The role of diet in the pathophysiology and management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder that reportedly affects 5% to 20% of the world population. The etiology of IBS is not completely understood, but diet appears to play an important role in its pathophysiology. Asian diets differ considerably from those in Western countries, which might explain differences in the prevalence, sex, and clinical presentation seen between patients with IBS in Asian and Western countries. Dietary regimes such as a low-fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet and the modified National Institute for Health and Care Excellence (NICE) diet improve both symptoms and the quality of life in a considerable proportion of IBS patients. It has been speculated that diet is a prebiotic for the intestinal microbiota and favors the growth of certain bacteria. These bacteria ferment the dietary components, and the products of fermentation act upon intestinal stem cells to influence their differentiation into enteroendocrine cells. The resulting low density of enteroendocrine cells accompanied by low levels of certain hormones gives rise to intestinal dysmotility, visceral hypersensitivity, and abnormal secretion. This hypothesis is supported by the finding that changing to a low-FODMAP diet restores the density of GI cells to the levels in healthy subjects. These changes in gut endocrine cells caused by low-FODMAP diet are also accompanied by improvements in symptoms and the quality of life.publishedVersio

Effect of Meal Size and Test Duration on Gastric Emptying and Gastric Myoelectrical Activity as Determined with Simultaneous [13C]Octanoate Breath Test and Electrogastrography in Normal Subjects Using a Muffin Meal

Our purpose was to determine the effect of meal size on gastric emptying (GE) as measured by octanoate breath test (OBT), to determine the effect of the duration of breath collections on assessment of GE by OBT, and to determine the effect of meal size on gastric myoelectrical activity as measured by electrogastrography (EGG). Fourteen normal subjects underwent two modified [ 13 C]OBTs using muffin meals of 250 or 350 kcal mixed with 100 mg [ 13 C]sodium octanoate. T 1/2 for GE was determined for both the entire postprandial 6-hr breath collection and a truncated initial 4-hr data set. EGG was recorded for 30 min prior to the muffin meal and 4 hr postprandially. Using the 6-hr breath collection data, the T 1/2 was 177 ± 7 (mean ± sem) for the 350-kcal meal compared to 153 ± 7 min ( P < 0.01) for the 250-kcal meal. Using the 4-hr data, the T 1/2 for the 350-kcal meal was 244 ± 32 min compared to 165 ± 12 min ( P < 0.05) for the 250-kcal meal. The ratio of postprandial to fasting EGG power of the dominant frequency for the 350-kcal meal (1.9 ± 0.4) was higher than that for the 250-kcal meal (1.3 ± 0.6). T 1/2 for the 350-kcal meal using 4- and 6-hr data was significantly correlated with the 4-hr power ratio ( r = 0.68 and 0.67; P < 0.05, respectively), but poorly correlated for the 250-kcal meal. In conclusions, GE and EGG are affected by meal size. Using the muffin-based [ 13 C]OBT, T 1/2 for the 350-kcal meal was significantly longer than for a 250-kcal meal. Longer T 1/2 values were obtained with shorter breath sampling durations. The postprandial to fasting power ratio for the 350-kcal meal was greater than that for the 250-kcal meal.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44429/1/10620_2004_Article_364228.pd

Asian Motility Studies in Irritable Bowel Syndrome

Altered motility remains one of the important pathophysiologic factors in patients with irritable bowel syndrome (IBS) who commonly complain of abdominal pain and stool changes such as diarrhea and constipation. The prevalence of IBS has increased among Asian populations these days. Gastrointestinal (GI) physiology may vary between Asian and Western populations because of differences in diets, socio-cultural backgrounds, and genetic factors. The characteristics and differences of GI dysmotility in Asian IBS patients were reviewed. MEDLINE search work was performed including following terms, 'IBS,' 'motility,' 'transit time,' 'esophageal motility,' 'gastric motility,' 'small intestinal motility,' 'colonic motility,' 'anorectal function,' and 'gallbladder motility' and over 100 articles were categorized under 'esophagus,' 'stomach,' 'small intestine,' 'colon,' 'anorectum,' 'gallbladder,' 'transit,' 'motor pattern,' and 'effect of stressors.' Delayed gastric emptying, slow tansit in constipation predominant IBS patients, rapid transit in diarrhea predominant IBS patients, accelerated motility responses to various stressors such as meals, mental stress, or corticotrophin releasing hormones, and altered rectal compliance and altered rectal accomodation were reported in many Asian studies regarding IBS. Many conflicting results were found among these studies and there are still controversies to conclude these as unique features of Asian IBS patients. Multinational and multicenter studies are needed to be performed vigorously in order to elaborate characteristics as well as differences of altered motililty in Asian patients with IBS

