Effect of rectal distension on abdominal girth

It has been postulated that a viscerosomatic reflex activated by gut distension and inhibiting abdominal wall muscle tone may be one of the mechanisms underlying functional abdominal distension. Any demonstration of such a reflex has to take into account the fact that gut distension may increase abdominal girth as a result of volume displacement. As biomechanical and sensory rectal responses vary at different rates of rectal distension, we hypothesized that different rates of rectal distension might reveal different changes in abdominal girth. Abdominal girth was continuously recorded in 14 healthy subjects using a previously validated extensometer. The rectal distensions were made in a randomized order at rates of 100 mL min(-1) or 10 mL min(-1) up to 150 mL, and sham distensions were used as controls. An increase in abdominal girth was observed at the end of both distensions (P 相似文献   

Low-dose lactulose produces a tonic contraction in the human colon

Lactulose (10-20 g day(-1)) is used to treat constipation. At this therapeutic dose, its effects on colonic motility remain unknown. Twenty-two healthy subjects swallowed a probe with an infusion catheter, six perfused catheters and a balloon connected to a barostat. Colonic phasic and tonic motor activity was recorded in fasting state. In group 1, four volunteers ingested 15 g lactulose and motility was recorded for 5 h after entry of lactulose into the caecum; in group 2, motility was recorded during (3 h) and 2 h after intracolonic infusion of isoosmotic and isovolumetric solutions containing sodium chloride alone (n = 9) or with 15 g lactulose (n = 9). In a last group of volunteers, isotopic colonic transit after ingestion of lactulose (10 g,n = 9) was assessed and compared with a control group (n = 17). Ingestion or intracolonic infusion of 15 g lactulose significantly decreased barostat bag volume (maximal decrease: 45 +/- 12% and 35 +/- 9% of basal value respectively). Phasic contractions remained unchanged. Tonic and phasic motility was unchanged by the isotonic and isovolumetric infusion of saline. Ingestion of lactulose significantly accelerated isotopic colonic transit time compared with the control group. We conclude that in healthy humans, 10-15 g ingestion or intracaecal infusion of lactulose produces a prolonged tonic contraction that may be involved in the laxative effect of lactulose.     

A randomized controlled trial of a probiotic combination VSL# 3 and placebo in irritable bowel syndrome with bloating

AIM: To evaluate the effects of a combination probiotic on symptoms and colonic transit in patients with irritable bowel syndrome (IBS) and significant bloating. METHODS: Forty-eight patients with Rome II IBS were randomized in a parallel group, double-blind design to placebo or VSL# 3 twice daily (31 patients received 4 weeks and 17 patients 8 weeks of treatment). Pre- and post-treatment colonic transit measurements were performed using scintigraphy with (111)In charcoal. Symptoms were summarized as an average daily score for the entire period of treatment and separately for the first 4 weeks of treatment. Weekly satisfactory relief of abdominal bloating was assessed. RESULTS: Treatment with VSL# 3 was associated with reduced flatulence over the entire treatment period (placebo 39.5 +/- 2.6 vs VSL# 3 29.7 +/- 2.6, P = 0.011); similarly, during the first 4 weeks of treatment, flatulence scores were reduced (placebo 40.1 +/- 2.5 vs VSL# 3 30.8 +/- 2.5, P = 0.014). Proportions of responders for satisfactory relief of bloating, stool-related symptoms, abdominal pain and bloating scores were not different. Colonic transit was retarded with VSL# 3 relative to placebo (colon geometric center 2.27 +/- 0.20 vs 2.83 +/- 0.19, P = 0.05 respectively). CONCLUSION: VSL# 3 reduces flatulence scores and retards colonic transit without altering bowel function in patients with IBS and bloating.     

Effects of an osmotically active agent on colonic transit

It is unknown if sorbitol, a widely used laxative agent, accelerates colonic transit, and if these effects are modified by concomitant meal ingestion. Colonic transit was assessed by (111)In scintigraphy in 40 healthy subjects. After a 24-h scan, subjects received sorbitol (30 mL of 70% solution) or dextrose (30 mL of 70% solution), administered with or without a meal. Colonic transit, breath hydrogen excretion, and symptom scores were recorded for 4 h thereafter. VAS scores for flatulence, but not other symptoms increased (P = 0.004) by 13.1 +/- 6.3 mm (mean +/- SEM) on a 100 mm scale after sorbitol alone or sorbitol with a meal (by 18.9 +/- 7.2 mm), but not after dextrose. After adjusting for GC(24), sorbitol accelerated (P < 0.001) colonic transit (GC(28) = 3.0 +/- 0.3) compared with dextrose (GC(28) = 2.2 +/- 0.2), regardless of meal ingestion. Breath hydrogen excretion was correlated with the change in colonic transit (r = 0.52, P < 0.01) and with flatulence (r = 0.45, P = 0.003) after sugar ingestion. In healthy subjects, sorbitol accelerated colonic transit and increased flatulence but not other symptoms within 4 h, regardless of meal intake.     

