Investigation into the role of cephalic stimulation of acid secretion on gastric emptying and appetite following a soup meal using the gastric acid inhibitor omeprazole.

We previously showed that oral administration of a liquid soup preload was associated with a slower rate of gastric emptying and suppressed appetite more compared with intragastric administration of the same soup [Appetite 31(1998)377]. The present study was designed to investigate whether these results could be explained by the cephalic stimulation of acid secretion induced by oral administration. Eight healthy male subjects took part in a double-blind placebo controlled study comparing the effects of omeprazole and placebo on gastric emptying, appetite ratings and subsequent food intake following the ingestion of a liquid soup. Subjects were administered with a single oral dose of 80 mg omeprazole or placebo 3 h prior to ingesting the radiolabelled soup preload (400 kcal; 425 ml) over 15 min. Ratings of hunger, desire to eat and fullness were recorded over 135 min and gastric emptying was measured by scintigraphy. Food intake was evaluated from a test meal (yoghurt drink) given 120 min after the end of the soup ingestion. Analysis of data showed that there was no significant difference between omeprazole and placebo in gastric emptying, appetite or subsequent energy intake from the test meal. The results suggest that gastric acid secretion is not responsible for the differences in gastric emptying and appetite observed between intragastrically infused and orally administered soup preloads.

Abnormal illness behaviour and locus of control in patients with functional bowel disorders.

OBJECTIVES: Psychosocial factors have been examined in functional bowel disorders (FBD), including irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC). Abnormal illness behaviour (AIB) has been investigated in IBS patients as evidence of underlying psychological distress and as influencing health-care-seeking behaviour. Health locus of control may also contribute to health-care-seeking behaviour, as possession of an external locus of control places responsibility for health status onto professionals. Thus, external locus of control may also be more prominent in FBD patients. This study examined whether FBD patients displayed more AIB and an external health locus of control compared with organic disease and non-patient controls. DESIGN: A cross-sectional comparison group design was employed. METHOD: Fifty-three CIC patients were compared with matched control groups of 50 IBS patients, 51 Crohn's disease patients and 53 non-patient participants. Questionnaire measures included the Illness Behaviour Questionnaire, the Multi-dimensional Health Locus of Control, the GHQ, and the SCL-90R. RESULTS: FBD patients did not differ from Crohn's disease patients on measures of AIB, but all three patient groups differed from non-patient participants. Crohn's disease patients possessed a higher external locus of control compared with FBD patients and non-patient controls. There was a general association between AIB and psychopathology. CONCLUSIONS: FBD patients did not report more AIB or a higher external locus of control regarding their health status, compared with organic disease controls, but did differ from non-patients. The presentation of AIB was related to increased psychopathology, suggesting that AIB may be related to psychological distress, irrespective of patient status.

Prospective study of factors influencing the persistence of symptoms in hospitalised patients with acute infection.

Sequential patients, aged 18-50, admitted to an Infectious Diseases Unit of a large teaching hospital with an acute infection, completed validated psychometric questionnaires on admission and were followed up at three monthly intervals for 12 months. 34% of patients available for follow-up remained symptomatic at 3 months, but by 6 months and for the rest of the study, only about 20% of patients available for follow-up remained symptomatic. Symptoms resembled those of the initial infection at 3 months, but for the remainder of the study, most patients complained of nonspecific symptoms of tiredness and lassitude. Patients symptomatic at 3 and 6 months (S+) had significantly higher depression scores on admission compared with nonsymptomatic group (S-) (P<.05). Stepwise logistic regression revealed that case level depression on admission was predictive of a 13-fold increase in the chance of remaining symptomatic at 6 months. These associations were lost by 12 months. In conclusion, this study has supported the hypothesis that psychopathology occurring at the time of an acute infection can lead to persistent symptoms that at least in the short term resemble those of the acute illness. This relationship breaks down after 6 months, when symptoms become less specific and may be conditioned by exhausting and distressing social situations other than acute illness.

Increased rectal mucosal expression of interleukin 1beta in recently acquired post-infectious irritable bowel syndrome.

