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Objective: To assess the effects of drug-induced changes in mean transit time (MTT) on the activity of human fecal flora in vitro. Methods: The activity of fecal flora was estimated by the ability of a fecal inoculum to ferment a substrate (beet fiber) in vitro in a batch system for 24h. The inoculum was collected from 8 healthy volunteers studied during three 3-week randomized periods, who received a controlled diet alone (control period) or the same diet with either cisapride or loperamide. Cisapride and loperamide were adjusted in order to halve and double MTT measured during the control period. At the end of each period, the percentage disappearance of the initial added substrate and the concentration and the profile of short-chain fatty acids (SCFAs), were determined. Results: In the control period, the pH of the inoculum and SCFA concentration were inversely related to MTT (P=0.0001). Individual SCFA production was also significantly related to MTT (P < 0.01). Cisapride-reduced transit time was associated with a significant rise in the concentrations of total SCFAs (P < 0.05), propionic and butyric acids (P < 0.05) and the percentage substrate disappearance (P < 0.05). Inverse relations were observed during the loperamide period. Moreover, MTT was inversely related to the percentage substrate disappearance (P < 0.001), SCFA production (P < 0.001) and butyrate production (P < 0.0005). Conclusion: Changes in MTT alter bacterial activity and modify the bacterial pathways affecting the proportion of individual SCFAs. Sponsorship: This research was supported in part by Eridania Beghin-Say and by a grant from the French Ministry for Research (Aliment Demain contract no. G 92 G 0554) Descriptors: bacteria; colon; dietary fiber; fermentation; gastrointestinal transit; volatile fatty acids, Introduction Human fecal bacteria are representative of those occurring in different regions of the large bowel, relative to the generic distribution and relative proportion of species (Moore et al, 1978). [...]

The ingestion of Bifidobacterium sp fermented milk (BFM) increases the concentration of colon bifidobacteria and the increase is unaffected by a simultaneous intake of inulin. BFM ingestion along with a placebo enhances the total and exogenous bifidobacteria levels, and reduces beta-glucuronidase activity. The ingestion of BFM with inulin increases the total and the exogenous bifidobacteria, but has no effect on beta-glucuronidase activity. Fecal total anaerobe level, pH, nitrate reductase, nitroreductase, and azoreductase activities are unaffected by BFM.

A study reveals a strong variation in the reporting of gastrointestinal symptoms after the intake of isomalt, lactitol, and maltitol in milk chocolate. The incidence and severity of symptoms such as flatulence, colic, and frequent or loose stools were found to be dose-dependent for all of the three polyols. The experience of multiple symptoms by subjects after the intake of any of the polyols in comparison with sucrose indicates that some individuals are more prone to the osmotic effect of unabsorbed polyol in the small intestine.

Healthy volunteers who consumed a indigestible bulking sweetener containing fructo-oligosaccharides (FOS) either occasionally or regularly throughout the day showed excessive flatus as the first symptom of malabsorption of these sugars. Borborygmi and bloating were observed when the consumption was more than 40 g/day while consumption of more than 50 g/day caused abdominal cramps and diarrhoea. The excretion of H2 during respiration was the same in the two groups but only six out of nine individuals showed a decrease in the excretion of H2.

The structural features of the starch fraction that escaped digestion in the small intestine were studied in six human volunteers. Two of the samples were collected by ileostomy after intake of bean flakes or potato flakes while intubation technique was used to collect samples after ingestion of high-amylose maize starch or complex high-amylose maize starch. Analyses showed that certain potentially digestible starch could reach the colon while crystalline fractions were only part of the starch that escaped digestion in the human small intestine.

