JGH Open. 2026 Sep 7;10(9):e70467. doi: 10.1002/jgh3.70467. eCollection 2026 Sep.

ABSTRACT

AIMS: The impact of teaching patients with irritable bowel syndrome (IBS) a FODMAP diet on eating behaviors is unknown. We aimed to ascertain disordered eating behaviors and their relationships to current dietary intake and clinical status many years after FODMAP education.

METHODS AND RESULTS: Patients with IBS educated on a FODMAP diet by a gastrointestinal dietitian mean 7.1 (range 2.5-13.4) years prior were cross-sectionally evaluated for current eating behaviors utilizing multiple risk tools, mental health (Depression Anxiety Stress Scales), gastrointestinal symptoms (IBS-SSS), overall, food-related quality of life and dietary intake (Complete Nutritional Assessment Questionnaire), and retrospective analysis of documented mental health conditions. Of 74 participants (84% women, median age 59 (IQR 47-67) years), disordered eating behaviors were identified in 38% by the risk tools comprising Eating Attitudes Test (EAT)-26 in 7%, Nine Item ARFID screen (NIAS) in 24%, ORTO-7 for orthorexia in 21%. While these behaviors were associated with reduced overall and food-related quality of life, multivariable regression analyses identified only psychological distress and symptom severity as independent predictors of ARFID and orthorexia risk. Self-perceived eating pattern (strict low-FODMAP, personalized-FODMAP or habitual diets), level of measured FODMAP intake, or time since dietary education were not related to disordered eating behaviors. No new diagnoses or exacerbation of eating disorders were observed since dietary education.

CONCLUSION: Disordered eating behaviors are commonly present in long-term follow-up of patients with IBS after FODMAP dietary education, but these are related to psychological distress and symptom burden, not to specific dietary effects associated with such education.

PMID:42712718 | PMC:PMC13550526 | DOI:10.1002/jgh3.70467

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Gastroenterol Hepatol (N Y). 2026 Jul;22(7):362-370.

ABSTRACT

Sleep plays a critical role in maintaining good physical and emotional health. Sleep and circadian rhythms are fundamental regulators of human physiology, influencing most biological processes from the cellular to the organ-system level. Sleep disorders are common with a prevalence of 30% in adults. Impaired sleep reduces patients' quality of life and has a significant negative economic impact on the health care system. Sleep deprivation can affect the brain and alter normal circadian rhythms. These disturbances influence the brain-gut axis and subsequently affect both symptom development and symptom expression in patients with disorders of gut-brain interaction (DGBIs), including functional dyspepsia and irritable bowel syndrome. DGBIs are highly prevalent with at least 40% of adults worldwide meeting criteria for at least 1 DGBI. This article reviews the prevalence and impact of disordered sleep, discusses the basics of normal and abnormal sleep, examines the role of diagnostic testing for sleep disorders, and evaluates the role of disordered sleep in common DGBIs. Practical tips to evaluate and treat patients with DGBIs and disordered sleep are also discussed.

PMID:42713435 | PMC:PMC13552402

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TOPLINE

Among people with irritable bowel syndrome (IBS), more than half of those receiving fiber supplementation achieved a clinical response compared with 44% of those receiving placebo. Psyllium was associated with a greater clinical response than control.

METHODOLOGY

• Fiber supplements are often recommended as a first-line treatment for IBS, along with lifestyle changes and medications for specific symptoms, and patients usually find this treatment acceptable.

• Researchers conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the efficacy of fiber supplements vs placebo in adults with IBS. Eligible trials were conducted in community or outpatient settings.

• A total of 30 RCTs, including 1904 adults, were identified; 28 RCTs were included in the meta-analysis.

• Fiber types included wheat bran (n = 7), psyllium (n = 6), inulin-type fructans (n = 5), beta-galacto-oligosaccharides (n = 2), and various other fibers. Fiber supplements incorporated into foods were also considered. Treatment durations ranged from 7 days to 3 months, with fiber doses ranging from 1.4 to 30 g/d.

• The primary outcome was clinical response to fiber supplements; secondary outcomes were the effects of fiber supplements on gastrointestinal symptoms, stool frequency and consistency, and quality of life.

TAKEAWAY

• Clinical response occurred in 52% of participants receiving fiber vs 44% receiving placebo-like control (risk ratio [RR], 1.21; P = .02; I² = 38%; 16 trials). Psyllium was associated with a greater clinical response than control (RR, 1.53; P = .02; I² = 54%). Wheat bran did not result in a greater or worse clinical response.

• Fiber supplementation was associated with better clinical response than control in subgroup analyses of trials using doses ≤ 10 g/d (RR, 1.29; P = .04), as well as when provided as a supplement (RR, 1.23; P = .02) or in powder or granule form (RR, 1.23; P = .02).

• Beta-galacto-oligosaccharides were associated with improved overall gastrointestinal symptoms compared with control (standardized mean difference [SMD], -0.62; P = .02). Fiber given as powder or granules also showed an improvement in symptoms (SMD, -0.33; P = .02).

• There was no effect of fiber supplementation on bloating, abdominal pain, flatulence, or quality of life compared to controls. None of the reported common adverse events were attributed to fiber.

