There is growing interest in the crosstalk between the gut microbiome, host metabolomic features, and disease pathogenesis. The current investigation compared long–term (26 week) and acute (3 day) dietary spinach intake in a genetic model of colorectal cancer. Metabolomic analyses in the polyposis in rat colon (Pirc) model and in wild–type animals corroborated key contributions to anticancer outcomes by spinach–derived linoleate bioactives and a butanoate metabolite linked to increased α–diversity of the gut microbiome. Combining linoleate and butanoate metabolites in human colon cancer cells revealed enhanced apoptosis and reduced cell viability, paralleling the apoptosis induction in colon tumors from rats given long–term spinach treatment. Mechanistic studies in cell–based assays and in vivo implicated the linoleate and butanoate metabolites in targeting histone deacetylase (HDAC) activity and the interferon–γ (IFN–γ) signaling axis. Clinical translation of these findings to at–risk patients might provide valuable quality–of–life benefits by delaying surgical interventions and drug therapies with adverse side effects.