Lactase deficiency and lactose intolerance-related symptoms in adult healthy subjects from western France]

The prevalence of lactase deficiency (LD) and lactose intolerance is not well known in France. Using breath hydrogen and methane analysis after 50 g oral lactose load, we investigated the prevalences of LD, lactose intolerance, and methane producer status in 102 healthy adults born in western France, and we examined the relationships between these parameters and the daily milk consumption. In 10 subjects with LD and lactose intolerance, we studied the reproducibility of the lactose hydrogen breath test results for the diagnosis of LD and lactose intolerance and estimated the quantity of lactose malabsorbed in comparison with the lactulose hydrogen breath test. The prevalence of LD was 23.4 percent and symptoms of lactose intolerance were observed in 50 percent of the 24 subjects with LD. The daily milk consumption was not significantly different in the 24 subjects with LD and in the 78 subjects without LD (281 +/- 197 vs 303 +/- 217 ml/24 h). The prevalence of methane producer status was 42.1 percent. The symptomatic group of lactose malabsorbers (n = 12) was characterized by a shorter lactose mouth to caecum transit time (39 +/- 20 vs 88 +/- 48 min; P less than 0.05), and more marked hydrogen production (6.1 +/- 2.3 vs 3.4 +/- 2.4 10(3) ppm.min; P less than 0.04). In the 10 subjects with LD and lactose intolerance, the hydrogen breath test was reproducible for diagnosis of LD and lactose intolerance, and for hydrogen production. The quantity of lactose malabsorbed was 60 percent. In France, symptoms of lactose intolerance are not severe and do not affect the daily consumption of milk and dairy products.     

Irritable bowel syndrome: relationship of disorders in the transit of a single solid meal to symptom patterns.

The time taken for a solid meal to pass through the stomach, small intestine, and colon was measured in 61 patients with irritable bowel syndrome, subdivided according to their presenting symptoms, and in 53 healthy volunteers. Small bowel transit times were significantly shorter in patients who complained predominantly of diarrhoea (3.3 +/- 0.3 vs 4.2 +/- 0.2 h; p = 0.01; n = 21) and significantly longer in patients who complained predominantly of constipation (5.4 +/- 0.3 vs 4.2 +/- 0.2 h; p less than 0.01; n = 23) or pain and distension (5.4 +/- 0.4 vs 4.2 +/- 0.2 h; p less than 0.01; n = 17) compared with controls. Whole gut transit times were shorter in patients who complained of diarrhoea (35 +/- 5 vs 53 +/- 4 h; p less than 0.01), and longer in patients with constipation (87 +/- 13 vs 53 +/- 4 h; p less than 0.05) compared with controls. No significant differences in gastric emptying rates were shown between any of the patient groups and normal controls. Thirty-four patients reported pain, particularly in the right iliac fossa, during the meal transit test, and in 25 of these (74%), the onset of the pain was associated with the arrival of residues of the test meal in the caecum. Our results indicate that irritable bowel syndrome should be considered a disease of the small intestine as well as the colon.     

Assessment of lactose absorption by measurement of urinary galactose

Individuals with sufficient intestinal lactase hydrolyze ingested lactose to galactose and glucose and these monosaccharides are absorbed. Lactose is not digested completely when intestinal lactase activity is low and the disaccharide is malabsorbed. Breath hydrogen excretion after lactose ingestion is used commonly to diagnose lactose malabsorption. However, no direct tests are currently used to assess lactose absorption. We tested a new method of assessing lactose absorption in 26 healthy individuals. Each subject ingested 50 g of lactose. Participants were evaluated for lactose malabsorption using a standard 3-h breath hydrogen test. In addition, the urinary excretions of galactose, lactose, and creatinine were quantitated for 3-5 h after lactose ingestion. On the basis of breath hydrogen analysis after lactose ingestion, 12 individuals were lactose malabsorbers (defined as a rise in the breath hydrogen concentration of greater than 20 parts per million above the baseline value). The 14 subjects who did not malabsorb lactose by breath hydrogen testing (defined as a rise in the breath hydrogen concentration of less than or equal to 20 parts per million above the baseline value), had significantly more galactose in their urine 1, 2, and 3 h after lactose ingestion than lactose malabsorbers. The ratio of excreted lactose to excreted galactose was significantly decreased in lactose absorbers compared with lactose malabsorbers (p less than 0.001). Determination of the ratio of urinary galactose to urinary creatinine separated lactose absorbers from lactose malabsorbers completely (p less than 0.001). We conclude from this study that the determination of urinary galactose, urinary lactose/galactose ratio, and urinary galactose/creatinine ratio may be used to assess lactose digestion and absorption in healthy adults.     