Towards a better understanding of abdominal bloating and distension in functional gastrointestinal disorders

Abdominal bloating is an extremely common symptom affecting up to 96% of patients with functional gastrointestinal disorders and even 30% of the general population. To date bloating has often been viewed as being synonymous with an actual increase in abdominal girth, but recent evidence suggests that this is not necessarily the case. This review examines the relationship between the symptom of bloating and the physical sign of abdominal distension, as well as examining the epidemiology, pathophysiology and treatment options available for this debilitating aspect of the functional gastrointestinal disorders. Pathophysiological mechanisms explored include psychological factors, intestinal gas accumulation, fluid retention, food intolerance and malabsorption of sugars, weakness of abdominal musculature, and altered sensorimotor function. Treatment options are currently rather limited but include dietary changes, pharmacological approaches, probiotics and hypnotherapy.     

Elicitation of transient lower oesophageal sphincter relaxations in response to gastric distension and meal ingestion

The aim of this study was to compare the effect of graded gastric barostat distension and meal-induced fundic relaxation on the elicitation of transient lower oesophageal sphincter relaxation (TLOSR). In 15 healthy subjects, stepwise fundic distension and oesophageal manometry were performed simultaneously. Next, the effect of meal ingestion on proximal stomach volume and lower oesophageal sphincter function was studied. During stepwise barostat distension of the proximal stomach, a significant linear correlation between intragastric pressure (r = 0.91; P < 0.01) and the TLOSR rate during inflation and subsequent deflation (r = 0.96; P < 0.01) was found. A similar relationship was found for volume. In addition, after meal ingestion, the TLOSR rate increased significantly from 1.40 +/- 3 to 5.4 +/- 1.5 h-1 (P < 0.01) and 5.2 +/- 1.7 h-1 (P < 0.01), respectively, during the first and second 30-min postprandially. However, at similar calculated intragastric volumes, barostat distension led to a significantly higher TLOSR rate than the meal. Similarly, distension-induced increase in gastric wall tension, estimated from the measured bag pressure and volume using Laplace's law, was associated with significantly higher TLOSR rates (P < 0.01). In conclusion, the rate of TLOSRs in healthy volunteers is directly related to the degree of proximal gastric distension and pressure-controlled barostat distension is a more potent trigger of TLOSRs than a meal. The latter finding suggests that tension receptor activation is an important stimulus for TLOSRs.     

Abdominal accommodation induced by meal ingestion: differential responses to gastric and colonic volume loads

Background Using an experimental model of colonic gas infusion, we previously showed that the abdominal walls adapt to its content by an active phenomenon of abdominal accommodation. We now hypothesized that abdominal accommodation is a physiological phenomenon, and aimed to confirm that it can be induced by ingestion of a meal; a secondary aim was to determine whether the response to gut filling is region‐specific. Methods In healthy subjects (n = 24) a nutrient test meal was administered until tolerated at a rate of 50 mL min^?1. Electromyographic (EMG) activity of the anterior wall (upper and lower rectus, external and internal oblique) was measured via four pairs of surface electrodes, and EMG activity of the diaphragm via intraluminal electrodes on an esophageal tube. To address the secondary aim, the response to gastric filling was compared with that induced by colonic filling (1440 mL 30 min^?1 anal gas infusion; n = 8). Key Results Participants tolerated 927 ± 66 mL of meal (450–1500 mL). Meal ingestion induced progressive diaphragmatic relaxation (EMG reduction by 16 ± 2%; P < 0.01) and selective contraction of the upper abdominal wall (24 ± 2% increase in activity of the upper rectus and external oblique; P < 0.01 for both), with no significant changes in the lower rectus (4 ± 2%) or internal oblique (5 ± 3%). Colonic gas infusion induced a similar response, but with an overall contraction of the anterior wall. Conclusions & Inferences Meal ingestion induces a metered and region‐specific response of the abdominal walls to accommodate the volume load. Abnormal abdominal accommodation could be involved in postprandial bloating.     

