Sucralose May Undermine Cancer Immunotherapy by Disrupting Gut Microbiome

A new study from the University of Pittsburgh and UPMC Hillman Cancer Center, published in Cancer Discovery, reveals that sucralose, a common sugar substitute, may impair the effectiveness of cancer immunotherapy. Researchers found that in both patients and mouse models, high sucralose intake disrupted gut bacteria, reducing levels of the amino acid arginine, which is critical for T cell activity. This depletion weakened the response to immune checkpoint inhibitors such as anti-PD1 therapy, resulting in poorer survival outcomes.

In mice with melanoma and adenocarcinoma, sucralose consumption led to larger tumors and diminished treatment effectiveness. However, supplementation with arginine or citrulline restored immunotherapy response, suggesting a potential nutritional strategy to counteract the sweetener’s negative effects.

Analysis of 132 patients with melanoma or lung cancer showed that those consuming higher amounts of sucralose had worse outcomes. Researchers now plan clinical trials to test citrulline supplementation and evaluate other artificial sweeteners.

06-09-2025