A new study indicates that the artificial sweetener sucralose (Splenda) may reduce the effectiveness of anti-PD-1 immunotherapy in cancer by altering the gut microbiome and impairing T-cell function.
In patients with melanoma and lung cancer, higher sucralose intake was linked to lower response rates and shorter progression-free survival, even after adjusting for other factors. Supporting this, mouse experiments showed that sucralose-fed animals had larger tumors, shorter survival, and poor responses to anti-PD-1 therapy. The effect was driven by changes in gut bacteria, which increased arginine breakdown, an amino acid essential for T-cell energy and cancer-fighting ability. Restoring arginine with citrulline or transferring healthy gut bacteria reversed resistance.
These findings suggest that high sucralose consumption may undermine immunotherapy effectiveness. They also highlight the gut microbiome and diet as potentially critical factors in cancer treatment outcomes, pointing to the importance of nutritional guidance for patients undergoing immunotherapy.