Acute Effects of Abdominopelvic Irradiation on the Orocecal Transit Time: Its Relation to Clinical Symptoms, and Bile Salt and Lactose Malabsorption

Twenty-five patients with abdominopelvic malignant tumors receiving irradiation were studied. The following items were assessed before, during, and at the end of the radiation period: 1) clinical symptoms, scored on the basis of their severity; 2) orocecal transit time (lactulose-H2 breath test); and 3) absorption of lactose and bile salts. Ninety-two percent of the patients showed clinical symptoms suggestive of acute radiation enteropathy, mainly diarrhea. A significant acceleration of the orocecal transit was observed during the study: 70 +/- 6.9 min vs 63.3 +/- 6.3 min vs 44.3 +/- 5.1 min (F = 5.49, p = 0.008), being faster in patients with severe diarrhea (F = 3.25, p = 0.05). Forty-four percent and 57% of the patients developed lactose and bile salt malabsorption, respectively. A decrease in the transit time was observed, independent of the absorption or malabsorption of such substances. However, the orocecal transit was faster in those lactose malabsorbers with severe diarrhea, than in those with mild diarrhea (F = 4.2, p = 0.03). The results suggest that acceleration of orocecal transit may be a major factor in the pathophysiology of radiation-induced diarrhea, whereas lactose malabsorption may contribute to the severity of the diarrhea.     

Simultaneous measurement of gastric emptying, small bowel residence and colonic filling of a solid meal by the use of the gamma camera

A method for determining the profiles of gastric emptying, small intestinal residence, and colonic filling of a solid test meal, labelled with 250 microCi 99mTechnetium sulphur colloid has been evaluated in nine healthy volunteers and six patients with a disturbance in bowel habit. Mean small bowel transit time was determined by deconvolving the rate of colonic filling with the rate of gastric emptying. In normal subjects, the stomach appeared to empty exponentially with a half time of 1.2 +/- 0.3 hours (mean +/- SD). Food reached the colon by 2.8 +/- 1.5 hours. The mean small bowel transit time was 4.0 +/- 1.4 hours. In most normal subjects, the colon appeared to fill in a linear fashion with approximately 16% food residues entering every hour, and the profile of colonic filling in normal subjects was similar to the profile of ileal emptying observed after feeding a similar radiolabelled solid meal to 14 patients equipped with terminal ileostomies. There was a highly significant correlation between the onset of breath hydrogen excretion and the appearance of radioactivity over the caecum (r = 0.88, p less than 0.01), though in one third of subjects the increase in caecal radioactivity preceded the rise in breath hydrogen concentration by more than 20 minutes. There was also a highly significant correlation between the mean transit time and values for colonic filling but not values for gastric emptying. Patients with irritable bowel syndrome who had diarrhoea tended towards short small bowel transit and early colonic filling, whereas patients who have constipation tended towards long small bowel transit and delayed colonic filling. This method offers a novel means of assessing small bowel transit time, small bowel residence and the profile of colonic filling in man.     

Electrochemical detector for breath hydrogen determination: measurement of small bowel transit time in normal subjects and patients with the irritable bowel syndrome.

A method is described for the measurement of hydrogen in expired air, using an electrochemical detector. The apparatus is simple to use and sensitive. Its application is illustrated by studies of small bowel transit time made by measuring the time between oral ingestion of the unabsorbable carbohydrate lactulose and a rise in the concentration of hydrogen in expired air. In 20 control subjects transit time was 93.0 +/- 6.6 minutes, while in 16 patients with diarrhoea due to the irritable bowel syndrome it was 54.1 +/- 6.3 minutes (P less than 0.001), suggesting an abnormality in small intestinal motility in these patients. Loperamide, a potent antidiarrhoeal agent, increased transit time in 12 of these patients from 56.3 +/- 6.7 to 100.0 +/- 10.2 minutes (P less than 0.001).     

