Modulation of gut microbiota by a synbiotic food

Diet is a major factor in maintaining a healthy gastrointestinal tract, and this has triggered the development of functional food containing probiotic and/or prebiotic components intended to improve the host’s health via modulation of the gut microbiota. Molecular techniques based on the analysis of the rRNA gene sequences provide powerful tools to reveal the phylogenetic diversity of the microorganisms found in complex ecosystems, including the gut microbiota. In this study, we monitored the effects of a 30-days administration of a symbiotic food, containing Bifidobacterium longum, Lactobacilus helveticus and FOS, on the faecal microbiota of 20 healthy human subjects. For this purpose, PCR-DGGE analysis of 16S rRNA genes was used to detect possible changes in the overall bacterial composition. Cluster analysis of DGGE patterns highlighted that inter-individual differences were higher than the differences detected among the time-points of the feeding study. Statistical and Principal Component Analyses of the DGGE band intensities showed that the symbiotic consumption did not significantly alter the bacterial communities structure, suggesting a stabilizing impact on the microbiota. Subsequent analysis with real-time PCR indicated an increase in the amounts of B. longum and L. helveticus species, suggesting the capability of these probiotic strains to colonize the gut ecosystem.