Visible abdominal distension in functional gut disorders: Objective evaluation

Background

Visible abdominal distension has been attributed to: (A) distorted perception, (B) intestinal gas accumulation, or (C) abdominophrenic dyssynergia (diaphragmatic push and anterior wall relaxation).

Methods

A pool of consecutive patients with functional gut disorders and visible abdominal distension included in previous studies (n = 139) was analyzed. Patients (61 functional bloating, 74 constipation-predominant irritable bowel syndrome and 4 with alternating bowel habit) were evaluated twice, under basal conditions and during a self-reported episode of visible abdominal distension; static abdominal CT images were taken in 104 patients, and dynamic EMG recordings of the abdominal walls in 76, with diaphragmatic activity valid for analysis in 35.

Key Results

(A) Objective evidence of abdominal distension was obtained by tape measure (increase in girth in 138 of 139 patients), by CT imaging (increased abdominal perimeter in 96 of 104 patients) and by abdominal EMG (reduced activity, i.e., relaxation, in 73 of 76 patients). (B) Intestinal gas volume was within ±300 ml from the basal value in 99 patients, and above in 5 patients, who nevertheless exhibited a diaphragmatic descent. (C) Diaphragmatic contraction was detected in 34 of 35 patients by EMG (increased activity) and in 82 of 103 patients by CT (diaphragmatic descent).

Conclusions and Inferences

In most patients complaining of episodes of visible abdominal distention: (A) the subjective claim is substantiated by objective evidence; (B) an increase in intestinal gas does not justify visible abdominal distention; (C) abdominophrenic dyssynergia is consistently evidenced by dynamic EMG recording, but static CT imaging has less sensitivity.     

Characterization of sensations induced by capsaicin in the upper gastrointestinal tract

Intraluminal capsaicin induces perception in the jejunum, but chemosensitivity of proximal gastrointestinal regions is unclear. Our aim was to evaluate the quality of perception induced by intraluminal capsaicin in different regions of the upper gastrointestinal tract. Healthy volunteers received either an oral tube for distension and capsaicin perfusion of the mid-duodenum or jejunum or swallowed a capsule containing 0.75 mg capsaicin powder. Graded questionnaires evaluated quality and severity of sensations during distensions, capsaicin infusion and 30 min after ingestion of capsaicin capsules respectively. Duodenal capsaicin induced sensations at lower doses than jejunal capsaicin (P < 0.05). Most prominent sensations evoked by capsaicin infusion were pressure, cramps, pain and nausea; nausea and warmth were more intense during capsaicin infusion than distension (P < 0.05,for the duodenum and jejunum), pain was more intense during distension (P < 0.05, duodenum only). Gastric ingestion of capsaicin capsules mainly induced sensations of pressure, heartburn and warmth. Capsaicin application into the upper gastrointestinal tract reproducibly induced upper abdominal sensation. Qualitative features distinguished chemically from mechanically induced sensations, but both sensitivity for chemical and mechanical stimulation decreased along the intestine. Activation of chemical pathways could be a useful human pain model activating nociceptors apart from mechanical stimulation.     

Neurogenic pathways mediating ascending and descending reflexes at the porcine ileocolonic junction

We studied the pharmacology of the neural pathways mediating the responses of ileo‐ and coloileo‐colonic junction (ICJ) to regional distension in ten anaesthetized pigs. Using manometric pullthroughs and a sleeve sensor, we found the ICJ demonstrated sustained tone that was resistant to tetrodotoxin. Ileal distension decreased ICJ pressure by 22.2 ± 10.1% (11.9 ± 2.7–10.1 ± 2.6 mmHg; P=0.002) and colonic distension augmented ICJ pressure by 23.5 ± 8.6% (12.8 ± 1.5–15.6 ± 2.1 mmHg; P=0.02). Bethanecol and Nω‐nitro‐ L ‐arginine methyl ester ( L ‐NAME) increased ICJ pressure (P=0.002, P=0.01, respectively). Sodium nitroprusside and isoproterenol reduced ICJ pressure (P=0.004, P=0.02, respectively). In the presence of L ‐NAME, the early inhibitory ileo‐ICJ response was abolished, while early and late inhibitory responses were abolished by further addition of propranolol but not by the addition of hexamethonium, atropine, prazosin or yohimbine. The excitatory colo‐ICJ response was replaced by inhibition in the presence of L ‐NAME. We concluded that: 1 the porcine ICJ displays myogenic tone which is influenced by excitatory muscarinic and inhibitory nitrergic and beta adrenergic pathways 2 an inhibitory ileo‐sphincteric reflex mediated by nitrergic and beta adrenergic postganglionic neural pathways 3 both excitatory and inhibitory neurogenic colo‐sphincteric reflexes exist, and the excitatory pathway involves nitrergic neurotransmission.     

