Effect of lactulose and Saccharomyces boulardii administration on the colonic urea‐nitrogen metabolism and the bifidobacteria concentration in healthy human subjects

• Published in: Alimentary pharmacology & therapeutics Vol. 23; no. 7; pp. 963 - 974
• Main Authors: DE PRETER, V., VANHOUTTE, T., HUYS, G., SWINGS, J., RUTGEERTS, P., VERBEKE, K.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.04.2006; Blackwell
• Subjects: Adult; Bifidobacterium; Bifidobacterium - isolation & purification; Biological and medical sciences; Colon - metabolism; Colon - microbiology; Cross-Over Studies; Dietary Carbohydrates - administration & dosage; Digestive system; Dose-Response Relationship, Drug; Drug Administration Schedule; Feces - chemistry; Feces - microbiology; Female; Gastroenterology. Liver. Pancreas. Abdomen; Gastrointestinal Agents - administration & dosage; Humans; Lactulose - administration & dosage; Male; Medical sciences; Nitrogen - metabolism; Nitrogen - urine; Pharmacology. Drug treatments; Probiotics - administration & dosage; Saccharomyces; Saccharomyces boulardii; Urea - metabolism; Human; Saccharomyces boulardii; Healthy subject; Digestive system; Lactulose; Gut; Laxative; Nitrogen; Metabolism; Fungi; Urea; Ureas; Colon; Pharmacokinetics; Thallophyta
• ISSN: 0269-2813; 1365-2036
• DOI: 10.1111/j.1365-2036.2006.02834.x

Summary Background  Protein fermentation products, especially ammonia, are implicated in the pathogenesis of certain diseases. Aim  To investigate the influence of lactulose and Saccharomyces boulardii cells on the composition of the intestinal microbiota and on the metabolic fate of ammonia by means of lactose‐[15N, 15N]‐ureide. Methods  An at random, placebo‐controlled, crossover study was performed in 43 healthy volunteers to evaluate the influence of lactulose and/or S. boulardii cells either administered as a single dose or after a 4‐week intake period. Urine and faeces were collected. All samples were analysed for 15N‐content by combustion‐isotope ratio mass spectrometry. Real‐time polymerase chain reaction was applied to determine the composition of the predominant faecal microbiota. Results  A single administration of lactulose significantly decreased urinary 15N‐excretion in a dose‐dependent way. After long‐term administration of lactulose, a significant reduction of the urinary 15N‐excretion was observed, which was accompanied with a significant increase in the faecal 15N‐output, more specifically more 15N was found in the bacterial fraction. A significant rise in the Bifidobacterium population was found after lactulose intake. No significant effects were observed after S. boulardii intake. Conclusion  Dietary addition of lactulose can exert a bifidogenic effect accompanied by a favourable effect on the colonic NH3‐metabolism.