Objective: In addition to non-digested nutrients, human stools contain endogenous substrates, among which bacteria are a major component, whose growth may be stimulated when more dietary nutrients are available for bacterial fermentation, as in patients with malabsorption syndrome. We assessed the energy content and composition of both stools and faecal bacteria in healthy volunteers and patients with a short bowel and colon in continuity (SBC). Our goal was to clarify the magnitude of error introduced by the faecal bacteria in the measurement of the digestibility of ingested energy and nutrients. Subjects and methods: We studied six healthy volunteers and six patients with a SBC under free oral intake. The bacterial mass of stools was isolated. In the bacterial fractions and fresh stools, calorie, fat, nitrogen and short-chain fatty acid contents were determined. The Wilcoxon signed rank or the Mann-Whitney tests were used for comparison. Results: In healthy volunteers and patients with SBC, faecal bacterial mass accounted for 44 and 35% of faecal dry weight, and contained 50 and 34% of total faecal energy. In healthy volunteers, the apparent digestibilities when corrected by bacterial constituents (88-97% according to nutrients) were significantly higher than the apparent non-corrected digestibilities (84-94%). In patients with SBC, the corrected apparent digestibilities (69-89% according to nutrients) were significantly higher than the apparent non-corrected digestibilities (54-83%). Conclusion: The error introduced by the faecal bacterial fraction when assessing the extent of nutrient digestibility is small in healthy volunteers; it is more pronounced in patients with SBC, reaching 18% for the digestibility of ingested fat. European Journal of Clinical Nutrition (2007) 61, 233-238. doi: 10.1038/sj.ejcn.1602496; published online 23 August 2006 Keywords: faecal energetic losses, bacterial mass, short bowel, digestibility, Author(s): L Achour [1]; S Nancey [2]; D Moussata [2]; I Graber [2]; B Messing [3]; B Flourie [2] Introduction In metabolic balance studies, coefficients of absorption of energy and [...]

Objective:: Faecal bifidobacteria and lactobacilli, perceived as exerting health-promoting properties, may be increased by ingestion of high-dose lactulose in humans. The effects of low and well-tolerated doses of lactulose are not well known. The aim of the study was to assess the effects of prolonged low-dose lactulose administration on faecal bifidobacteria and selected metabolic indexes potentially involved in colonic carcinogenesis. Subjects and methods:: In all, 16 healthy volunteers were included in this controlled, randomised, double-blind, parallel group trial. Participants ingested lactulose or placebo (sucrose) at a dose of 5 g b.i.d. for 6 weeks. Stools were regularly collected at baseline (d0), and after 3 (d21) and 6 (d42) weeks of sugar ingestion. Tolerance was evaluated using a daily chart. Results:: Faecal bifidobacterial counts were higher in lactulose than in sucrose group (P=0.03). Lactulose ingestion led to a significant increase in faecal bifidobacteria counts from d0 to d21 and d42 ((m[plus or minus]s.e.m.) 8.25[plus or minus]0.53, 8.96[plus or minus]0.40 and 9.54[plus or minus]0.28 log colony-forming units/g wet wt (CFU/g), respectively (P=0.048)). Placebo ingestion did not lead to any faecal bifidobacterial count change. Total anaerobes, Lactobacillus and pH were not significantly changed throughout the study in the two groups. Neither faecal bile acids nor neutral sterols were modified by lactulose. Excess flatus was more common in the lactulose group (P=0.03), but was very mild. Bloating and borborygmi did not differ between both the groups. Conclusions:: A measure of 10 g lactulose/day increases faecal bifidobacterial counts, and lactulose fulfils the criteria requested to be considered as a prebiotic. European Journal of Clinical Nutrition (2004) 58, 462-466. doi: 10.1038/sj.ejcn.1601829 Keywords: bifidobacterium, human, intestinal microflora, lactulose, prebiotic, randomised control trial, Author(s): Y Bouhnik [1]; A Attar [1]; F A Joly [1]; M Riottot [2]; F Dyard [3]; B Flourie [4] Introduction Lactulose is a synthetic disaccharide composed of galactose and [...]

A study was done to determine the small intestinal digestibility of processed corn starches in healthy humans using an intubation technique to quantify starch malabsorption of corn starches. Results show that complexed starch has better digestibility in the ileum compared to partially retrograded starch. Furthermore, significant differences were seen in the amount of undigested starch measured in normal human subjects compared to resistant starch measured in vitro. In addition, complete fermentability of starch was seen in the colon of most test subjects.