Influence of a 5HT1 receptor agonist on gastric accommodation and initial transpyloric flow in healthy subjects

Sumatriptan, a 5HT1 receptor agonist, inhibits antral motor activity, delays gastric emptying and relaxes the gastric fundus. The aim of this study was to characterize the effect of sumatriptan on transpyloric flow and gastric accommodation during and immediately after ingestion of a liquid meal using duplex sonography. Ten healthy subjects were investigated twice on separate days. In random order either sumatriptan 6 mg (Imigran® 0.5 mL) or a placebo were given s.c. 15 min before ingesting 500 mL of a meat soup. The subjects were examined during the 3-min period before ingestion of the liquid meal, the 3-min spent drinking the meal and 10 min postprandially. Sumatriptan caused a significant widening of both the gastric antrum (P=0.02) and the proximal stomach (P=0.01) 10 min postprandially as compared with placebo. It caused no significant differences in time to initial gastric emptying (P=0.2), but significantly delayed commencement of peristaltic-related transpyloric flow (P=0.04). Sumatriptan had no significant effect on mean abdominal symptom scores, but after sumatriptan there was a significant negative correlation between width of postprandial antral area and postprandial nausea and between width of postprandial antral area and postprandial bloating. We therefore conclude that sumatriptan causes a postprandial dilatation of both the distal and the proximal stomach with no change in dyspeptic symptoms nor in length of time to first gastric emptying. Time to commencement of peristaltic-related emptying is delayed.     

Distension technique influences the relationship between colonic and rectal hypersensitivity in irritable bowel syndrome

In irritable bowel syndrome (IBS), it remains unclear whether rectal hypersensitivity is a 'marker' of colonic hypersensitivity. Our aim was to examine the relation between colonic and rectal sensitivity in IBS patients, comprising phasic and ramp distension techniques. Twenty IBS patients and 12 healthy subjects (N) underwent stepwise ramp and random phasic barostat distensions in the colon and rectum in random order. The sensory threshold pressure (ramp distension) and the visual analogue scale score (VAS, phasic distension), for pain and non-pain, were recorded. Colonic thresholds were lower, and VAS scores were generally higher, for pain and non-pain sensitivities in IBS compared to N. Rectal thresholds were lower, and VAS scores were higher, for pain but not for non-pain, in IBS compared to N. In IBS, for phasic distension, there was good correlation between the colon and rectum for non-pain (e.g. at 16 mmHg, r=0.59, P=0.006) and pain (r=0.60, P=0.006) sensitivities. In contrast, there was no significant correlation between the colon and rectum for ramp distension. In conclusion, colonic and rectal sensitivity in IBS are correlated in response to phasic but not ramp barostat distensions. The rectum serves as a legitimate 'window' for evaluating colonic hypersensitivity in IBS, provided that phasic distensions are employed.     

Sensory signalling effects of tegaserod in patients with irritable bowel syndrome with constipation.

Tegaserod relieves overall and multiple individual constipation-predominant irritable bowel syndrome (IBS-C) symptoms. However, mechanisms for the relief of abdominal pain/discomfort are not well understood. The effects of tegaserod on rectal sensitivity to distension were measured by the nociceptive flexion RIII reflex, as evidenced by spinal hyperexcitability (i.e. increase or facilitation of the RIII reflex), in IBS-C patients. A randomized, double-blind, placebo-controlled, parallel study was performed in 30 women with IBS-C. The effects of slow ramp rectal distension on the RIII reflex, recorded from the lower limb, were measured before [first experimental day (D1)] and after 7 days [day 8 (D8)] of placebo (n=15) or 6 mg tegaserod bid (n=15). Pressure-volume and sensation-volume relationships were measured during distension, and patients reported their IBS symptoms daily. On D1, rectal distension facilitated the RIII reflex in both treatment groups. On D8 vs D1 these facilitatory effects were significantly lower (P<0.001, analysis of variance) after tegaserod (mean reduction: -30.3+/-11.9%) than placebo (mean reduction: -10.1+/-12.9%). No significant changes in the volume-sensation relationship or differences in compliance were observed with tegaserod or placebo. In conclusion, tegaserod reduces the facilitatory effects of rectal distension on the RIII reflex in women with IBS-C.     