Intestinal transit in anxiety and depression.

BACKGROUND: Patients with anxiety and depression often have bowel symptoms. Until now, studies investigating a link between altered bowel habit and psychological illness have focused on patients with disturbed defecation presenting to gastroenterologists. AIMS: To determine whether patients with anxiety and depression have objective evidence of abnormal intestinal transit irrespective of any bowel symptoms. METHODS: 21 psychiatric outpatients fulfilling research criteria for generalised anxiety disorder and/or major depression, and 21 healthy volunteers were studied. Orocaecal transit time (OCTT) was measured by lactulose hydrogen breath test. Whole gut transit time (WGTT) was measured by abdominal radiography after ingestion of radio-opaque markers. RESULTS: Median (range) WGTT was shorter in patients with anxiety (14 (6-29) hours) than in patients with depression (49 (35-71) hours) (p < 0.001), and controls (42 (10-68) hours) (p < 0.001). In patients with anxiety, orocaecal transit time was shorter (60 (10-70) minutes) than in patients with depression (110 (60-180) minutes) (p < 0.01), and shorter than in controls (75 (50-140)) minutes (p < 0.05). The prolongation of transit times in depression compared with controls was not significant. However, WGTT correlated with both the Beck Depression Inventory score (r = 0.59, p < 0.01) and the depression score of the Hospital Anxiety and Depression scale (r = 0.66, p < 0.001). CONCLUSIONS: These objective measurements of intestinal transit in affective disorders are consistent with clinical impressions that anxiety is associated with increased bowel frequency, and depressed patients tend to be constipated; mood has an effect on intestinal motor function.     

Hydrogen Breath Test Assessment of Orocecal Transit Time; Comparison with Barium Meal Study

Orocecal transit time was measured simultaneously by the hydrogen breath test and a barium meal study in 12 hospitalized patients, the objective being to determine whether the former test accurately represents the orocecal transit time, and to establish an adequate criterion for the transit time, based on the former test. Two definitions of orocecal transit time by the hydrogen breath test were evaluated: the time from lactulose ingestion to a sustained increase of over 5 ppm above fasting levels in the end-expiratory hydrogen concentration (definition A) and the interval to that of over 10 ppm (definition B). The orocecal transit time measured by the radiologic method was 63 +/- 9 min (mean +/- SEM), whereas that using definition A of the hydrogen breath test was 74 +/- 9 min, and that using definition B was 87 +/- 10 min. Transit times determined by both definitions closely correlated with that obtained by the radiologic method (A, r = 0.86, p less than 0.01; B, r = 0.81, p less than 0.01). Therefore, elevation of end-expiratory hydrogen concentrations seemed to coincide with cecal appearance of the head of the lactulose load. When the mean transit times were compared with findings in case of the radiologic method, definition A rather than B appeared to be more appropriate to determine orocecal transit time.     

Lactose malabsorption, irritable bowel syndrome and self-reported milk intolerance

BACKGROUND: The relationship between lactose malabsorption, irritable bowel syndrome and development of intestinal symptoms is unclear, especially when the ingested dose of milk is small. Thus, the role of hydrogen breath testing in the diagnostic work-up of patients with nonspecific intestinal symptoms is still debated. AIMS: To establish the relationship between lactose malabsorption, severe self-reported milk intolerance, irritable bowel syndrome and related symptoms. METHODS: The prevalence of lactose malabsorption was prospectively assessed by means of a hydrogen breath test in 839 patients (503 with irritable bowel syndrome, based on the Rome criteria, regularly consuming milk, and 336 subjects who identified themself as milk intolerant, after an oral load of 25 g lactose). The test was considered "positive" when a hydrogen peak exceeding 20 ppm over baseline values was observed in two or more samples. Attempts were also made to establish whether the predominant presenting symptom (diarrhoea, constipation, alternating diarrhoea and constipation, pain and gaseousness) might be helpful in predicting the outcome of the breath test. RESULTS: The prevalence of a positive breath test was comparable in the two groups (337 patients with irritable bowel syndrome (66.9%) vs 240 patients with milk intolerance (71.4%)). The same holds true for the first peak of hydrogen excretion, total hydrogen output and prevalence of symptoms during, and in the four hours after, the test. The predominant presenting symptom was not useful for predicting outcome of the test either in regular milk users or in milk intolerant subjects. CONCLUSIONS: The almost identical results of the lactose breath test of patients with irritable bowel syndrome and subjects with self-reported milk intolerance suggests that the two conditions overlap to such an extent that the clinical approach should be the same. A lactose breath test should always be included in the diagnostic work-up for irritable bowel syndrome, as fermentation of malabsorbed lactose is likely responsible for triggering symptoms. Conversely, lactase deficiency is probably irrelevant in most subjects not affected by irritable bowel syndrome, within a moderate milk consumption.     