IN PRACTICE

"The findings of this systematic review and meta-analysis indicate the efficacy of fiber supplementation in relation to clinical response in IBS. Although overall and symptom-specific effects were limited, the greater global clinical response compared with placebo, particularly with psyllium, supports the continued recommendation of fiber as a first-line therapy for IBS," the authors wrote.

SOURCE

The study was led by Heidi M. Staudacher, PhD, School of Translational Medicine, Monash University, Melbourne, Australia. It was published online on August 14 in Gastroenterology.

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ABSTRACT

BACKGROUND: Irritable bowel syndrome with constipation (IBS-C) is a common disorder of gut-brain interaction that significantly impairs quality of life. Although multiple US Food and Drug Administration (FDA)-approved medications have demonstrated efficacy in randomized controlled trials, less is known about patients' real-world experiences and factors influencing treatment decisions. Here, we conducted social media netnography-a qualitative approach for examining patient perspectives posted online on social media platforms and e-health forums, exploring the perspectives and experiences of IBS-C patients who report using FDA-approved therapies.

METHODS: We examined publicly available posts from X and online health e-forums (Reddit, WebMD, ibspatient.org) made between 9/19/2007 and 9/12/2024. Overall, 7328 relevant posts referencing FDA-approved IBS-C medications (linaclotide, lubiprostone, plecanatide, tegaserod, tenapanor) were included. We employed qualitative (open coding) and quantitative approaches (natural language processing and artificial intelligence) to analyze the posts.

RESULTS: Four major themes emerged: (i) perceived medication efficacy; (ii) treatment-related burden; (iii) intentional non-adherence; and (iv) barriers to adherence. Patients described heterogeneous efficacy, ranging from meaningful symptom relief to limited or no benefit. Patients discussed the biopsychosocial burden of IBS-C medications (e.g., nausea, frustration, social anxiety from potential diarrheal side effects), highlighting various barriers to adherence. Barriers such as cost, insurance coverage, and personal beliefs also influenced decisions, often prompting discontinuation, dose adjustments, or pursuit of alternative therapies.

CONCLUSIONS: Social media provides unique insights into IBS-C patients' real-world experiences with FDA-approved therapies. Findings highlight variability in efficacy, biopsychosocial impacts, and adherence challenges, underscoring the need for shared decision making and proactive management of barriers to optimize outcomes.

Key Points

• Qualitative analysis of 7328 social media and e-forum posts captured candid, real-world perspectives from patients with IBS-C, revealing variability in perceived medication efficacy, treatment-related burden, intentional non-adherence, and barriers to adherence.

• NLP and AI methods demonstrated that the large language model reliably classified patient posts, achieving performance comparable to human annotators and supporting its use for larger-scale analyses of patient experiences.

• Given the complexity of patients' treatment experiences, these findings underscore the importance of shared decision-making and proactive management of treatment barriers to support personalized care and improved patient outcomes.

PMID:42694017 | DOI:10.1111/nmo.70432

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Front Med (Lausanne). 2026 Aug 18;13:1900112. doi: 10.3389/fmed.2026.1900112. eCollection 2026.

ABSTRACT

INRODUCTION: Evidence for probiotics in irritable bowel syndrome remains heterogeneous, although real-world use is common in Chinese gastroenterology practice. This study evaluated whether initiation of multi-strain probiotics, compared with contemporary standard care without probiotics, was associated with clinically meaningful symptom and quality-of-life improvement in adults with diarrhoea-predominant or mixed irritable bowel syndrome.

METHODS: This single-centre retrospective real-world cohort study identified adults with Rome IV IBS-D or IBS-M managed between January 2022 and December 2024 from electronic health records. A new-user design with a symmetrical 14-day landmark was used. After prespecified exclusions, 287 patients comprised the full analytic set, including 122 probiotic initiators and 165 non-users. One-to-one nearest-neighbour propensity score matching yielded 75 matched pairs. Outcomes were assessed at 4-6 and 8-12 weeks, with change in IBS Symptom Severity Score from baseline to 8-12 weeks as the primary endpoint.

RESULTS: In the matched cohort, probiotic initiation was associated with a greater reduction in IBS-SSS than standard care at 8-12 weeks, with mean changes of -95 versus -60 points and a mean difference of -35 points (95% CI: -50 to -20; p = 0.001). IBS-SSS response occurred more frequently with probiotics than with non-use (62.7% versus 44.0%), as did pain response (58.7% versus 40.0%) and adequate relief (54.7% versus 38.7%). IBS-QOL improved by 16.0 versus 8.0 points, and IBS-QOL minimal clinically important difference response was more frequent with probiotics (53.3% versus 34.7%). Adverse events were infrequent and similar between groups (16.0% versus 13.3%). Treatment escalation occurred less often with probiotics (24.0% versus 40.0%).

DISCUSSION: In routine Chinese hospital care, initiation of multi-strain probiotics was associated with earlier and clinically meaningful symptom improvement, better disease-specific quality of life, and fewer treatment escalations among adults with IBS-D or IBS-M, without an apparent excess of adverse events.

PMID:42682476 | PMC:PMC13529527 | DOI:10.3389/fmed.2026.1900112

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Mayo Clinic researchers have discovered that chemical signals produced by gut bacteria work together to control intestinal movement. One bacterial signal helps set the intestines in motion, while another primes gut cells to respond more strongly, amplifying the effect.

