Western Diet Linked to Severe Immunotherapy Side Effects

High-Fat Diets Fuel Severe Immunotherapy Complications

Up to 25% of cancer patients undergoing immunotherapy experience severe adverse events. New research reveals that a common Western diet loaded with low fiber, high fats, and processed carbohydrates may be to blame.

These inflammatory complications frequently force patients to halt their cancer treatments or require hospitalization.

The Clinical Toll on Quality of Life

"Immunotherapy-related adverse events are a massive problem, drastically affecting patients' quality of life," Overacre-Delgoffe explained. "In many cases, it impacts their ability to continue receiving immunotherapy or benefit from treatment."

Limitations in Prior Mouse Models

To overcome this, Dipyaman Patra, a postdoctoral researcher in the Overacre-Delgoffe lab and lead author of the study, pointed out the limitations of existing research. “Most existing mouse models rely on genetically engineered mice or experimental conditions that don’t truly capture the variability we see in patients,” Patra said.

Cellular Fragility in Regulatory T Cells

The research team fed mice a human-like Western diet for two weeks before starting checkpoint inhibitor therapy. These animals not only developed severe adverse events during treatment, but their regulatory T cells also exhibited distinct signs of fragility.

Researchers confirmed this same cellular vulnerability in regulatory T cells harvested from human cancer patients suffering from severe immune-related side effects. Patients who escaped these side effects showed no such cellular breakdown.

Dietary Shifts Reduce Inflammation

When the team worked to restore stability to these delicate regulatory T cells, the severity of the inflammatory side effects dropped significantly. Researchers achieved this stabilization in mice by specifically blocking a single immune signaling protein on the cells, switching the animals to a high-fiber diet, or administering targeted metabolite supplements.

The findings point to dietary interventions and metabolite supplementation as promising clinical strategies. These methods could reduce a patient’s susceptibility to dangerous inflammation without interfering with the underlying cancer immunotherapy or disrupting the gut microbiome.

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