Stress effects on gastrointestinal transit in the rat.

Previous investigations of stress effects on gastric emptying, orocaecal, and colonic transit in rats have produced conflicting results. Here one type of stressor, a 'passive avoidance' situation, was used to investigate its effects on gastric emptying, orocaecal and colonic transit. After the rats had been trained to eat a standard amount of semisolid food, gastric emptying was determined (n = 12) by the food remaining in the stomach after various periods of rest, or stress exposure. Orocaecal transit (n = 14) was determined by breath hydrogen measurements after the food had been labelled with 1 g lactose. Colonic transit (n = 18) was measured as the arrival time of coloured faeces after infusion of a carmine red solution into the caecum through a chronically implanted catheter. The stressor had differential effects on transit through the stomach, small bowel and colon: gastric emptying was delayed (p less than 0.05) after stress (t1/2 = 2.66 h after stress, 1.97 h at rest). Orocaecal transit was accelerated (p less than 0.05) after stress; transit time decreased from 124.3 min at rest to 86.2 min after stress. Colonic transit was accelerated (p less than 0.01) under stress, from 15.5 h to 1.29 h. It is concluded that gastrointestinal transit in different parts of the gastrointestinal tract is differently affected by central nervous stimuli.     

Evidence for hypomotility in non-ulcer dyspepsia: a prospective multifactorial study.

A prospective multifactorial study of symptoms and disturbance of gastrointestinal function has been undertaken in 50 patients with non-ulcer dyspepsia. Objective tests including solid meal gastric emptying studies, gastric acid secretion, E-HIDA scintiscan for enterogastric bile reflux, and hydrogen breath studies were carried out in all patients and validated against control data. Gastroscopy and biopsy were carried out in non-ulcer dyspepsia patients only. Non-ulcer dyspepsia patients were categorised on the basis of predominant symptoms as: dysmotility-like dyspepsia (n = 22); essential dyspepsia (n = 14), gastro-oesophageal reflux-like dyspepsia (n = 11); and ulcer-like dyspepsia (n = 3). In the total non-ulcer dyspepsia population, solid meal gastric emptying was delayed (T50 mean (SEM) = 102 (6) minutes (patients) v 64 (6) minutes (controls), (p less than 0.01) and high incidences of gastritis (n = 26) and Helicobacter pyloridis infection (n = 18) were found. An inverse correlation was observed between solid meal gastric emptying and fasting peak acid output (r = -0.4; p less than 0.01). Indeed gastric emptying was particularly prolonged in eight patients (T50 mean (SEM) = 139 (15) minutes) with hypochlorhydria. In the non-ulcer dyspepsia population oral to caecal transit time of a solid meal was delayed (mean SEM = 302 (14) minutes (patients) v 244 (12) minutes (controls) (p less than 0.01]. Seven patients had a dual peak of breath hydrogen suggestive of small bowel bacterial overgrowth. No association was observed between symptoms and any of the objective abnormalities. This multifactorial study has shown that hypomotility, including gastroparesis and delayed small bowel transit, is common in non-ulcer dyspepsia and may be related to other disorders of gastrointestinal function. No relation between symptoms and disorders of function, however, has been shown.     

Effect of chronic alcohol drinking and liver cirrhosis on oro-cecal transit time (H2 breath test)

In a clinical study (1.1.1986-28.2.1988) the oro-cecal transit time of lactulose was studied in 45 patients with liver cirrhosis of different etiologies by hydrogen breath test. The results were compared to the transit time of 16 healthy volunteers. The oro-cecal transit time of patients with alcoholic cirrhosis (means = 154 +/- 29 min.) was significantly increased (P less than or equal to 0.001) while non alcoholic cirrhosis (means = 99 +/- 34 min.) did not differ from the control group (means = 98 +/- 16 min.) As an explanation of the increased oro-cecal transit time an alcoholic autonomic neuropathy (- greater than n. vagus) is discussed.     