The research expands scientists' understanding of how the gut microbiome communicates with the body, moving beyond the traditional focus on individual bacteria or bacterial molecules.

The findings, published in the Proceedings of the National Academy of Sciences, point to a potential new direction for microbiome-based treatments: restoring combinations of microbial signals rather than targeting a single microbe or molecule. The strategy could have implications for constipation-predominant irritable bowel syndrome, a chronic condition marked by abdominal pain and constipation.

"The gut microbiome is made up of trillions of microbes producing a vast array of chemical messages that interact with cells throughout the digestive tract," says Purna Kashyap, M.B.B.S., a Mayo Clinic gastroenterologist, director of the Mayo Clinic Microbiomics Program and a senior author of the study. "Deciphering how those signals work in combination gives us a much more precise picture of what is disrupted in disease and what would need to be restored to recover normal function."

How bacterial signals work in combination

Researchers focused on two bacterial molecules: hypoxanthine and butyrate. Earlier Mayo Clinic research found lower levels of both in patients with constipation-predominant irritable bowel syndrome. That finding led researchers to a deeper question: How do these molecules affect intestinal movement?

In the new study, the researchers found that hypoxanthine prompts specialized cells lining the intestine to release serotonin, a chemical messenger that helps move food through the digestive tract. Butyrate works differently. It primes the cells to respond more strongly to hypoxanthine, amplifying the effect.

These specialized cells, called enterochromaffin cells, serve as hubs where different microbial signals come together. They help the gut receive and respond to multiple chemical messages at once.

Researchers followed that chain of events from what happens inside a single gut cell to how contents move through the intestines. They used laboratory-grown intestinal cells, miniature gut models called organoids, intestinal tissue and genetically altered bacteria to piece together each part of the process.

Gianrico Farrugia, M.D., president and CEO of Mayo Clinic and a co-author of the study, is a gastroenterologist whose research has focused on the mechanisms that control gastrointestinal function.

"We have an opportunity to move beyond managing the consequences of disease and toward restoring function for patients," Dr. Farrugia says. "That starts with answering the unanswered questions we see in our patients and following the biology until we understand the mechanism. With that depth of understanding, we can uncover new possibilities for treatment and ultimately advance new cures."

What's next 

Researchers next want to determine whether identifying combinations of microbial signals that are altered in individual patients could eventually help guide treatment. Future research will explore whether restoring complementary signals can improve intestinal movement, with the longer-term goal of developing more precisely targeted microbiome-based therapies.

The research was supported by the National Institutes of Health, Mayo Clinic Center for Individualized Medicine, Mayo Clinic Microbiome Program and other organizations. One or more of the investigators is an inventor of technology related to this research. For a complete list of authors, disclosures and funding, review the study.

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Almost everyone experiences the occasional bout of constipation. But some people feel backed up more frequently than others, whether that’s because of an existing gastrointestinal disorder, taking certain medications, or age. That’s right—you’re more likely to feel constipated as you get older. So here, we’re taking a look at why constipation becomes more common after 50.

“Constipation becomes more common with age, although getting older does not automatically mean getting constipated,” says Douglas Weine, M.D., a gastroenterologist at Red Bank Gastroenterology in Red Bank, N.J. Instead, there are certain situations that are more common in people over 50 than in younger folks that make constipation more likely to occur.

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Dig Dis Sci. 2026 Aug 28. doi: 10.1007/s10620-026-10190-7. Online ahead of print.

ABSTRACT

BACKGROUND: Recent evidence suggests an increased prevalence of irritable bowel syndrome (IBS) among individuals with allergic diseases, and several biological mechanisms have been proposed. This study aims to investigate the association between IBS and allergic diseases in a large nationwide cohort of adolescents.

METHODS: This cross-sectional nationwide study included Israeli adolescents aged 16-20 years who underwent medical assessment before military service. The military database was used to identify individuals with allergic diseases (asthma, allergic rhinitis, atopic dermatitis, or ocular atopic disease) and IBS between 1998 and 2018. Logistic regression models adjusted for sociodemographic factors were applied.

RESULTS: Of the 1,538,864 adolescents (42% women; mean age, 17.2 ± 0.5 years) included in the study, 189,806 (12.3%) were diagnosed with allergic diseases and 8,134 (0.5%) with IBS. Overall, 25.4% of adolescents with IBS had at least one concurrent allergic disease. The prevalence of IBS among adolescents with allergic diseases was 1.1%, corresponding to an adjusted OR of 2.2 (95% CI 2.1-2.4). This association remained consistent across socioeconomic groups and across all allergic diseases examined.

CONCLUSION: Allergic diseases in adolescents are associated with higher rates of concurrent IBS. These findings strengthen existing epidemiological evidence linking IBS and allergic diseases in adolescents and warrant further mechanistic and longitudinal studies.

PMID:42661130 | DOI:10.1007/s10620-026-10190-7

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Antibiotics (Basel). 2026 Aug 11;15(8):772. doi: 10.3390/antibiotics15080772.

