall quality of life for patients grappling with this complex condition. Methods: This review utilized information from PubMed/MEDLINE using the key search term "irritable bowel syndrome" as well as the 2020 American College of Gastroenterology (ACG) and 2022 American Gastroenterological Association (AGA) society guidelines on IBS. The search was restricted to articles in the English language only and included peer-reviewed observational studies and randomized controlled trials (RCTs) in adult patients from April 22, 2020 to October 16, 2023. Key Content and Findings: This review will start with an overview of the current guidelines for pharmacologic therapies for IBS as recommended by the ACG and the AGA, with an emphasis on clinical trials published after the most recent guidelines. It will then delve into the literature on dietary modifications, probiotics, fecal microbiota transplant, behavioral therapy, and complementary and alternative medicine approaches to IBS. Conclusions: It is evident that the management of IBS has transcended a one-size-fits-all approach. As the field of IBS management continues to evolve, it is imperative for physicians to stay informed and receptive to the array of therapeutic options available, ultimately providing patients with the most effective and personalized care.

Investigation of the causal association between Parkinson's disease and autoimmune disorders: a bidirectional Mendelian randomization study.

Background: To date, an increasing number of epidemiological evidence has pointed to potential relationships between Parkinson's disease (PD) and various autoimmune diseases (AIDs), however, no definitive conclusions has been drawn about whether PD is causally related to AIDs risk. Methods: By employing summary statistics from the latest and most extensive genome-wide association studies (GWAS), we performed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal associations between PD and a variety of 17 AIDs, encompassing multiple sclerosis, neuromyelitis optica spectrum disorder, myasthenia gravis, asthma, inflammatory bowel disease, Crohn's disease, ulcerative colitis, irritable bowel syndrome, celiac disease, primary biliary cirrhosis, primary sclerosing cholangitis, type 1 diabetes, ankylosing spondylitis, rheumatoid arthritis, systemic lupus erythematosus, psoriasis and vitiligo. Inverse-variance weighted (IVW) was adopted as the main statistical approach to obtain the causal estimates of PD on different AIDs, supplemented by a series of complementary analyses (weighted median, MR Egger regression, and MR-PRESSO) for further strengthening the robustness of results. Results: Our MR findings suggested that genetically predicted higher liability to PD was causally associated with a decreased risk of irritable bowel syndrome (OR = 0.98; 95% CI: 0.96-0.99; P = 0.032). On the contrary, IVW analysis showed a potential positive correlation between genetically determined PD and the incidence of type 1 diabetes (OR = 1.10; 95%CI: 1.02-1.19; P = 0.010). Subsequent MR tests ended up in similar results, confirming our findings were reliable. Additionally, in the reverse MR analyses, we did not identify any evidence to support the causal relationship of genetic predisposition to AIDs with PD susceptibility. Conclusion: In general, a bifunctional role that PD exerted on the risk of developing AIDs was detected in our studies, both protecting against irritable bowel syndrome occurrence and raising the incidence of type 1 diabetes. Future studies, including population-based observational studies and molecular experiments in vitro and in vivo, are warranted to validate the results of our MR analyses and refine the underlying pathological mechanisms involved in PD-AIDs associations.

Factors associated with irritable bowel syndrome and Helicobacter pylori infection: public knowledge and awareness of signs and symptoms.

OBJECTIVE: To investigate factors related to the risk of developing irritable bowel syndrome (IBS) or Helicobacter pylori infection. METHODS: This cross-sectional, questionnaire-based study analysed the responses from participants that completed an online questionnaire, which asked about their knowledge of the causes and risk factors associated with IBS and H. pylori infection. RESULTS: The study analysed responses from 230 participants: 181 females (of 227 participants; 79.7%) and 190 aged 18-40 years (of 228; 83.3%). Of the 230 participants, 40 (17.4%) had been diagnosed by a physician with IBS and 57 (24.8%) had been diagnosed with H. pylori infection. Of 226 participants, 93 (41.2%) had self-medicated with antibiotics in the past 6 months for various reasons. The overall mean ± SD knowledge score about IBS and H. pylori infection for the study cohort (n = 230) was 35.8 ± 19.2%. Wald χ2-test analysis demonstrated that chronic diseases, antibiotic use and having an endoscopy were significantly associated with developing IBS. Male sex and chronic diseases were significantly associated with H. pylori infection. Logistic regression analysis showed no relationship between IBS and H. Pylori infection. CONCLUSION: Chronic diseases was the only risk factor common for IBS and H. pylori infection.

Changes in intestinal microbiota and biochemical parameters in patients with inflammatory bowel disease and irritable bowel syndrome induced by the prolonged addition of soluble fibers to usual drug therapy.

OBJECTIVES: Partially hydrolyzed guar gum (PHGG) is a soluble dietary fiber;in addition to improving bowel movements, it maintains intestinal health by producing short-chain fatty acids. However, majority of clinical studies on PHGG have been concluded within a month and excluded usual drug therapy. Hence, this study aimed to determine the effects of long-term consumption of PHGG, in combination with drug therapy, on gut bacteria ratios, laboratory values for inflammatory response, and fecal characteristics. METHODS AND RESULTS: The study was performed in patients with irritable bowel syndrome (IBS), Crohn's disease (CD), and ulcerative colitis (UC), by the administration of PHGG for six months while they continued their usual treatment. PHGG treatment caused significant changes in patients with IBS, including an increase in the abundance of short-chain fatty acid-producing bacteria, a significant decrease in Bacteroides abundance, and normalization of the Bristol scale of stool. In patients with UC, non-significant normalization of soft stools and decrease in fecal calprotectin were observed. Adverse events were not observed in any of the groups. CONCLUSION: Thus, it would be beneficial to include PHGG in the usual drug therapies of patients with IBS. J. Med. Invest. 71 : 121-128, February, 2024.