Orocaecal transit time in health and in thyroid disease.

Altered bowel habit commonly occurs in thyroid disease. We measured orocaecal transit in healthy volunteers and in hyperthyroid and hypothyroid patients before and after treatment, using the lactulose hydrogen breath test incorporating a standard liquid meal to obtain a more physiological assessment. Mean transit time in 12 control subjects was 85 (8) minutes (mean (SE)) (mean coefficient of variation between replicate studies, 8.6% (3%)). In eighteen hyperthyroid patients transit was more rapid at 49 (4) minutes (p less than 0.01). Ten hypothyroid patients had a transit time similar to controls at 91 (9) minutes. Transit time returned to normal in thyrotoxic patients after treatment but in eight hypothyroid patients retested, it remained unchanged. Our findings suggest that (a) the inclusion of a liquid meal provides a reproducible method of measuring orocaecal transit using the lactulose hydrogen breath test, (b) rapid small bowel transit in thyrotoxicosis may be one factor in the diarrhoea which is a feature of the disease and (c) if altered gut transit is the cause of sluggish bowel habit in hypothyroidism, delay in the colon, and not small bowel, is likely to be responsible.     

Fructose and Sorbitol Malabsorption in Ambulatory Patients with Functional Dyspepsia Comparison with Lactose Maldigestion/Malabsorption

The aim of this study was to study sugarmaldigestion/malabsorption in patients with functionaldyspepsia using H breath testing. End-expiratory breathH after separate 2 challenges with lactose (25 g), fructose (25 g), and sorbitol (5 g) were usedto determine malabsorption, as well as small boweltransit time (SBTT). Five hundred twenty patients withfunctional dyspepsia received all three challenges. Smaller groups were also tested after lactulose(10 g, N = 36) and glucose (50 g, N = 90) challenges.Fructose and sorbitol were closely linked with respectto absorption and malabsorption status. Only in the case of lactose maldigestion/malabsorption wasthere a greater than random prevalence of malabsorption(P < 0.001) for fructose and sorbitol. In contrast tolactose, ethnic origin did not influence fructose or sorbitol malabsorption, and femalespredominated among fructose and sorbitol malabsorbers.In Jews, the prevalence of lactosemaldigestion/malabsorption decreased in the age group of25-55 and subsequently rose after 55, while fructose and sorbitolmalabsorption decreased progressively with advancingage. With respect to small bowel transit time (SBTT), inthe case of sorbitol and lactulose, it was significantly greater (P < 0.05) than those for fructoseand lactose. Multiple sugar malabsorptions are commonwhen lactose maldigestion/malabsorption ispresent.     

Adaptation of hydrogen analysis to measure stomach to caecum transit time in the rat

Excreted hydrogen analysis was used to measure stomach to caecum transit time of the head of a test meal in 120 rats fed by gavage. Results were compared with the distribution of a labelled test meal in the gastrointestinal tract of rats killed at different time intervals after gavage. Values for stomach to caecum transit were compatible with the distribution of labelled meals in 91% of animals, although in the remainder the hydrogen concentration had not risen even though food residues were in the caecum when the animals were killed. The technique gave reproducible results; the coefficients of variation for four studies carried out in each of six animals varied between 4 and 14%. A meal consisting of homogenised baked beans had a significantly shorter stomach to caecum transit time (88.1 +/- 4.5 min; mean +/- SE; n = 21; p less than 0.001) than an equivalent volume of Complan/lactulose (180.9 +/- 8.7 min; n = 13). This technique was used to investigate the effect of ileal infusion of a fat emulsion (20% Intralipid) via a chronically implanted intestinal cannula on the stomach to caecum transit time of a bean meal, in a series of paired studies carried out in six rats. Stomach to caecum transit time was significantly delayed during ileal infusion of 20% Intralipid compared with the control infusion of an isotonic saline solution (218.3 +/- 21 min v 106.7 +/- 33 min Intralipid v saline; n = 6; p less than 0.001).     

