Fiber utilizing capacity varies with Prevotella versus Bacteroides enterotypes

Abstract

The human gut microbiota is highly individualized because of the forces of diverse hosts’ genetic background, living environment and dietary habit. Population data on human gut microbiota show distinctive enterotypes (Prevotella, Bacteroides or Ruminococcus dominant) that are associated with long‐term diet patterns. Yet, enterotypes have not been linked with health status. Short chain fatty acids (SCFAs), generated by dietary fiber fermentation, are biologically active and are an important target related to colon and whole body health. Here, we were interested in understanding whether fibers produce different SCFA amounts and ratios in different enterotypes. A study was designed to explore how the different fiber structures influence gut microbiota composition and SCFA production in two enterotypes using an in vitro batch human fecal fermentation model.The dominance of Prevotella versus Bacteroides in the initial enterotypes had a large impact on SCFA products from fermentation of fibers of different types and with different chemical complexity. A single Prevotella OTU was exclusively promoted in the microbiome of the Prevotella enterotype when fed fructooligosaccharides (FOS) or sorghum or corn arabinoxylans (SAX, CAX), while in the Bacteroides enterotype different OTUs were enriched by each fiber (Lactobacillus by FOS, Bacteroides with different OTUs by SAX and CAX). SCFA production by the two enterotypes on the three fibers was substantially different. Propionate was initially 2–3 fold higher in the stool of the Prevotella compared to the Bacteroides enterotype, and had up to 4 fold higher increase with the fiber treatments. Furthermore, The total amount of SCFA generated by SAX and CAX matched at 24 h in each microbiota, but the fermentation rate varied with the simpler SAX structure fermenting fast in both enterotypes and the more complex CAX fermenting as fast as SAX in the Prevotella enterotype but much slower in the Bacteroides enterotype. Overall, the dominant fiber‐using bacteria and the type of dietary fiber together determined the SCFA profile generated by fermentation. This study shows the possibility to design fibers for future personalized medicine.