Metabolome-associated psychological comorbidities improvement in irritable bowel syndrome patients receiving a probiotic.

Our recent randomized, placebo-controlled study in Irritable Bowel Syndrome (IBS) patients with diarrhea or alternating bowel habits showed that the probiotic Bifidobacterium longum (BL) NCC3001 improves depression scores and decreases brain emotional reactivity. However, the involved metabolic pathways remain unclear. This analysis aimed to investigate the biochemical pathways underlying the beneficial effects of BL NCC3001 using metabolomic profiling. Patients received probiotic (1x 1010CFU, n=16) or placebo (n=19) daily for 6 weeks. Anxiety and depression were measured using the Hospital Anxiety and Depression Scale. Brain activity in response to negative emotional stimuli was assessed by functional Magnetic Resonance Imaging. Probiotic fecal abundance was quantified by qPCR. Quantitative measurement of specific panels of plasma host-microbial metabolites was performed by mass spectrometry-based metabolomics. Probiotic abundance in feces was associated with improvements in anxiety and depression scores, and a decrease in amygdala activation. The probiotic treatment increased the levels of butyric acid, tryptophan, N-acetyl tryptophan, glycine-conjugated bile acids, and free fatty acids. Butyric acid concentration correlated with lower anxiety and depression scores, and decreased amygdala activation. Furthermore, butyric acid concentration correlated with the probiotic abundance in feces. In patients with non-constipation IBS, improvements in psychological comorbidities and brain emotional reactivity were associated with an increased abundance of BL NCC3001 in feces and specific plasma metabolites, mainly butyric acid. These findings suggest the importance of a probiotic to thrive in the gut and highlight butyric acid as a potential biochemical marker linking microbial metabolism with beneficial effects on the gut-brain axis.

A systematic review of the association between environmental risk factors and the development of irritable bowel syndrome.

BACKGROUND AND AIM: Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with roots in genetic, immune, psychological, and dietary factors. Recently, the potential correlation between environmental exposures, such as air pollution, and IBS has gained attention. This review aimed to systematically examine existing studies on environmental factors associated with IBS, elucidating this interplay and guiding future research. METHODS: A literature search was conducted in Medline, EMBASE, Scopus, and Cochrane databases from database inception to October 10, 2023, using the keywords "Irritable Bowel" or IBS or "Irritable Colon" or "Mucous Colitis" or "Spastic Colitis" or "Spastic Colon" AND "environment* exposure*". Studies were included if they were original, published in English, described defined environmental exposure(s), and had documented diagnosis of IBS. For the purposes of this review, articles reporting physical (e.g. radiation and climate change), biological (e.g. bacteria and viruses), and chemical (e.g. harmful gases) exposures were included while psychological and dietary factors, which have been reviewed in detail elsewhere, are outside of the scope. RESULTS: A total of seven studies focusing on air quality, microbial exposure, and other environmental factors were reviewed. Studies highlighted a potential association between air pollutants and increased IBS incidence. Microbial exposure, post-natural disaster or due to poor sanitation, was linked to IBS development and gut dysbiosis. Other exposures, such as early pet ownership, were also associated with IBS risk. CONCLUSION: Existing research demonstrates an epidemiologic relationship between environmental exposures and the development of IBS. Further research is needed to understand these associations.

Real-world outcomes for a digital prescription mobile application for adults with irritable bowel syndrome.

BACKGROUND: Mahana™ IBS is a Food and Drug Administration-cleared prescription mobile application designed to deliver 3 months of gut-directed cognitive behavioral therapy (CBT) to adults ≥22 years old with irritable bowel syndrome (IBS). We assessed whether gut-directed CBT delivered digitally improved outcomes in IBS management. METHODS: We studied users who had a dispensed physician prescription for Mahana™ IBS between August 2021 and August 2023. The primary outcome was change in IBS symptom severity (IBS-SSS) score. KEY RESULTS: For the 843 patients, 324 (38%) completed half of the program up to session 5, and 162 (19%) of participants completed the full program up to session 10. Median age was 41 years, median IBS-SSS was 270 (moderate severity), IBS-mixed subtype was most common (23%) followed by IBS-C (20%) and IBS-D (19%). The change in IBS-SSS was -81.0 (p = < 0.001) after session 5 and - 104.4 (p = < 0.001) after session 10. In multivariate analyses, a higher baseline IBS-SSS (OR 1.59; 95% CI 1.26-2.01) and high baseline Perceived Stress Scale (PSS) score predicted non-response (OR 0.95; 95% CI 0.91-0.98) while older age (OR 1.10 per decade; 95% CI 1.01-1.20), prescription source from a healthcare provider (as opposed to third party telehealth encounter, OR 1.48; 95% CI 1.07-2.05), and payment for the app (OR 1.93; 95% CI 1.41-2.63) predicted adherence. CONCLUSIONS & INFERENCES: Use of a digital mobile application for gut-directed CBT improved symptoms of IBS. Digital health applications have the potential to democratize CBT and allow integrated care to scale for patients with IBS.