Enterotype-Driven Metabolic Shifts in Response to FOS: SCFA and Tryptophan Derivative Enrichment
Fructooligosaccharide (FOS) is a well-characterized prebiotic carbohydrate that resists digestion in the upper gastrointestinal tract and reaches the colon, where it serves as a nutrient source for gut microbiota. This study investigates the impact of FOS on gut microbial structure and metabolism using an in vitro fecal incubation model combined with comprehensive untargeted metabolomic analysis. Fecal samples from 19 healthy donors were collected and incubated with or without FOS for 24 hours. To address inter-individual variability, subjects were classified into two enterotypes based on bacterial dominance: 14 with a Bacteroides-dominant type (enterotype B) and 5 with Prevotella-dominant type (enterotype P). Alpha diversity, indicative of microbial richness and evenness, was significantly reduced in FOS-treated group compared to the control group for both enterotypes. Additionally, distinct gut bacterial community structures were observed in both enterotypes after FOS treatment, as shown by unweighted and weighted UniFrac distance analysis. Notably, SCFA (short chain fatty acid)-producing bacteria such as Bifidobacterium_388775 and Feacalibacterium were significantly enriched in enterotype B and found to be specific to this enterotype in response to FOS treatment. Metabolic profiling revealed a significant enrichment of tryptophan derivatives in addition to SCFAs in the FOS-treated group. Specifically, tryptophan derivatives involved in the synthesis of indole-3-aldehyde (ICA) were significantly elevated in the FOS-treated group compared to the control, a phenomenon that has received less attention compared to SCFA production. These findings highlight the enterotype-specific responses to FOS treatment and the resulting metabolic changes, emphasizing the importance of considering enterotypes in research on gut microbiome-food interactions.
Fructooligosaccharide (FOS) is a well-characterized prebiotic carbohydrate that resists digestion in the upper gastrointestinal tract and reaches the colon, where it serves as a nutrient source for gut microbiota. This study investigates the impact of FOS on gut microbial structure and metabolism using an in vitro fecal incubation model combined with comprehensive untargeted metabolomic analysis. Fecal samples from 19 healthy donors were collected and incubated with or without FOS for 24 hours. To address inter-individual variability, subjects were classified into two enterotypes based on bacterial dominance: 14 with a Bacteroides-dominant type (enterotype B) and 5 with Prevotella-dominant type (enterotype P). Alpha diversity, indicative of microbial richness and evenness, was significantly reduced in FOS-treated group compared to the control group for both enterotypes. Additionally, distinct gut bacterial community structures were observed in both enterotypes after FOS treatment, as shown by unweighted and weighted UniFrac distance analysis. Notably, SCFA (short chain fatty acid)-producing bacteria such as Bifidobacterium_388775 and Feacalibacterium were significantly enriched in enterotype B and found to be specific to this enterotype in response to FOS treatment. Metabolic profiling revealed a significant enrichment of tryptophan derivatives in addition to SCFAs in the FOS-treated group. Specifically, tryptophan derivatives involved in the synthesis of indole-3-aldehyde (ICA) were significantly elevated in the FOS-treated group compared to the control, a phenomenon that has received less attention compared to SCFA production. These findings highlight the enterotype-specific responses to FOS treatment and the resulting metabolic changes, emphasizing the importance of considering enterotypes in research on gut microbiome-food interactions.
University of California San Diego Microbiome Initiative