BACKGROUND AND AIMS: Chronic bowel disturbances resembling irritable bowel syndrome (IBS) develop in approximately 25% of patients after an episode of infectious diarrhoea. Although we have previously shown that psychosocial factors operating at the time of, or prior to, the acute illness appear to predict the development of post-infectious IBS (PI-IBS), our finding of an increased inflammatory cell number in the rectum persisting for at least three months after the acute infection suggested that there is also an organic component involved in the development of PI-IBS. To evaluate this further, we measured expressions of interleukin 1beta (IL-1beta) and its receptor antagonist (IL-1ra) in these patients to provide additional evidence that the pathogenesis of PI-IBS is underpinned by an inflammatory process. METHODS: Sequential rectal biopsy samples were prospectively obtained during and three months after acute gastroenteritis, from eight patients who developed post-infectious IBS (INF-IBS) and seven patients who returned to normal bowel habits after acute gastroenteritis (infection controls, INF-CON). Eighteen healthy volunteers who had not suffered from gastroenteritis in the preceding two years served as normal controls (NOR-CON). IL-1beta and IL-1ra gene expressions were assayed by reverse transcriptase-polymerase chain reaction, and their levels of expression were quantitated by optical densitometry after electrophoresis on agarose gel. RESULTS: INF-IBS patients exhibited significantly greater expression of IL-1beta mRNA in rectal biopsies than INF-CON patients both during and three months after acute gastroenteritis. Moreover, IL-1beta mRNA expression had increased in biopsies taken from INF-IBS patients at three months after the acute infection but no consistent change was observed in INF-CON patients. IL-1beta mRNA expression of INF-IBS patients at three months post gastroenteritis was significantly greater than NOR-CON whereas that of INF-CON patients was not significantly different from NOR-CON. Despite these differential changes in IL-1beta mRNA expression, no significant changes were observed in IL-1ra mRNA expression among the three groups. CONCLUSIONS: These findings indicate that those patients who develop IBS post infection exhibit greater IL-1beta mRNA expression, both during and after the infection, compared with individuals who do not develop PI-IBS. We conclude that such patients may be susceptible to inflammatory stimuli, and that inflammation may play a role in the pathogenesis of PI-IBS.

Food and hypersensitivity in functional dyspepsia.

It has long been known that stress affects both the stomach and colon, as shown by the very high prevalence of gastrointestinal symptoms among patients with psychiatric illness. The source may be limbic or peripheral, involving encoded memories or physiological changes. It is important to realise that physical symptoms such as those of functional dyspepsia do not only mean that the patient has a stomach disorder which needs to be identified and treated with specific pharmacological remedies, they often represent, in metaphorical and symbolic form, a state of disharmony brought about a specific psychosocial situation. It is only when that situation is understood and acknowledged that the patient can begin to get better.

A re-examination of the relationship between abuse experience and functional bowel disorders.

BACKGROUND: Previous research suggests that sufferers of irritable bowel syndrome (IBS) report a greater prevalence of sexually and physically abusive experiences than patients with organic gastrointestinal disorders and non-patient populations. This has led to suppositions that previous abusive experiences might predispose to the development of functional gastrointestinal disorders. This study aimed to investigate the hypothesis that the prevalence of previous abuse experiences in patients with functional bowel disorders (FBD) is greater than it is in patients with a painful organic bowel disorder and healthy control subjects. METHODS: Fifty-three idiopathic constipation patients were compared with matched control groups of 50 IBS patients, 51 Crohn disease patients and 53 non-patient control subjects. Measures of previous abuse experiences were taken using a self-report questionnaire and a semistructured interview. Other questionnaires of psychological distress were also administered. RESULTS: No significant differences were found between all four groups, both for measures of abuse and for psychological distress. However, patients who reported past abuse, irrespective of their FBD status. demonstrated significantly higher levels of current psychological distress. CONCLUSIONS: These results challenge the current assumption that past abuse experiences may be significant in the later presentation of functional bowel disorders, but suggest that previous abuse experience might be related to a general level of psychopathology.

An investigation of the role of oro-sensory stimulation in sugar satiety?