ABSTRACT

The intricate interplay between the gut microbiome and the enteric nervous system remains a paramount focus in understanding the multifactorial pathogenesis of disorders of gut-brain interaction (DGBI), most notably irritable bowel syndrome (IBS). While the clinical entity of post-infectious IBS is well-established, the independent, long-term pathophysiological impact of iatrogenic antibiotic exposure is garnering critical attention within neurogastroenterology. This narrative review provides a comprehensive synthesis of current epidemiological and mechanistic evidence positioning antibiotic-induced microbial depletion as a potential predisposing factor for incident IBS. By evaluating recent literature, we highlight epidemiological trends demonstrating a consistent, dose-dependent relationship between cumulative antibiotic courses, particularly broad-spectrum agents, and an elevated risk of developing IBS, independent of prior acute enteric infections. Furthermore, we explore the mechanistic underpinnings of this association, focusing on how systemic antibiotics induce persistent, detrimental alterations in commensal diversity. This resulting dysbiosis initiates a proposed cascade of downstream consequences, including compromised epithelial barrier integrity, persistent low-grade mucosal inflammation, and altered bile acid metabolism. These localized disruptions serve as established triggers for visceral hypersensitivity and dysregulated gastrointestinal motility communicated via the gut-brain axis. Ultimately, this review underscores that antibiotic exposure may act as a significant, modifiable risk factor for IBS pathogenesis. Recognizing this substantial iatrogenic risk reinforces an urgent clinical imperative for stringent antimicrobial stewardship and emphasizes the necessity for future research directed toward prophylactic, microbiome-sparing strategies to mitigate the escalating global burden of DGBIs.

PMID:42650697 | DOI:10.3390/antibiotics15080772

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World J Methodol. 2026 Sep 20;16(3):118399. doi: 10.5662/wjm.118399. eCollection 2026 Sep 20.

ABSTRACT

Constipation is a common multifactorial gastrointestinal disorder with a significant impact on quality of life, healthcare utilization, and economic burden. It encompasses a spectrum of symptoms, including infrequent bowel movements (fewer than three per week), lumpy or hard stools (Bristol Stool Form Scale 1 or 2), straining, difficult stool passage, a sense of incomplete evacuation, etc. When no organic cause is identifiable, the condition is labeled as functional constipation. Pharmacological management of constipation has been extensively explored, with several new therapies added to the armamentarium in the last decade. However, its management remains challenging due to heterogeneous etiologies, varied diagnostic approaches, and the broad spectrum of therapeutic options. This narrative review summarizes contemporary strategies for the management of constipation, encompassing lifestyle and dietary modifications, pharmacological therapies, behavioral interventions, and surgical options for refractory cases. Traditional laxatives continue to form the mainstay of treatment, but newer agents such as prosecretory drugs, serotonergic agonists, and bile acid modulators have expanded therapeutic possibilities, offering targeted mechanisms and improved tolerability. Non-pharmacological approaches, including biofeedback for pelvic floor dysfunction and neuromodulation techniques, provide effective alternatives in selected patients. Despite these advances, substantial methodological variability exists in clinical trials, including differences in diagnostic criteria, endpoints, and follow-up durations, limiting the generalizability of findings. A more standardized framework for defining outcomes and assessing long-term efficacy is needed to strengthen evidence-based practice. Ultimately, the management of constipation requires an individualized approach that integrates symptom severity, underlying pathophysiology, patient preference, and availability of resources. Newer research is focused on tailoring treatment to special groups of patients with refractory constipation, surgical modalities for patients with neurogenic bowel, and microbiome modulation using artificial intelligence.

PMID:42626238 | PMC:PMC13491131 | DOI:10.5662/wjm.118399

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Irritable bowel syndrome with constipation (IBS-C) causes recurrent abdominal pain and

altered bowel habits, with substantial impacts on health-related quality of life (HRQOL) and

healthcare utilization.

Although multiple pharmacologic therapies are available, treatment

benefit seen in routine practice may differ from outcomes observed in randomized controlled

trials, and patient dissatisfaction can remain unrecognized during clinical encounters. Existing

patient-reported outcome measures provide detailed assessments on symptom severity and

treatment satisfaction but are often too lengthy and burdensome for routine use.4 A single-item

assessment may offer a pragmatic alternative, but the best single question for capturing IBS

treatment satisfaction has not been established.5 We conducted the Joint Universal Single-item

Tool for Assessing Satisfaction and Key Metrics (Just Ask) Study to identify a single-item question

that best reflects medication satisfaction in IBS-C

PMID:42624391 | DOI:10.1016/j.cgh.2026.07.041

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Does knowing the diagnostic criteria necessarily lead to sound clinical decision-making? Not always. A recent study published in Neurogastroenterology & Motility evaluated medical students from 14 Latin American countries, including Brazil, and found that although most were familiar with the Rome Criteria for disorders of gut-brain interaction (DGBI), many still relied on a diagnosis of exclusion rather than a positive diagnosis. Researchers at the University of Miami in Miami found that this approach persisted even among students who had received formal training in DGBI.

DGBI is characterized by gastrointestinal symptoms related to combinations of altered motility, visceral hypersensitivity, and changes in mucosal function, gut microbiota, or central nervous system processing.