Development, Translation and Validation of Enhanced Asian Rome III Questionnaires for Diagnosis of Functional Bowel Diseases in Major Asian Languages: A Rome Foundation-Asian Neurogastroenterology and Motility Association Working Team Report

Background/AimsThe development-processes by regional socio-cultural adaptation of an Enhanced Asian Rome III questionnaire (EAR3Q), a cultural adaptation of the Rome III diagnostic questionnaire (R3DQ), and its translation-validation in Asian languages are presented. As English is not the first language for most Asians, translation-validation of EAR3Q is essential. Hence, we aimed to culturally adapt the R3DQ to develop EAR3Q and linguistically validate it to show that the EAR3Q is able to allocate diagnosis according to Rome III criteria.MethodsAfter EAR3Q was developed by Asian experts by consensus, it was translated into Chinese, Hindi-Telugu, Indonesian, Korean, and Thai, following Rome Foundation guidelines; these were then validated on native subjects (healthy [n = 60], and patients with irritable bowel syndrome [n = 59], functional dyspepsia [n = 53] and functional constipation [n = 61]) diagnosed by clinicians using Rome III criteria, negative alarm features and investigations.ResultsExperts noted words for constipation, bloating, fullness and heartburn, posed difficulty. The English back-translated questionnaires demonstrated concordance with the original EAR3Q. Sensitivity and specificity of the questionnaires were high enough to diagnose respective functional gastrointestinal disorders (gold standard: clinical diagnoses) in most except Korean and Indonesian languages. Questionnaires often uncovered overlapping functional gastrointestinal disorders. Test-retest agreement (kappa) values of the translated questionnaires were high (0.700–1.000) except in Korean (0.300–0.500) and Indonesian (0.100–0.400) languages at the initial and 2-week follow-up visit.ConclusionsThough Chinese, Hindi and Telugu translations were performed well, Korean and Indonesian versions were not. Questionnaires often uncovered overlapping FGIDs, which were quite common

Gastroparesis and functional dyspepsia: excerpts from the AGA/ANMS meeting

Despite the relatively high prevelance of gastroparesis and functional dyspepsia, the aetiology and pathophysiology of these disorders remain incompletely understood. Similarly, the diagnostic and treatment options for these two disorders are relatively limited despite recent advances in our understanding of both disorders.This manuscript reviews the advances in the understanding of the epidemiology, pathophysiology, diagnosis, and treatment of gastroparesis and functional dyspepsia as discussed at a recent conference sponsored by the American Gastroenterological Association (AGA) and the American Neurogastroenterology and Motility Society (ANMS). Particular focus is placed on discussing unmet needs and areas for future research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78690/1/j.1365-2982.2009.01434.x.pd

Prevalence of Dyspepsia in Individuals with Gastro-Esophageal Reflux-Type Symptoms in the Community: A Systematic Review and Meta-Analysis

Background & Aims: Dyspepsia and gastro-esophageal reflux are highly prevalent in the general population, but they are believed to be separate entities. We conducted a systematic review and meta-analysis to estimate the prevalence of dyspepsia in individuals with gastro-esophageal reflux symptoms (GERS), and to quantify overlap between the disorders. Methods: We searched MEDLINE, EMBASE, and EMBASE Classic databases to identify population-based studies reporting the prevalence of dyspepsia and GERS in adults, defined using specific symptom-based criteria or based on answers to questionnaires. We calculated pooled prevalence values, according to study location and criteria used to define weekly GERS or dyspepsia, as well as odds ratios (ORs) with 95% CIs. The degree of overlap between dyspepsia and GERS was examined. Results: Of 14,132 papers evaluated, 79 reported prevalence of weekly GERS. Nineteen of these study populations, comprising 111,459 participants, also reported the proportion of individuals with dyspepsia. The prevalence of dyspepsia in individuals with weekly GERS was 43.9% (95% CI, 35.1–52.9%). The pooled OR for dyspepsia in individuals with weekly GERS, compared with those without, was 6.94 (95% CI, 4.33 to 11.1). The OR for dyspepsia in individuals with weekly GERS was significantly higher in all geographical regions studied and for all diagnostic criteria. The pooled degree of overlap between dyspepsia and GERS was 25.9% (95% CI, 19.9%–32.4%). Conclusion: The odds of dyspepsia in individuals with weekly GERS is almost 7-fold that of individuals without GERS; dyspepsia and GERS overlap in more than 25% of individuals. Reasons for this remain speculative, but might include shared pathophysiological mechanisms or residual confounding factors. However, patients with GERS should be questioned about co-existent dyspepsia, to optimize treatment approaches