OBJECTIVE: To investigate whether oral factors stimulated by the presence of sucrose in the mouth are involved in the suppression of appetite following sucrose ingestion. DESIGN: Ten male and 10 female healthy volunteers participated in four experimental conditions designed to provide differing levels of oro-sensory stimulation. Appetite and energy intake from a test meal were measured after subjects chewed and ingested sucrose-containing pastilles over a 10 min period, consumed a sucrose-containing jelly over a 5 min period, consumed a sucrose-containing drink within 2 min and drank plain water within 2 min. The three sucrose-containing preloads were similar in nutrient composition, each containing 251 kJ. RESULTS: Ratings of hunger and fullness did not differ between the four conditions following ingestion of the preloads. However, energy intake from a test lunch was significantly reduced after consuming the pastilles when compared with the plain water and equicaloric sweet drink conditions. CONCLUSION: These results suggest that enhanced oro-sensory stimulation from chewing the sweet food was involved in the suppression of food intake.

Comparison of oral and gastric administration of sucrose and maltose on gastric emptying rate and appetite.

OBJECTIVES: To investigate mechanisms by which specific sugars affect feeding behaviour. DESIGN: In an initial study, gastric emptying rate and appetite were measured following ingestion of lemon flavoured solutions of sucrose, maltose (2160 kJ, 575 ml) and water control (67 kJ, 575 ml) given in randomised order on separate days to six male volunteers. In a second study, the effects of intragastric infusions of sucrose and maltose on appetite and gastric emptying were compared in six male volunteers. RESULTS: When given orally, both the sucrose and maltose solutions slowed gastric emptying compared with water, however sucrose emptied at a faster rate than maltose. The sucrose preload increased fullness and decreased prospective consumption during the following 3 h compared with maltose and water. When administered intragastrically, the gastric emptying rate of sucrose was again faster than that of maltose but there was no difference in ratings of hunger, fullness or prospective consumption for 3 h following the infusions. CONCLUSIONS: These results show that gastric emptying of sucrose is faster than that of maltose and suggest that gastric emptying rate and hence period of gastric distension is not the predominant factor regulating appetite by these sugars. The differences observed between oral and gastric delivery suggest that oro-sensory and cognitive factors, possibly stimulated by the sweetness of sucrose, were involved in the induction of satiety.

Adaptation to high-fat diet accelerates emptying of fat but not carbohydrate test meals in humans.

Previous work has shown that the gastric emptying rate in animals and humans can adapt due to previous dietary intake. The present study investigated whether adaptation in gastric emptying rate due to consumption of a high-fat diet (HFD) is nutrient specific in humans. Gastric emptying of high-fat and high-carbohydrate test meals was measured (using gamma scintigraphy) before and after consumption of an HFD for 14 days in eight free-living male volunteers. Visual analog ratings of appetite were recorded throughout each test. There was no effect of HFD on any parameters of gastric emptying rate (lag phase, half-emptying time, and linear emptying rate) measured for carbohydrate test meals. HFD led to an acceleration of the linear emptying rate of the high-fat test meal (0.36 vs. 0.47%/min; P < 0.05). All meals reduced appetite ratings, but there were no differences between tests. These results support our previous findings of accelerated gastric emptying of high-fat test meals following an HFD and show that these changes appear to be nutrient specific, confirming recent studies in rats.

Effect of a lacto-ovo vegetarian diet on fasting small intestinal motility.

BACKGROUND: Changes in diet can alter gastric and small intestinal (SI) motility. The effects of a vegetarian diet on fasting SI motility are unknown. METHODS: Manometric studies were performed in 9 lacto-ovo vegetarians (7 women) and 9 omnivores (7 women) of similar age and body mass index. On each study day, manometry was used to assess SI motility for 5 h, or 3 complete cycles of the interdigestive motor complex (IDMC). Lacto-ovo vegetarians were studied once: omnivores were studied twice, on their usual diet, and after consuming a 14-day lacto-ovo vegetarian diet. Diet diaries were kept for 5 days prior to each manometric study. Data were analysed for dietary composition and for cycle length and duration of each phase (I, II and III) of the IDMC. RESULTS: Dietary intake did not differ between chronic vegetarians and chronic omnivores apart from a trend to higher fibre intake (29 +/- 3 versus 20 +/- 3 g/day; P = 0.058). Omnivores eating a vegetarian diet showed a trend to decreased alcohol consumption (P = 0.068), but did not increase their fibre intake (20 +/- 3 versus 21 +/- 3 g/day). Neither cycle length nor duration of each IDMC phase differed between chronic vegetarians and chronic omnivores. After 14 days of a vegetarian diet, omnivores had a reduction in cycle length (128 +/- 19 versus 86 +/- 12 min; P = 0.02), with a non-significant reduction of Phase II (99 +/- 20 versus 50 +/- 8 min: P = 0.066). CONCLUSIONS: A chronic vegetarian diet has no major effect on fasting SI motility; but acute dietary change may alter the cycle length and component phases of the IDMC.