The Rome Criteria are an international consensus framework developed by the Rome Foundation, with inputs from more than 140 experts from 27 countries. They used clinical symptoms to support a positive diagnosis without requiring extensive testing to exclude other diseases.

Article Key Points

• Rome Criteria support positive IBS dx; extensive routine testing rarely changes diagnosis.

• 238 Latin American students: 74% DGBI teaching, 69% knew Rome Criteria.

• Despite no warning signs, 70% ordered initial tests; 53% still tested after normal labs.

• ~1/3 misclassified functional symptoms as warning signs; knowledge ≠ clinical reasoning.

• Limited initial workup: CBC, CRP, celiac serology; calprotectin/colonoscopy if indicated.

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Differentiating inflammatory bowel disease (IBD) from other conditions, such as irritable bowel syndrome (IBS), can be challenging, particularly when symptoms are intermittent or mild. Careful assessment of alarm features, inflammatory markers, stool testing, and recent infectious or travel history can help identify patients who require gastroenterology (GI) evaluation. 

Since IBS lacks certain inflammatory markers that may indicate a diagnosis of IBD, understanding the patient’s medical history, their symptoms, and using the correct testing early on is crucial.

Although IBD is most commonly diagnosed between 15 and 30 years of age and in older adults as well, it can present at any age and significantly impact quality of life. Studies show that early recognition and timely diagnosis are important because persistent intestinal inflammation can lead to progressive bowel damage and complications, including strictures, fistulas, abscesses, hospitalization, and surgery. Prompt referral allows earlier initiation of appropriate therapy and may improve long-term outcomes.   

IBD red flags for primary care providers

Symptoms to watch for include:

• Persistent diarrhea over four weeks

• Blood or mucus in stool 

• Waking up during the night to have a bowel movement (Nocturnal bowel movements)

• Unintentional weight loss 

• Tenesmus (incomplete evacuation) or urgency

• Persistent abdominal pain

• Iron-deficiency anemia

• Fever or elevated inflammatory markers

• Perianal fistula, abscess, drainage

• Extraintestinal manifestations (arthritis, uveitis, erythema nodosum, pyoderma gangrenosum, and recurrent oral ulcers)

“Unlike ulcerative colitis (UC), Crohn’s disease (CD) sometimes may lack visible rectal bleeding, but consider it if there is weight loss, anemia, abdominal pain, and chronic diarrhea,” says gastroenterologist and IBD specialist Jalpa Devi, MBBS. “Extraintestinal features like arthritis, rash, recurrent oral ulcers, uveitis or scleritis, and a family history of IBD should further increase suspicion.”

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In patients with functional constipation unresponsive to first-line treatment, elobixibat provided better bowel movement response, greater symptom relief, and improved quality of life compared with prucalopride. These findings suggest elobixibat may be a more effective option for patients with treatment-refractory functional constipation. The study was published in the journal of Alimentary Pharmacology and Therapeutics by Omesh G. and colleagues.

A comparison of the efficacy and safety of elobixibat and prucalopride was conducted by conducting a multicentre prospective pragmatic trial, which employed blinding of the outcome assessor. The participants recruited for the study were adults suffering from FC, based on the Rome IV criteria, who had failed to respond adequately or were resistant to first line laxative therapies.

After a standard run-in period to define their bowel movements, the patients were randomly assigned to either elobixibat or prucalopride therapy for eight consecutive weeks. The primary end point of the study was the attainment of a sustained CSBM response, which was defined as having at least three CSBMs per week with a difference of one additional CSBM above the baseline level for six out of the eight weeks of treatment.

Key findings:

• This clinical trial included a total of 214 patients (elobixibat, n = 108; prucalopride, n = 106) having an average age of 50.8 ± 17.4 years with 62.6% of males.

• The sustained CSBM response rate was statistically more prominent in case of elobixibat (55.6%) compared to prucalopride (33.9%; p = 0.024), indicating a clear superiority.

• Although both of the medicines were effective in increasing the frequency of the bowel movements and improving the consistency of the stools, there were some statistical advantages in terms of burden reduction for the case of elobixibat (straining, p < 0.001; abdominal discomfort, p = 0.005; abdominal bloating, p = 0.011).

• The increase in the QoL score among patients under the use of elobixibat was statistically greater (p = 0.009) than that of patients under prucalopride.

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Constipation is a well-known problem for astronauts in space, and researchers now think they know why it occurs. 

Weightlessness appears to affect the gut microbiome, the billions of healthy bacteria that reside in a person’s digestive tract, researchers reported recently in Nature Communications.

"We see changes in astronauts’ blood samples that indicate that the gut bacteria begin to ferment protein to a greater extent than usual within weeks after the astronauts arrive in space, and this change continues until they are back on Earth," co-lead researcher Giorgia La Barbera said in a news release. She is an associate professors of nutrition, exercise and sports at the University of Copenhagen in Denmark. 

Protein fermentation happens when gut bacteria break down protein instead of fiber because the fiber in a person’s diet has been used up, researchers said.

"The lack of gravity in space probably causes food to move more slowly through the intestine, and this fits with the fact that we are seeing signs of increased protein fermentation," co-researcher Henrik Roager, also an associate professor of nutrition, exercise and sports at the university, said in a news release. "This may also help explain constipation in astronauts."