Neural gastrointestinal electrical stimulation enhances colonic motility in a chronic canine model of delayed colonic transit

Neural gastrointestinal electrical stimulation (NGES) induces sequential contractions and enhances emptying in acute canine gastric and colonic models. This study was set to determine (i) the effect of NGES in a chronic canine model of delayed colonic transit and (ii) possible mechanism of action. Four pairs of electrodes were implanted in the distal colon of nine mongrel dogs. Delayed colonic transit was induced by diphenoxylate/atropine and alosetron. Transit was fluoroscopically determined by the rate of evacuation of radiopaque markers, and was tested twice in each dog, in random order, on and off stimulation. Two stimulation sequences, separated by 1 min, were delivered twice a day via exteriorized electrodes. Colonic manometry during stimulation was performed before and after intravenous (i.v.) injection of 1 mg of atropine. Complete evacuation of all markers was significantly shortened by NGES, from 4 days to 2 days, interquartile range 3-4 days vs 2-3 days, respectively, P = 0.016. NGES induced strong sequential contractions that were significantly diminished by atropine: 190.0 +/- 14.0 mmHg vs 48.7 +/- 19.4 mmHg, respectively (P < 0.001). NGES induces strong sequential colonic contractions and significantly accelerates movement of content in a canine model of delayed colonic transit. The effect is atropine sensitive.     

Influence of age on rectal tone and sensitivity to distension in healthy subjects

Hypersensitivity to rectal distension is frequently observed in patients with irritable bowel syndrome (IBS). However, few data are available about the influence of age on rectal sensory thresholds and tone. The aim of this study was to measure rectal sensory thresholds and tone with a barostat in 12 healthy subjects (aged 86 +/- 4 years, eight females, four males) as compared with 12 young healthy male controls (26 +/- 1 years). Isobaric phasic distensions were performed in the fasted state (increment of 4 mmHg, steps of 5 min, interval of 5 min). Rectal tone changes were then measured as changes in volume of the barostat bag, the pressure being kept constant. After a baseline recording of 1 h, a 1000-kcal meal was served and the tone recorded until return to baseline. Rectal sensory thresholds were significantly higher in aged subjects. First sensation, sensation of urge to defaecate and sensation of pain were triggered at 21.1 +/- 3.2 mmHg, 30.4 +/- 5.4 mmHg and 40.5 +/- 5.0 mmHg, respectively, in aged subjects, vs 13.3 +/- 4.6 mmHg (P < 0.05), 20.7 +/- 1.0 mmHg (P < 0.001) 31.3 +/- 1.7 mmHg (P < 0.001) in controls. Rectal compliance was not significantly different between the two groups. Mean barostat bag volume was 104 +/- 13 mL in fasting aged subjects and 125 +/- 23 mL in controls (NS). After the meal, the barostat bag volume decreased by 69 +/- 11% during 85 +/- 17 min in aged subjects and 75 +/- 14% during 89 +/- 15 min in young controls (NS). Rectal sensory thresholds triggered by distension are increased in aged healthy subjects while compliance and tone are not different. Age should be considered as a confounding factor when studying rectal sensitivity and further studies in aged patients with IBS should include a group of control subjects within the same range of age as studied patients.     

Idiopathic edema is associated with obstructive sleep apnea in women

BACKGROUND AND PURPOSE: This study was undertaken to clarify whether idiopathic edema is a marker for obstructive sleep apnea (OSA), independent of level of obesity, in patients with normal left ventricular function. PATIENTS AND METHODS: Seventy-eight ambulatory, obese, adults, 44 with bilateral, pitting pre-tibial edema, and 34 without edema, from an inner city family practice and a suburban family practice enrolled from July 1995 until March 2003. Edematous subjects, but not non-edematous subjects, underwent echocardiography, urinalysis, and blood test evaluations to ensure that cardiac, renal, hepatic, and thyroid functions were normal. All subjects underwent spirometry, pulse oximetry on room air, and polysomnography evaluations. RESULTS: Compared to the non-edematous subjects, the edematous subjects were more obese (body mass index=47.0+/-9.3 versus 36.5+/-4.6 kg/m2, P=0.002), had more severe OSA (apnea-hypopnea index (AHI)=34.1+/-27.7 versus 17.0+/-19.4, P=0.002), and had lower oxygen saturations (96.2+/-2.0 versus 97.1+/-1.5%, P=0.05). Using an AHI > or = 15 as the criteria for diagnosing OSA, there was an association between edema and OSA in women (P=0.02) but not men. CONCLUSIONS: In subjects with normal left ventricular function, idiopathic edema is associated with OSA in women.     

