Cancer patients who use sucralose — the artificial sweetener found in products like Splenda — may be less likely to respond to immunotherapy treatment and could face shorter survival rates. But scientists say there may be a way to reverse the damage.

Study Details

Researchers from the University of Pittsburgh and UPMC Hillman Cancer Center found that patients with melanoma and non-small cell lung cancer who consumed high levels of sucralose, often to cut calories or manage blood sugar, had weaker responses to immunotherapy.

To better understand why, the team turned to lab experiments with cancer-bearing mice.

According to Study Finds, sucralose altered the gut microbiome in a way that caused the amino acid arginine to break down. Arginine fuels T cells — immune cells that play a key role in fighting cancer. When mice were given citrulline, an amino acid that boosts arginine levels, or received gut bacteria from mice that responded well to immunotherapy, their treatment effectiveness improved.

Expert Insight

“We found that sucralose impeded the effectiveness of immunotherapies across a range of cancer types, stages and treatment modalities,” said senior author Diwakar Davar, associate professor of medicine at Pitt and a medical oncologist and hematologist at UPMC Hillman Cancer Center. “These observations raise the possibility of designing prebiotics, such as targeted nutrient supplementation for patients who consume high levels of sucralose.”

Next Steps

The researchers plan to launch a clinical trial to test whether citrulline supplements — which raise arginine levels more effectively than arginine itself — can positively influence the gut microbiome and enhance the immune response in cancer patients.

They also intend to study how other popular sugar substitutes, including aspartame, saccharin, xylitol, and stevia, may impact both the immune system and the effectiveness of immunotherapy.