Correlation between intestinal microbiota and urolithin metabolism in a human walnut dietary intervention

• Published in: BMC microbiology 2024-11, Vol.24 (1), p.476-10, Article 476
• Main Authors: Liu, Huijia, Birk, John W, Provatas, Anthony A, Vaziri, Haleh, Fan, Nuoxi, Rosenberg, Daniel W, Gharaibeh, Raad Z, Jobin, Christian
• Format: Article
• Language: English
• Subjects: 16S RNA gene sequencing; Adult; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Bacteria - metabolism; Cancer; Clinical study; Colonoscopy; Composition; Coumarins - metabolism; Diet; Diet - methods; Dietary supplements; DNA sequencing; Ellagic acid; Feces; Feces - microbiology; Female; Gastrointestinal Microbiome; Gene sequencing; Health aspects; Human gut microbiota; Humans; Inflammatory bowel disease; Intestinal microflora; Juglans; Lachnospiraceae; Longitudinal Studies; Male; Metabolism; Metabolites; Microbiota; Microbiota (Symbiotic organisms); Microorganisms; Middle Aged; Nuts; Polyphenols; Prostate; RNA, Ribosomal, 16S - genetics; Tumors; Urolithin; Walnut
• ISSN: 1471-2180; 1471-2180
• DOI: 10.1186/s12866-024-03626-5

This study is to investigate the relationship between the intestinal microbiota and urine levels of the ellagic acid-derived polyphenols, the urolithins, in a cohort of subjects following a three-week walnut dietary intervention. We longitudinally collected fecal and urine samples from 39 subjects before and after walnut consumption (2 oz per day for 21 days). 16S RNA gene sequencing was performed on fecal DNA to study the association between microbiota composition and the levels of nine urolithin metabolites, which were measured using UHPLC/Q-TOF-MS/MS. Fecal microbial composition was found to be significantly different between pre- and post-walnut intervention (beta diversity, FDR-p = 0.018; alpha diversity, p = 0.018). Roseburia, Rothia, Parasutterella, Lachnospiraceae UCG-004, Butyricicoccus, Bilophila, Eubacterium eligens, Lachnospiraceae UCG-001, Gordonibacter, Paraprevotella, Lachnospira, Ruminococcus torques, and Sutterella were identified as the 13 most significantly enriched genera after daily intake of walnuts. We observed 26 genera that were significantly associated with 7 urolithin metabolites, with 22 genera positively correlating after walnut supplementation (FDR-p ≤ 0.05). PICRUSt analysis showed that several inferred KEGG orthologs were associated with 4 urolithin metabolites after walnut intake. In this study, we found that walnut supplementation altered urolithin metabolites, which associates with specific changes in bacterial taxa and inferred functional contents.