Is lactose intolerance implicated in the development of post-infectious irritable bowel syndrome or functional diarrhoea in previously asymptomatic people?

OBJECTIVE: The relationship between lactose intolerance and post-infectious irritable bowel syndrome (IBS) in adults is uncertain. Bowel symptoms may persist after bacterial gastroenteritis and as post-infectious IBS. Acquired lactose intolerance may follow viral enteric infections in children. We compared the frequency of lactose intolerance after bacterial gastroenteritis in adults with and without symptoms of IBS or functional diarrhoea at 3-6-months' follow-up. DESIGN: A prospective cohort study was conducted. METHODS: All subjects with bacterial gastroenteritis confirmed by stool culture from the microbiology laboratory and without prior IBS or functional diarrhoea were eligible to participate. IBS and functional diarrhoea were diagnosed via self-completed Rome II modular questionnaires. Lactose intolerance was determined from a rise in breath hydrogen and plasma glucose and symptoms. RESULTS: One hundred and twenty-eight subjects with bacterial gastroenteritis were followed prospectively, from which a smaller cohort of 42 subjects took part in this study. The cohort was comprised of 24/25 subjects who developed post-infectious IBS (n = 16) or functional diarrhoea (n = 8) (9 male, 15 female) and 18 random controls (8 male, 10 female) chosen from the group without IBS or functional diarrhoea. The mean age of the subjects was 44.4 years (range 25-76 years). In the group with functional diarrhoea or IBS, four subjects had failure of the plasma glucose to rise but none had abnormal glucose hydrogen breath tests. In the control subjects, one had a positive combined test and six had failure of plasma glucose to rise alone. No subject developed symptoms during the test. CONCLUSIONS: Bacterial gastroenteritis did not cause persistent lactose intolerance in our study population. Lactose intolerance does not appear to be implicated in the aetiology of post-infectious bowel symptoms, including IBS. Advice to avoid dairy products in patients presenting with post-infectious IBS on the basis that they may have lactose intolerance appears unnecessary in patients from northern England.     

Development, Validation, and Applicability of a Symptoms Questionnaire for Lactose Malabsorption Screening

Lactase deficiency has a high prevalence worldwide. Thus, a valid symptom scale would be a useful tool for identifying patients with lactose malabsorption. Objective To develop, validate, and apply a symptoms questionnaire on lactose malabsorption to identify lactose malabsorbers diagnosed with the gold-standard hydrogen breath test. Methods In the first part of the study, 292 patients completed a questionnaire at the end of a 50-g lactose breath test. The questionnaire included five items (diarrhea, abdominal cramping, vomiting, audible bowel sounds, and flatulence or gas) scored on a 10-cm visual analogue scale. In the second part of the study, 171 patients completed the questionnaire twice: first, according to their opinion when consuming dairy products at home and second, after a 50-g lactose breath test. Patients were grouped as absorbers or malabsorbers according to the result of the breath test. Results Diarrhea, abdominal cramping, and flatulence were scored significantly higher in malabsorbers than in absorbers. Total score of the symptomatic questionnaire was significantly higher in malabsorbers (17.5 versus 3.0, P < 0.01). According to receiver operator characteristics (ROC) analysis, the most discriminant cut-off of the total score to identify lactose malabsorption was 6.5 (sensitivity 0.75, specificity 0.67). In 58 malabsorbers the effect size of the questionnaire to determine sensitivity to change was 1.32. In the second part of the study, scoring of the home questionnaire was higher than after the lactose-breath test. The lactose malabsorbers rate was higher according to the home questionnaire than after the lactose breath test (72% versus 52%). The home questionnaire had excellent sensitivity (0.82) but low specificity (0.35). Conclusion We developed and validated a five-item symptoms questionnaire for lactose malabsorption. This is a valid test that permits patients with a total score lower than 7 to be excluded from future studies.     

Effects of a pharmacological dose of cholecystokinin on bile acid kinetics and biliary cholesterol saturation in man.