Exercise-induced nausea is exaggerated by eating.

This study was conducted to determine whether and under what circumstances exercise causes nausea. Twelve healthy volunteers (20-37 years), including six athletes, participated in the study. Subjects were studied on seven occasions. Each subject performed low and high-intensity exercise without eating, immediately after eating a beef patty and 60 min after eating. Besides these exercise experiments, effect of meal on nausea was studied in each subject for 180 min without exercise. Exercise was done on a bicycle ergometer for 60 min at 40-50% maximal heart rate reserve and 20 min at 70-80% maximal heart rate reserve. Subjects were tested for nausea by visual analogue scales. Both low and high-intensity exercise caused nausea. Scores for nausea were greater during exercise at fasting state and immediately after eating than those without exercise (p<0.05 during low-intensity exercise, and p<0.01 during high-intensity exercise). Immediately after eating, scores for nausea were greater during high-intensity exercise than during low-intensity exercise (p<0.05). During high-intensity exercise, scores for nausea were greater immediately after eating than without eating (p<0.05). There were no differences in ratings for nausea between the sexes in any of the experimental conditions. Training did not decrease exercise-induced nausea. In conclusion, exercise causes nausea, the severity of which is related to exercise intensity and food intake, but not sex differences nor physical training.

The effects of intestinal infusion of long-chain fatty acids on food intake in humans.

BACKGROUND & AIMS: Dietary fat intake is related to the degree of obesity, but the specific mechanisms by which fats regulate food intake in humans are unclear. We compared food intake suppression, plasma triglyceride appearance, and cholecystokinin (CCK) response after intestinal infusion of oils enriched with C18 fatty acids of increasing unsaturation. METHODS: Food intake and appetite changes after upper intestinal infusion of 0.9% saline, 20% Intralipid, and 20% emulsions of oils enriched with stearic, oleic, and linoleic acids were tested in 10 healthy male volunteers. Plasma triglyceride appearance and CCK release were tested separately in 7 additional volunteers. RESULTS: Intralipid and linoleic acid infusions significantly reduced food intake compared with saline infusion (P<0.05). No changes were observed in appetite ratings. There were no differences in plasma triglyceride response over the initial 75 minutes of intestinal infusion. Plasma CCK concentration increased after all lipid infusions (P<0.001), Intralipid infusion produced the highest increase in plasma CCK (P<0.05), and CCK response was similar between the 3 enriched oil emulsions. CONCLUSIONS: These results indicate marked differences in the ability of C18 fatty acids to reduce food intake that appear not to be related to rate of absorption but may partially be explained by CCK release.

Harnessing the patient's powers of recovery: the role of the psychotherapies in the irritable bowel syndrome.

The aim of this chapter is to provide a clear and balanced account of the role of the various forms of psychotherapy in the irritable bowel syndrome (IBS). It commences with an account of the philosophical basis for psychotherapy, attempting to integrate the concepts of autonomic arousal, repression, conversion and a developmental disorder of thinking and emotional expression. These concepts are used to explain why separation and loss can lead to the development of IBS and how the gut is such an important vehicle for emotional expression. Against this background the role and philosophy of relaxation therapy, hypnotherapy, biofeedback, cognitive behavioural therapy and analytical psychotherapy are discussed. These therapies describe a philosophical approach that is quite different from biomedical treatments in that it attempts to harness the patient's own powers for recovery. For that reason the efficacy of psychotherapies cannot be evaluated by randomized controlled trials. Psychotherapies rely on the relationship between therapist and patient and vary according to whether the locus of responsibility lies mainly with the therapist or mainly with the patient. Different patients may well require different therapies.

Comparison of the effects of a high-fat and high-carbohydrate soup delivered orally and intragastrically on gastric emptying, appetite, and eating behaviour.

