In Vitro Gut Microbial Metabolism of Ferulic Acid Reveals Interindividual Variability

Interindividual variability in gut microbial metabolism of 4'-hydroxy-3'-methoxycinnamic acid (ferulic acid, FA), a major phenolic acid in cereals, may influence health outcomes and nutritional guidance. We examined FA metabolism using in vitro fecal batch incubations from 18 individuals, integrating 1H NMR metabolomics with 16S rRNA amplicon sequencing. All individuals produced a shared set of FA catabolites but differed in the timing and extent of conversion. We identified metabolic signatures, including early/late FA degraders, early/late producers of key catabolites, and profiles characterized by high 3-phenylpropanoic acid and low 3-(3',4'-dihydroxyphenyl)propanoic acid, and vice versa.