Table 4.

Examples of gut microbiota-derived metabolites and their beneficial effects on human health

Metabolite	Pathway	Microbial agent	Health benefits
Butyrate	Carbohydrate metabolism	Clostridia; Faecalibacterium prausnitzii; Coprococcus catus; Anaerostipes hadrus	Increased intestinal barrier function; Modulate intestinal macrophage function; Suppression of colonic inflammation; Improvements in insulin sensitivity
Propionate	Carbohydrate metabolism	Blautia obeum; Coprococcus catus; Roseburia inulinivorans; Prevotella copri	Suppression of colonic inflammation; Decreased innate immune response to microbial stimulation; Protection from allergic airway inflammation; Improvements in insulin sensitivity and weight control in obese mice
Indole	Tryptophan metabolism	Lactobacillus; Bifinobacterium longum; Bacteroides fragilis	Maintenance of host-microbe homeostasis at mucosal surfaces via IL-22; Increased barrier function; Modulation of host metabolism
Indole-3-aldehyde	Tryptophan metabolism	Lactobacillus	Maintenance of mucosal homeostasis and intestinal barrier function via increased IL-22 production; Protection against intestinal inflammation in mouse models of colitis
Indole-3-propionate	Tryptophan metabolism	Clostridium sporogenes	Maintenance of intestinal barrier function and mucosal homeostasis; Increased production of antioxidant and neuroprotectant products
10-hydroxy-cis-12-octadecoate	Linoleic acid derivative (lipid metabolism)	Lactobacillus	Maintenance of intestinal barrier function; Decreased inflammation; Increased intestinal IgA production

IgA: Immunoglobulin A; IL-22: Interleukin 22.