Influence of Long-Term Administration of Lactulose and Saccharomyces Boulardii on the Colonic Generation of Phenolic Compounds in Healthy Human Subjects

Abstract

Objective: Proteins are degraded in the colon by bacterial fermentation into potentially toxic metabolites such as phenolic compounds. The aim of the present study was to investigate whether long-term administration of lactulose or Saccharomyces boulardii cells would result in a lower protein degradation. In addition, the influence of a long-term dietary intake on different gastrointestinal parameters was investigated.

Methods: The effect of long-term intervention of the substrates was evaluated in a randomized, cross-over study in 43 healthy volunteers. At the start of the study and at the end of each 4-week treatment period, urine was collected during 48 h in different fractions and faeces during 72 h. Breath test samples and blood samples were taken to study gastrointestinal parameters.

Results: No influence of long-term administration of both substrates was found on GE, OCTT and serum lipids. A significant decrease in small intestinal permeability was found after long-term dietary intervention with lactulose. Long-term administration of lactulose significantly decreased urinary p-cresol excretion, but did not lower fecal p-cresol excretion. No significant effects were observed after S. boulardii intake.

Conclusion: The results obtained in present study have indicated that colonic amino acid fermentation can be reduced by the administration of lactulose as a fermentable carbohydrate.

• p-cresol
• lactulose
• S. boulardii
• gastro-intestinal parameters

This work was supported by IWT-Vlaanderen, Brussels, Belgium (GBOU project nr. 010054). The authors also acknowledge the financial support from the Fund for Scientific Research-Flanders and the University Research Councils. The company Biodiphar (Dübendorf, Switserland) was acknowledged for providing the substrates.

L. De Vuyst (Research Group of Industrial Microbiology, Vrije Universiteit Brussel, Brussel, Belgium), G. Huys (Laboratory of Microbiology; Universiteit Gent, Gent, Belgium), J. Swings (BCCM™/LMG Bacteria Collection, Universiteit Gent, Gent, Belgium) and B. Pot (Bacteriology of Ecosystems, Institut Pasteur de Lille, Lille Cedex, France), as scientific partners of the GBOU project nr. 010054, are acknowledged for providing scientific comments.