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J Gastroenterol Hepatol. 2026 Aug 18. doi: 10.1111/jgh.70669. Online ahead of print.

ABSTRACT

BACKGROUND: Irritable bowel syndrome with constipation (IBS-C) and diarrhea (IBS-D) exhibit highly divergent clinical manifestations. This study aims to investigate the correlation between IBS-C and IBS-D.

METHODS: All participants provided fecal samples and completed IBS-SSS, IBS-QOL, and GSRS. Fecal bacterial composition was analyzed via custom V4-region 16S rRNA amplicon sequencing on the Illumina NovaSeq 6000 platform, while bile acids were quantified using liquid chromatography-tandem mass spectrometry (LC-MS).

KEY RESULTS: Patients with IBS-D reported significantly higher frequency and severity of diarrhea and abdominal pain. Conversely, IBS-C patients experienced more severe bloating and constipation than IBS-D patients. Compared to HCs, total bile acids, primary bile acids, secondary bile acids, conjugated bile acids, and unconjugated bile acids were elevated in IBS-D but reduced in IBS-C. The gut microbiota composition of both IBS-D and IBS-C patients differed significantly from that of HCs. Differential species in the IBS-D group were primarily associated with Prevotella and Ruminococcaceae, those in the IBS-C group were mainly concentrated in Bacteroides and Clostridium, and differential species in the HCs group were primarily found in Ruminococcus. Abundances of Clostridiaceae and Bacteroides correlated negatively with plasma chenodeoxycholic acid and cholic acid, respectively, while Clostridium correlated negatively with ursodeoxycholic acid (UDCA). Ruminococcus correlated positively with isodeoxycholic acid.

CONCLUSIONS: Alterations in the bile acid-gut microbiota axis are closely related to the distinct clinical presentations of IBS-C and IBS-D. IBS-D is characterized by a decreased abundance of Ruminococcus and Clostridium, alongside increased bile acid secretion and reduced reabsorption, which primarily contribute to the observed differences.

PMID:42613095 | DOI:10.1111/jgh.70669

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It’s not a coincidence that countless people suffer from constipation and the majority of adults don’t get enough fiber in their diets. But can eating more fiber actually make constipation worse? While it seems like the answer should be no, it’s not quite that simple.

“Not getting enough fiber can contribute to constipation. Fiber helps increase stool bulk and, depending on the type of fiber, can help stool retain water and become easier to pass,” explains Augustine Tawadros, M.D., a gastroenterologist with Middlesex Monmouth Gastroenterology in Freehold, N.J. “However, constipation is not always caused by inadequate fiber, and increasing fiber does not help everyone.”

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Curr Gastroenterol Rep. 2026 Aug 15;28(1):25. doi: 10.1007/s11894-026-01053-2.

ABSTRACT

Irritable bowel syndrome is a common disorder of gut-brain interaction characterized by chronic abdominal pain and altered bowel habits in the absence of structural pathology. Its pathophysiology reflects a complex interplay between the central nervous system, enteric nervous system, microbiota, immune signaling, epithelial barrier dysfunction etc. Despite advances in the understanding of the mechanisms causing IBS, the diagnosis of IBS remains primarily symptom-based, necessitating the use of objective tools to improve diagnostic precision and personalized management. This review synthesizes highlights existing literature on IBS biomarkers, including inflammatory markers (cytokines, C-reactive protein), microbial signatures (gut microbiota composition, anti-CdtB and anti-vinculin antibodies), metabolic indicators (bile acids, short-chain fatty acids), and markers of intestinal permeability (zonulin) to assess their applications in the diagnosis and management of IBS. We also examined emerging multi-omics technologies that identify the complex patterns linking the gut, the brain and the microbiota. Early research focusing on single biomarkers demonstrated limited diagnostic utility due to the heterogeneous and multifactorial nature of IBS. Recent advances support the development of composite, mechanism-based biomarker panels that integrate multiple biological domains, offering improved representation of underlying pathophysiological processes. These developments mark a shift from a single-marker approach toward multidimensional biomarker strategies. This narrative review synthesizes current evidence and proposes a framework for integrating biomarkers into clinical practice. Biomarkers are best utilized following a positive symptom-based diagnosis and exclusion of alarm features, to stratify patients into biologically relevant subtypes and guide targeted therapy. This supports a transition from exclusion-based diagnosis of IBS towards a positive and more precise one.

PMID:42603224 | DOI:10.1007/s11894-026-01053-2

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Front Nutr. 2026 Jul 28;13:1888737. doi: 10.3389/fnut.2026.1888737. eCollection 2026.

ABSTRACT

BACKGROUND/OBJECTIVES: Running may cause gastrointestinal symptoms resembling irritable bowel syndrome (IBS). One promising and widely studied tool to alleviate these symptoms is a diet restricting fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP). The aim of the study was to assess the relationship between the frequency of consumption of foods high in FODMAPs and the frequency of IBS-like symptoms among recreational runners.

