A new study has raised concerns about the use of artificial sweeteners during cancer treatment, revealing that these sugar substitutes may interfere with the effectiveness of immunotherapy in some patients.

According to research published in Cancer Discovery, scientists found that a common artificial sweetener disrupted the success of immunotherapy in mice models. The sweetener, which was not named in the summary, appeared to alter immune system responses — making treatments less effective.

Lead researcher Professor Abby Overacre and her team discovered that mice consuming the artificial sweetener responded poorly to cancer-fighting immunotherapy compared to those that did not.

Arginine supplement may offer a simple solution

Fortunately, the study also suggests a potential fix: arginine, a natural amino acid. When researchers gave mice an arginine-boosting supplement, it seemed to reverse the negative impact of the artificial sweetener.

“It’s easy to say, ‘Stop drinking diet soda,’ but patients undergoing cancer treatment are already going through a lot,” researchers noted. “So we have to take care of them realistically.”

Using an arginine supplement may provide a practical workaround for patients who are reluctant or unable to eliminate artificial sweeteners from their diet.

What this means for cancer patients

Artificial sweeteners, often marketed as healthier alternatives to sugar, are commonly found in diet sodas, sugar-free snacks, and low-calorie desserts. While convenient, they may pose unintended risks for people undergoing certain cancer therapies.

The findings add to a growing body of research questioning the safety of artificial sweeteners. The World Health Organization (WHO) has previously warned that such additives could be linked to serious health conditions, including cardiovascular diseases and metabolic disorders.

The path ahead

While this research is still in early stages and based on animal models, it paves the way for future human trials to better understand how sweeteners interact with cancer treatments.

In the meantime, patients are encouraged to consult their doctors about diet choices during therapy. Researchers are hopeful that arginine supplementation could soon offer a safe, effective way to maintain dietary habits without compromising treatment.