In order to study the mechanisms influencing bile acid pool size and cholesterol saturation index of fasting gall bladder bile, eight obese volunteers were placed on a low calorie diet for six weeks, and given intramuscular injections of a pharmacological dose of cholecystokinin octapeptide (CCK-OP, 5 micrograms) at mealtimes for half that period (alternating order). During CCK-OP administration, postprandial emptying of the gall bladder (mean +/- SEM) increased from 58 +/- 11% to 82 +/- 5% (p less than 0.005), and small intestinal transit time decreased from 205 +/- 27 to 178 +/- 26 minutes (NS). Bile acid pool size decreased from 4.6 +/- 0.3 to 3.1 +/- 0.3 mmol (p less than 0.001), while fractional turnover rate for chenodeoxycholic acid increased from 0.23 +/- 0.02 to 0.36 +/- 0.03 per day (p less than 0.005), suggesting an increase in recycling frequency of the pool. Synthesis rate was unchanged (0.43 +/- 0.08 vs 0.44 +/- 0.07 mmol/day), suggesting a new steady state. The cholesterol saturation index of fasting gall bladder bile increased in all subjects from 1.3 +/- 0.1 to 1.6 +/- 0.1 (p less than 0.005). Fasting gall bladder volume was reduced from 29 +/- 4 to 20 +/- 7 ml (p less than 0.01). Fractional turnover rate on the two regimens correlated with gall bladder emptying (n = 16, r = 0.61, p less than 0.01), but not with small intestinal transit time (r = 0.07, NS). Bile acid pool size correlated with fractional turnover rate (r = -0.73, p less than 0.005) and with cholesterol saturation index (r = -0.56, p less than 0.025). These findings suggest that CCK influences bile acid kinetics and cholesterol saturation index of fasting gall bladder in man; and that these effects of CCK are mainly mediated via alterations in gall bladder emptying rather than through alterations in small intestinal transit rate.     

Measurement of gastric emptying, intestinal transit time and colonic filling by scintiscan in healthy subjects

A scintigraphic technique allowing combined measurements of gastric emptying, small intestinal transit time and colonic filling was developed and its reproducibility assessed in 8 healthy volunteers. Each subject underwent four tests: a) two were performed in the fasting state (99mTc labelled water, added to lactulose), b) two in the postprandial state (balanced meal, 1,750 kJ, included pellets labelled with 111In, the gut transit of which being nearly the same as dietary fibers). Intestinal transit was modeled using linear operators (expressed as a convolution product). In fasting state (lactulose), orocecal transit time of water was 109 +/- 60 min and 89 +/- 36 min (m +/- DS) for the first and second tests, respectively. In the postprandial state, values were 297 +/- 37 min and 293 +/- 43 min respectively for the pellets. Small bowel transit times were 135 +/- 70 and 103 +/- 40 min respectively in fasting state for water, and 209 +/- 47 and 209 +/- 29 min respectively in postprandial state for the pellets. Determination of residual variance showed that reproducibility of the test was better in the postprandial state than in the fasting state. Water orocecal transit times measured using this technique and lactulose orocecal transit time measured using hydrogen breath test were strongly correlated (r = 0.98, n = 12, P less than 0.01). This isotopic method provides a reproducible assessment of gastric emptying, small bowel transit, and colonic filling and could represent a reliable and non invasive tool for further physiological and pharmacological studies.     

Milk is a useful test meal for measurement of small bowel transit time

To improve and standardize the measurement of small bowel transit time, milk was employed for the test meal instead of the conventional lactulose meal. Although 92% of the subjects were lactase deficient, only 2% were milk intolerant and 13% were lactose intolerant. Small bowel transit time with milk (milk breath hydrogen test) was 113±9 min (mean ± SE,n=20); the normal range calculated from the mean ±2 SD was 31–195 min. The coefficient of variation in the milk hydrogen breath test was 13 ± 4% (n=6), whereas in the lactulose hydrogen breath test, it was 39±16% (n=10). The frequency of non-hydrogen producers, the occurrence of discomfort, and the reproducibility were better, though not significantly so, in the milk hydrogen breath test than in the lactulose. Since lactase activity in the intestine is variable in lactase-deficient subjects, small bowel transit times for milk may change from subject to subject. However, individual reproducibility of the milk hydrogen breath test is good. It could be useful for pharmacological experiments using paired comparison, for screening tests, or for the follow up of diseases in which small bowel transit time is affected.