Sucralose and the Gut–Immune Axis: Emerging Evidence Linking Dysbiosis, Barrier Alterations, and Implications for Colitis and Colorectal Cancer Immunotherapy

T-cell fitness and reduce responsiveness to immune checkpoint inhibitors through microbiome-dependent mechanisms involving altered arginine and citrulline metabolism. Human studies further indicate that sucralose can modify gut and oral microbiome composition and influence metabolic responses, although these effects appear heterogeneous and context-dependent. Overall, the current literature suggests that sucralose may act as a modifier of microbiome-immune interactions in susceptible settings, but most mechanistic evidence remains preclinical, and human data are still insufficient to establish causality. These findings highlight the need for prospective studies to determine whether sucralose-associated microbial and immune alterations translate into clinically meaningful effects in colitis, CRC, and immunotherapy response.