To investigate the effects of fat and carbohydrate on appetite, food intake and gastric emptying with and without the influence of orosensory factors, a group of nine healthy, fasted male subjects took part in two separate paired experiments involving high-fat and high-carbohydrate radiolabelled soup preloads. In the first experiment subjects received direct intragastric isocaloric infusions of either a high-fat tomato soup or a high-carbohydrate tomato soup (400 kcal in 425 mL) over 15 min, on two occasions. In the second paired experiment subjects ingested the same high-fat and high-carbohydrate soup over 15 min. In both experiments ratings of hunger and fullness were recorded over a period of 135 min and gastric emptying was measured by scintigraphy. Food intake was evaluated from a test meal (yoghurt drink) given 2 h after the end of the soup infusion/ingestion. When soup was administered intragastrically (Experiment 1) both the high-fat and high-carbohydrate soup preloads suppressed appetite ratings from baseline, but there were no differences in ratings of hunger and fullness, food intake from the test meal, or rate of gastric emptying between the two soup preloads. When the same soups were ingested (Experiment 2), the high-fat soup suppressed hunger, induced fullness, and slowed gastric emptying more than the high-carbohydrate soup and also tended to be more effective at reducing energy intake from the test meal. The results of these studies demonstrate that orosensory stimulation plays an important role in appetite regulation, and also indicate that subtle differences in orosensory stimulation produced by particular nutrients may profoundly influence appetite and gastrointestinal responses.

Validation of a specific quality of life questionnaire for functional digestive disorders.

BACKGROUND: Dyspepsia and irritable bowel syndrome are suitable conditions for assessment of quality of life. Their similarities justify the elaboration of a single specific questionnaire for the two conditions. AIMS: To examine the process leading to the validation of the psychometric properties of the functional digestive disorders quality of life questionnaire (FDDQL). METHODS: Initially, the questionnaire was given to 154 patients, to assess its acceptability and reproducibility, analyse its content, and reduce the number of items. Its responsiveness was tested during two therapeutic trials which included 428 patients. The questionnaire has been translated into French, English, and German. The psychometric validation study was conducted in France, United Kingdom, and Germany by 187 practitioners. A total of 401 patients with dyspepsia or irritable bowel syndrome, defined by the Rome criteria, filled in the FDDQL and generic SF-36 questionnaires. RESULTS: The structure of the FDDQL scales was checked by factorial analysis. Its reliability was expressed by a Cronbach's alpha coefficient of 0.94. Assessment of its discriminant validity showed that the more severe the functional digestive disorders, the more impaired the quality of life (p<0.05). Concurrent validity was supported by the correlation found between the FDDQL and SF-36 questionnaire scales. The final version of the questionnaire contains 43 items belonging to eight domains. CONCLUSIONS: The properties of the FDDQL questionnaire, available in French, English, and German, make it appropriate for use in clinical trials designed to evaluate its responsiveness to treatment among patients with dyspepsia and irritable bowel syndrome.

An examination of the effects of isoenergetic intragastric infusions of pure macronutrients on cold pain perception in healthy human volunteers.

Our previous study demonstrated that meals, particularly when rich in fat, significantly reduced the pain induced by the cold pressor stimulus in healthy human subjects. To determine the mechanisms involved, the aim of this study was to bypass the taste and cognitive component of food and to investigate the scope of these analgesic effects with direct intragastric infusion of pure macronutrients in a group of 16 healthy human volunteers (eight male and eight female) on the response to cold-induced pain. All subjects underwent the cold pressor test (CPT) on three occasions in a counterbalanced order: before and after intragastric intubation and infusion of isoenergetic fat (10% intralipid), carbohydrate (CHO-maltodextrin), and a control infusion of isotonic saline. All solutions were of equal volume and administered at room temperature. The CPT was carried out four times on each test day, once before intubation, and 0.5, 1.5, and 2.5 h after intragastric infusion. Radial pulse and blood pressure measurements and visual analogue scales of mood/emotional state were carried out before and after each CPT. There were no significant differences in pain scores between the three test conditions, suggesting that by bypassing the cognitive and taste component of eating, the trigger for any postingestive analgesic effects of food are lost.