Effects of acute alcohol ingestion on neuromotor functions

To scrutinize the neuromotor effects of acute alcohol ingestion, postural sway, hand tremor, and reaction time were measured before and after alcohol or juice ingestion in 13 healthy volunteers at 20-22 years (mean 20.7) of age. The dose of ethanol consumed by the subjects (mean+/-S.D.) was 0.59+/-0.07 g/kg body weight, and the blood ethanol concentrations were estimated to be 0.86+/-0.23 g/l at 30 min after ethanol ingestion; 0.88+/-0.19 g/l at 70 min; 0.74+/-0.27 g/l at 130 min. The 1-h and 2-h changes in sway area, total transversal sway (Dx), and Dx at 0-1 Hz with eyes closed were significantly larger after alcohol ingestion than after juice ingestion. Similarly, the 2-h changes in sway area, total Dx, and Dx at 0-1 Hz with eyes open were significantly larger after alcohol ingestion than after juice ingestion. No significant differences were seen between alcohol and juice ingestion regarding changes in hand tremor or reaction time. These data suggest that the static balance due to acute alcohol ingestion is characterized mainly by transversal sway of low frequency (0-1 Hz) with eyes closed, which seems to differ from the characteristics of postural sway in alcoholics.     

Acute alterations of cyclo(His-Pro) levels after oral ingestion of glucose

We analyzed the response of plasma cyclo(His-Pro) (CHP) (N = 14), insulin (N = 8), and glucose (N = 8) to oral ingestion of 75 grams of glucose in normal volunteers. Mean Fasting CHP levels prior to glucose were 614 +/- 112 pg/ml (+/-SE). After glucose ingestion there occurred an acute rise of plasma CHP within 15 minutes (12/14) followed by a fall in plasma concentrations to below baseline values (11 of 14). The mean of highest levels within the first 15 minutes after glucose ingestion was 1035 +/- 300 pg/ml (+/-SE), significantly above baseline (p = 0.002). The mean of lowest values below baseline was 490 +/- 94 pg/ml (+/-SE), p less than 0.001. We conclude that levels of CHP are acutely and reversibly altered by the ingestion of glucose. The possible significance of these perturbations in CHP concentrations is discussed.     

Comparison of breath testing with fructose and high fructose corn syrups in health and IBS

Abstract  Although incomplete fructose absorption has been implicated to cause gastrointestinal symptoms, foods containing high fructose corn syrup (HFCS) contain glucose. Glucose increases fructose absorption in healthy subjects. Our hypothesis was that fructose intolerance is less prevalent after HFCS consumption compared to fructose alone in healthy subjects and irritable bowel syndrome (IBS). Breath hydrogen levels and gastrointestinal symptoms were assessed after 40 g of fructose (12% solution) prepared either in water or as HFCS, administered in double-blind randomized order on 2 days in 20 healthy subjects and 30 patients with IBS. Gastrointestinal symptoms were recorded on 100-mm Visual Analogue Scales. Breath hydrogen excretion was more frequently abnormal ( P  < 0.01) after fructose (68%) than HFCS (26%) in controls and patients. Fructose intolerance (i.e. abnormal breath test and symptoms) was more prevalent after fructose than HFCS in healthy subjects (25% vs 0%, P  = 0.002) and patients (40% vs 7%, P  = 0.062). Scores for several symptoms (e.g. bloating r  = 0.35) were correlated ( P  ≤ 0.01) to peak breath hydrogen excretion after fructose but not HFCS; in the fructose group, this association did not differ between healthy subjects and patients. Symptoms were not significantly different after fructose compared to HFCS. Fructose intolerance is more prevalent with fructose alone than with HFCS in health and in IBS. The prevalence of fructose intolerance is not significantly different between health and IBS. Current methods for identifying fructose intolerance should be modified to more closely reproduce fructose ingestion in daily life.