MATERIALS AND METHODS: The study included 153 recreational runners (81 women and 72 men) with a mean age of 37.8 ± 11 years. Most participants reported completing 3-4 training sessions per week (54.90%) and running 20-40 km per week (37.25%). Training intensity was not objectively assessed. Data were collected using the Computer-Assisted Web Interview method, a standardized questionnaire to assess the frequency of IBS-like symptoms, a proprietary questionnaire to assess behavioral and training factors, and food frequency questionnaire to assess the frequency of consumption of FODMAP-containing products.

RESULTS: Women scored significantly higher than men on the IBS symptom questionnaire (13.11 ± 4.82 vs. 10.71 ± 4.47; p = 0.002). Symptoms suggestive of IBS were observed more frequently among women than men (45.68% vs. 23.61%; p = 0.005). Gastrointestinal symptoms occurring during training were reported by 18.95% of all participants and were more frequent among men than women (26.39% vs. 12.35%), while post-training symptoms were reported by 12.42% of participants and were also more frequent among men than women (15.28% vs. 9.88%; overall p = 0.01). No statistically significant correlations were observed between the total FODMAP consumption frequency score and the IBS questionnaire score (r = 0.03; p = 0.76) or IBS questionnaire interpretation (r = -0.01; p = 0.89).

CONCLUSION: No significant association was observed between the frequency of consumption of FODMAP-containing products and IBS-like symptoms in this sample of amateur runners. The observed differences in symptom severity and the characteristics of training activity suggest that individual factors and gastrointestinal adaptation may play a role in the experience of symptoms. These results provide a starting point for further research that could more precisely determine the mechanisms influencing the occurrence of IBS symptoms in physically active individuals.

PMID:42582273 | PMC:PMC13457223 | DOI:10.3389/fnut.2026.1888737

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J Smooth Muscle Res. 2026;62:26-39. doi: 10.1540/jsmr.62.26.

ABSTRACT

Gastrointestinal (GI) motility follows a circadian rhythm regulated by a network of central and peripheral clocks, with the suprachiasmatic nucleus serving as the master clock. Disruptions to circadian rhythms are linked to impaired GI motility and disorders of gut-brain interaction, which include irritable bowel syndrome (IBS) and functional dyspepsia (FD). Emerging evidence suggests that circadian misalignment alters gut-brain interactions, exacerbating the symptoms of these disorders. Additionally, sex differences in circadian regulation contribute to variations in susceptibility. Indeed, women have a heightened sensitivity to circadian disruption, which may be attributed to the higher prevalence of IBS and FD among female patients. Recent studies highlight the role of molecular core clock components in regulating GI motor function. Moreover, interventions aimed at correcting circadian misalignment, such as exercise and time-restricted feeding, may help align peripheral clocks and show promise for mitigating GI motor dysfunction by restoring circadian rhythmicity, reducing stress responses, and improving sleep quality. These improvements may, in turn, alleviate symptoms of IBS and FD. We review the mechanisms linking circadian regulation to GI motility, the consequences of circadian disruption on the GI tract, and potential chronotherapeutic approaches to restoring circadian regulation. Understanding the interplay between circadian regulation and GI motility may lead to the development of novel, nonpharmacologic interventions to improve the GI motor function by optimizing circadian alignment.

PMID:42572353 | DOI:10.1540/jsmr.62.26

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The findings suggested that abdominal bloating occurring at least once each week affected almost half of patients with IBS classified using the operationalised Rome V algorithm and identified individuals with a substantially greater clinical burden. 

The researchers concluded that abdominal bloating occurring at least 1 day per week affected nearly half of patients with irritable bowel syndrome classified using the operationalised Rome V algorithm and was associated with greater symptom severity, higher psychological burden, poorer quality of life, and increased healthcare utilisation. They suggested that assessing bloating frequency may help identify patients with greater clinical burden. 

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Front Gastroenterol (Lausanne). 2026 Jul 23;5:1681818. doi: 10.3389/fgstr.2026.1681818. eCollection 2026.

ABSTRACT

BACKGROUND: IBS is a disorder of gut-brain interaction that is diagnosed positively but still requires a focused differential diagnosis and limited rule-out testing. IBS-Smart and Trio-Smart are commercially available serologic and breath tests that may alter diagnostic sequencing in clinical practice.

OBJECTIVE: To evaluate whether receipt of IBS-Smart and/or Trio-Smart was associated with differences in diagnostic resource utilization, captured diagnostic cost, chart-level diagnostic persistence, and medication use compared with contemporaneous control patients who did not receive these tests.

METHODS: This retrospective two-center cohort study included 219 adults with symptoms suggestive of IBS. Patients were grouped as IBS-Smart only (n=48), Trio-Smart only (n=43), both tests (n=11), or controls receiving neither test (n=117). Costs reflected a payer-proxy perspective in 2022 US dollars and included captured diagnostic tests and gastroenterology office visits. The archived study used propensity matching and an exploratory generalized linear model (GLM) for total diagnostic cost.

