Regular Consumption of Lacto-fermented Vegetables has Greater Effects on the Gut Metabolome Compared with the Microbiome

The industrialization of Western food systems has greatly reduced the regular consumption of lacto-fermented vegetables (LFV). Consuming LFV may exert health benefits through the alteration of the gut microbiome, but the events and mechanisms involved remain unclear. To start understanding the possible benefits of LFV, we compared fecal microbial diversity and composition, as well as dietary habits between individuals who regularly consume LFV (n=23) and those who do not (n=24). We utilized microbial DNA amplicon sequencing (16s rRNA and ITS2) and untargeted metabolomics (LC-MS) to analyze stool samples. Study participants also provided three consecutive days of dietary data. Results show only minor effects on microbiome composition; with the enrichment of a few microorganisms potentially associated with vegetable ferments, such as _Leuconostoc mesenteroides and Rhodotorula mucilaginosa (P<0.05)_, in LFV consumers. However, LFV consumption had greater effects on the fecal metabolome, with higher abundances of butyrate, acetate, and valerate (P<0.05) and significantly greater metabolome diversity (_P<0.001_). Overall, the observations of minor changes in the fecal microbiome and greater effects on the fecal metabolome from LFV consumption warrant further investigations on the health significance of LFV as regular components of the daily diet in humans.