(P08-018-25) trnL Metabarcoding - A Molecular Tool to Evaluate Plant Intake and Its Association With Gut Microbiome and Plasma Metabolome

Objectives: Accurate assessment of food intake is essential for nutritional research. This study aimed to utilize a novel DNA-based methodology to characterize plant intake from fecal samples in individuals without dietary records and to investigate its associations with the gut microbiome and plasma metabolome.

Methods: Fecal and blood samples were collected from 18 adult males at two time points as part of a previous dietary intervention that evaluated intestinal microbiota diversity (16S rRNA sequencing) and untargeted plasma metabolomics (LC-MS). Diet was retrospectively determined from stored fecal samples using amplicon sequencing of the trnL-P6 marker. Univariate and multivariate analyses were conducted to assess the relationships between diet, gut microbiome, and metabolome.

Results: A total of 89 plant taxa were identified in the fecal samples. The number of taxa per sample ranged from 16 to 35. The dominant taxa detected corresponded to the most commonly consumed plants in Colombia. Samples with greater plant richness exhibited significantly higher microbial richness (Spearman’s rho = 0.53, p=0.001). Furthermore, an individual’s plant intake was significantly correlated with their gut microbiome composition (Procrustes, p = 0.005). While the plasma metabolome was significantly associated with the gut microbiome composition (Procrustes, p = 0.025), no significant correlation was observed between plant intake and plasma metabolome (Procrustes = 0.72, p = 0.37). However, the sPLS-DA approach revealed significant associations for all three cases (p < 0.001), enabling the identification of specific relationships among the evaluated factors. Notable pairwise associations between the metabolome and plant taxa were observed, including primary metabolites (e.g., amino acids) and secondary metabolites (e.g., polyphenol catabolites).

Conclusions: Fecal trnL metabarcoding effectively characterized plant intake in a cohort of healthy men without dietary information, revealing significant correlations between plant intake, metabolome and gut microbiome diversity and composition. Our findings highlight the utility of molecular markers as reliable alternatives for dietary assessment, and the complex interactions between diet, gut microbiota, and metabolism.

Funding Sources: Vidarium and the Colombian Ministry of Science (Ctr. 80740-318-2021)