RESULTS: Colonoscopy rates were 50.0% in the IBS-Smart-only cohort, 53.5% in the Trio-Smart-only cohort, 27.3% in the combined-testing cohort, and 60.7% in controls; upper endoscopy rates were 31.3%, 41.9%, 0.0%, and 48.7%, respectively. Among patients first seen in 2018 or later, mean total captured diagnostic plus office-visit cost per patient per month was $366.85 for IBS-Smart only, $382.87 for Trio-Smart only, $361.83 for both tests, and $960.39 for controls. In the archived propensity-matched GLM, IBS-Smart testing was associated with lower total diagnostic cost (coefficient -0.22; P = 0.050), corresponding to an estimated incremental savings of $526 per patient. Stable chart-level diagnosis was observed in 79.2% of IBS-Smart-only patients, 90.7% of Trio-Smart-only patients, 72.7% of patients after IBS-Smart in the combined cohort, 90.9% after Trio-Smart in the combined cohort, and 25.6% of controls. Medication counts decreased descriptively in several tested subgroups at one year; drug-class-level aggregation could not be reconstructed reliably from the archived medication file and is therefore not overstated.

CONCLUSIONS: In this observational study, receipt of IBS-Smart and/or Trio-Smart was associated with lower captured resource utilization and greater chart-level diagnostic persistence than standard care alone. These findings should be interpreted as real-world associations rather than causal proof and do not replace Rome IV-based evaluation, alarm-feature triage, or guideline-recommended rule-out testing.

PMID:42564009 | PMC:PMC13441705 | DOI:10.3389/fgstr.2026.1681818

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Br J Nutr. 2026 Aug 3:1-28. doi: 10.1017/S0007114526108101. Online ahead of print.

ABSTRACT

Lipopolysaccharide (LPS) has been implicated in increased gut permeability and low-grade mucosal inflammation, conditions that are linked to the pathophysiology of irritable bowel syndrome (IBS). Because increased dietary fat intake can both trigger IBS symptoms and promote LPS translocation in the gut, this study aimed to better understand how a turmeric formula (TF) affects fasting and postprandial LPS response, after a high-fat challenge in patients with IBS (primary outcome). Secondary outcomes included postprandial ApolipoproteinB48 (Apo-B48) and triglycerides (TG) as markers of chylomicron-mediated LPS translocation, as well as gastrointestinal (GI) symptoms and stool pattern. In this randomized, double-blind, placebo-controlled cross-over trial, eighteen patients with IBS completed two high-fat challenge tests after 3-day supplementation with either 300 mg TF or placebo. Blood was collected in the fasting state and up to 5 hours postprandially. Data were analyzed using repeated measures mixed models. TF did not significantly alter postprandial LPS levels compared with placebo but significantly reduced postprandial Apo-B48 and TG (mean ratios 0.82 and 0.87, p=0.04 and p=0.01, respectively). Fasting LPS and TG showed a non-significant reduction after TF (mean ratios 0.79 and 0.87; both p=0.06, respectively). No differences were observed in gastrointestinal symptoms or stool characteristics. To conclude, TF did not influence dietary fat-mediated LPS translocation, but it reduced postprandial chylomicron markers, indicating a potential attenuation of chylomicron-mediated postprandial inflammation. Together with the observed trend towards reduced fasting LPS levels, these findings suggest that TF might have beneficial effects on low-grade subclinical inflammation, which could be relevant for IBS patients.

PMID:42543530 | DOI:10.1017/S0007114526108101

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J Gastroenterol Hepatol. 2026 Jul 31. doi: 10.1111/jgh.70618. Online ahead of print.

ABSTRACT

BACKGROUND AND AIM: Given the prevalence and chronicity of irritable bowel syndrome (IBS), this systematic review aimed to synthesize evidence on the cost of illness of IBS, with attention to the relative contributions of direct healthcare and indirect non-healthcare costs.

METHODS: A systematic search of PubMed, Embase, and the Cochrane Library was conducted from inception to August 2025, following PRISMA 2020 guidelines (PROSPERO CRD420251266432). Studies were included if they primarily assessed costs of IBS with sufficiently detailed methodology. Costs were inflation-adjusted to 2024 US dollars using World Bank consumer price indices and prevailing exchange rates. Risk of bias was assessed using the Consensus on Health Economic Criteria (CHEC) list.

RESULTS: Thirty-three studies met our inclusion criteria, spanning 14 countries from 1992 to 2022. Mean annual direct healthcare costs per patient ranged widely, from US$193 in Korea to US$31113 in the United States among patients with IBS-C. Among the 10 studies adopting a societal perspective, indirect costs such as absenteeism, presenteeism, and lost productivity frequently constituted a dominant share of total costs. In some settings, non-healthcare costs exceeded direct healthcare costs several-fold (e.g., Sweden: US$17112 vs. US$1943 for IBS-C). Treatment failure and inadequate symptom control were associated with higher expenditures. IBS-C incurred the highest subtype-specific costs, and racial and gender disparities in spending were identified.

CONCLUSIONS: IBS imposes a considerable global economic burden. When societal perspectives are adopted, indirect costs emerge as a predominant driver of total costs, necessitating holistic management strategies. Importantly, assessments limited to direct healthcare expenditures underestimate the true economic impact of IBS.

PMID:42538760 | DOI:10.1111/jgh.70618

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A compound in rice bran may help calm an overactive gut by reducing the calcium signals that cause intestinal muscles to contract. Ferulic acid suppressed contractions triggered by several chemical messengers in laboratory experiments. The discovery could eventually support new dietary approaches for diarrhea-related digestive disorders, although it may make constipation worse.

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