Individual Difference in the Capacity of Gut Microbiota to Ferment Four Complex Carbohydrates from Normal to Overweight People: An <i>In Vitro</i> Study

Pectic polysaccharides can beneficially shape the human microbiota. However, individual variability in the microbial response, especially the response between normal-weight (NW) and overweight (OW) people, is rarely understood. Therefore, we performed batch fermentation using inulin (INU), commercial pectin (CP), and pectic polysaccharides extracted from goji berry (GPP) and raspberry (RPP) by microbiota from five normal-weight (NW) and five overweight (OW) donors. The degree of specificity of fiber was negatively correlated to its fermentable rate and microbial response. Meanwhile, we found that microbiota from OW donors had a stronger fiber-degrading capacity than NW donors. The result of correlation between individual basal microbiota and the fermentable rate indicated Dialister, Megamonas, Oscillospiraceae_NK4A214, Prevotella, Ruminococcus, and unidentified_Muribaculaceae may be the key bacteria. In summary, we highlighted a new perspective regarding the interactive relationship between different fibers and fecal microbiota from different donors that may be helpful to design fiber interventions for individuals with different microbiota.