INTRODUCTION AND OBJECTIVES

The Mediterranean diet is abundant in bioactive components such as fiber and polyphenols. Some of these components have shown their ability to modulate the immune system and microbiota composition.

The goal of this study was to investigate the impact of a diet rich in polyphenols and fiber on the intestinal barrier and gut microbiota.

MATERIALS AND METHODS

Seven-week-old Wistar rats were fed either a standard diet (REF group) or a diet enriched in fiber (9%) and polyphenols (0.5%) (FPD group) for 9 weeks. Body weight and feed and water consumption were monitored throughout the study period. At the end, intestinal tissue was collected for a histological study and contents from both the cecum and small intestine were obtained for a microbiota study. In this study, diversity and taxonomy were evaluated by massive sequencing of the 16S ribosomal RNA gene.

RESULTS AND DISCUSSION

After 9 weeks of intervention, no significant changes were found in the histological structure of the small intestine. However, in cecal content, the FPD group had higher bacterial α- and β-diversity than the REF group. Additionally, the FPD group showed a different taxonomic profile. As example, the relative abundances of the Bacteroides and Breznakia genera increased whereas those of Streptococcus and Lactococcus decreased. In the case of small intestine content, there were no differences in microbiota diversity, but some differences at the taxonomic level also appeared. The differences in α- and β-diversity and in bacteria profile found between the compartments were more evident in the FPD group.

CONCLUSION

In conclusion, although a fiber- and polyphenol-enriched diet does not change the structure of the small intestine, it modulates bacterial gut microbiota composition. Further studies will be focused on the function of the intestinal microbiota and its implications on health.