Scientists at the University of Chicago discovered that zeaxanthin – a pigment that gives corn and leafy greens their bright color – can help the immune system fight cancer. The study, published in Cell Reports Medicine, suggests that this inexpensive supplement might make cancer immunotherapy work better.
How Zeaxanthin Helps T Cells Attack Cancer
Researchers examined many nutrients that travel in blood. They found that zeaxanthin directly strengthens CD8+ T cells, the immune soldiers that seek out and destroy tumor cells.
These T cells use a structure called the T‑cell receptor (TCR) to spot abnormal cells. Zeaxanthin appears to keep the TCR stable when a T cell meets a cancer cell. This stability sends stronger signals inside the T cell, leading to more activation, higher cytokine release, and better killing power.
Better Results When Paired With Immunotherapy
In mouse experiments, adding zeaxanthin to the diet slowed tumor growth. The slowdown was even bigger when the mice also received checkpoint‑inhibitor drugs, a key type of immunotherapy. Together, the two treatments worked stronger than the drugs alone.
Human T cells engineered to recognize cancer markers also performed better in lab tests when zeaxanthin was present. The nutrient boosted the cells' ability to kill melanoma, multiple myeloma, and glioblastoma cells.
A Safe and Easy-to‑Find Nutrient
Zeaxanthin is already sold over the counter for eye health. It is naturally found in orange bell peppers, spinach, kale, and other colorful vegetables. Because it is cheap, widely available, and well tolerated, scientists think it could be tested quickly as a companion to cancer treatment.
This work adds to earlier findings that other foods, like dairy‑derived trans‑vaccenic acid, also support T‑cell function. Together, plant and animal nutrients may work side by side to keep the immune system strong.
What’s Next?
So far, the evidence comes from lab dishes and mouse models. Human trials are needed to confirm whether zeaxanthin can truly improve outcomes for cancer patients.
The researchers call this a new branch of “nutritional immunology,” where specific foods are studied for their direct effects on immune cells. With more research, everyday nutrients might one day help make cancer therapies safer and more effective.
The study, titled “Zeaxanthin augments CD8+ effector T cell function and immunotherapy efficacy,” was funded by the National Institutes of Health, the Ludwig Center at the University of Chicago, and the Harborview Foundation Gift Fund.