Effect of intragastric FODMAP infusion on upper gastrointestinal motility, gastrointestinal, and psychological symptoms in irritable bowel syndrome vs healthy controls.

BACKGROUND: The low fermentable oligo-, di-, mono-saccharides and polyol (FODMAP) diet is a treatment strategy to reduce symptoms of irritable bowel syndrome (IBS). Acute effects of FODMAPs on upper gastrointestinal motility are incompletely understood. Our objectives were to assess the acute effects of intragastric FODMAP infusions on upper gastrointestinal motility and gastrointestinal and psychological symptoms in healthy controls (HC) and IBS patients. METHODS: A high-resolution solid-state manometry probe and an infusion tube were positioned into the stomach. Fructans, fructose, FODMAP mix, or glucose was intragastrically administered to HC, and fructans or glucose was administered to IBS patients until full satiation (score 0-5), in a randomized crossover fashion. Manometric measurements continued for 3 hours. Gastrointestinal and psychological symptoms were assessed by questionnaires at predefined time points. The study was registered on www.clinicaltrials.gov (NCT02980406). KEY RESULTS: Twenty HC and 20 IBS patients were included. Fructans induced higher postprandial gastric pressures compared with glucose over both groups (P<.001). Bloating, belching, and pain increased more in IBS over both carbohydrates (P<.041). In addition, IBS patients reported more flatulence and cramps compared with HC following fructans (P<.001). Glucose induced more fatigue and dominance compared with fructans (P=.028, P=.001). Irritable bowel syndrome patients reported a higher increase in anger (P=.030) and a stronger decrease in positive affect (P=.021). CONCLUSIONS & INFERENCES: The upper gastrointestinal motility response varies between carbohydrates. Irritable bowel syndrome patients are more sensitive to fructan infusion, reflected in their higher gastrointestinal symptom scores. Acute carbohydrate infusion can have differential psychological effects in IBS and HC.

Inaccuracy of patient-reported descriptions of and satisfaction with bowel actions in irritable bowel syndrome.

BACKGROUND: Perception of diarrhea and constipation differs greatly. This study aimed to correlate subjective and objective assessment of fecal characteristics in irritable bowel syndrome (IBS) patients. METHODS: Data from two interventional dietary trials with varying FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) or gluten content were interrogated. Subjects rated their dissatisfaction with stool consistency daily using a visual analog scale during the interventions. Subjects collected stools at the end of each intervention. Each stool was scored according to the King's Stool Chart (KSC). Fecal water content (FWC) was measured on pooled feces by freeze drying, with diarrhea defined as ≥78%. KEY RESULTS: Seventy IBS (Rome III) and eight healthy subjects were studied. Each subject's self-rating of stool consistency during the most symptomatic diet was approximately double that of their least. Degree of dissatisfaction with stool consistency correlated poorly with changes in FWC and KSC. IBS subtype related poorly to objective measures of stool consistency. Sixty percent of IBS-D subjects had diarrhea on objective measures. Eighty-five percent with IBS-C had hard and formed stools but three patients met the criteria for diarrhea. One healthy subject had diarrhea on FWC and KSC, and six had hard, formed stools. No differences in FWC was observed when subjects consumed differing amounts of FODMAPs or gluten (all P > .200). CONCLUSIONS AND INFERENCES: There are major disparities between patients' stool descriptions and objective features of constipation and diarrhea. Patient-reported bowel habits require more interrogation for accurate IBS subtyping. Varying FODMAP or gluten content of the diet is not associated with consistent change in FWC.

Randomised clinical trial: gluten may cause depression in subjects with non-coeliac gluten sensitivity - an exploratory clinical study.

BACKGROUND: Current evidence suggests that many patients with self-reported non-coeliac gluten sensitivity (NCGS) retain gastrointestinal symptoms on a gluten-free diet (GFD) but continue to restrict gluten as they report 'feeling better'. AIM: To investigate the notion that a major effect of gluten in those with NCGS is on mental state and not necessarily on gastrointestinal symptoms. METHODS: Twenty-two subjects (24-62 years, five male) with irritable bowel syndrome who had coeliac disease excluded but were symptomatically controlled on a GFD, undertook a double-blind cross-over study. Participants randomly received one of three dietary challenges for 3 days, followed by a minimum 3-day washout before crossing over to the next diet. Challenge gluten-free food was supplemented with gluten (16 g/day), whey (16 g/day) or not supplemented (placebo). End-points included mental state as assessed by the Spielberger State Trait Personality Inventory (STPI), cortisol secretion and gastrointestinal symptoms. RESULTS: Gluten ingestion was associated with higher overall STPI state depression scores compared to placebo [M = 2.03, 95% CI (0.55-3.51), P = 0.010] but not whey [M = 1.48, 95% CI (-0.14 to 3.10), P = 0.07]. No differences were found for other STPI state indices or for any STPI trait measures. No difference in cortisol secretion was identified between challenges. Gastrointestinal symptoms were induced similarly across all dietary challenges. CONCLUSIONS: Short-term exposure to gluten specifically induced current feelings of depression with no effect on other indices or on emotional disposition. Gluten-specific induction of gastrointestinal symptoms was not identified. Such findings might explain why patients with non-coeliac gluten sensitivity feel better on a gluten-free diet despite the continuation of gastrointestinal symptoms.

Quantification of fructans, galacto-oligosacharides and other short-chain carbohydrates in processed grains and cereals.

BACKGROUND: Wholegrain grains and cereals contain a wide range of potentially protective factors that are relevant to gastrointestinal health. The prebiotics best studied are fructans [fructooligosaccharides (FOS), inulin] and galactooligosaccharides (GOS). These and other short-chain carbohydrates can also be poorly absorbed in the small intestine (named fermentable oligo-, di- and monosaccharides and polyols; FODMAPs) and may have important implications for the health of the gut. METHODS: In the present study, FODMAPs, including fructose in excess of glucose, FOS (nystose, kestose), GOS (raffinose, stachyose) and sugar polyols (sorbitol, mannitol), were quantified using high-performance liquid chromatography with an evaporative light scattering detector. Total fructan was quantified using an enzymic hydrolysis method. RESULTS: Fifty-five commonly consumed grains, breakfast cereals, breads, pulses and biscuits were analysed. Total fructan were the most common short-chain carbohydrate present in cereal grain products and ranged (g per portion as eaten) from 1.12 g in couscous to 0 g in rice; 0.6 g in dark rye bread to 0.07 g in spelt bread; 0.96 g in wheat-free muesli to 0.11 g in oats; and 0.81 g in muesli fruit bar to 0.05 g in potato chips. Raffinose and stachyose were most common in pulses. CONCLUSIONS: Composition tables including FODMAPs and prebiotics (FOS and GOS) that are naturally present in food will greatly assist research aimed at understanding their physiological role in the gut.