Breakthrough Discovery by University of Chicago Researchers
Researchers at the University of Chicago have made a groundbreaking discovery regarding zeaxanthin, a carotenoid primarily recognized for its role in eye health. Their study, published in Cell Reports Medicine, suggests that zeaxanthin may also bolster the immune system’s ability to combat cancer by enhancing the effectiveness of immune cells.
Jing Chen, Ph.D., Janet Davison Rowley Distinguished Service Professor of Medicine and the study’s senior author, stated, “We were surprised to find that zeaxanthin, already known for its role in eye health, has a completely new function in boosting anti-tumor immunity. Our study shows that a simple dietary nutrient could complement and strengthen advanced cancer treatments like immunotherapy.”
Mechanism of Action
The research builds on extensive investigations into how various nutrients affect the immune system. By utilizing a comprehensive blood nutrient library, the researchers identified zeaxanthin as a compound that directly enhances the functionality of CD8+ T cells—essential immune cells responsible for destroying tumor cells. These T cells depend on a molecular construct known as the T-cell receptor (TCR) to identify and attack abnormal cells.
The study revealed that zeaxanthin stabilizes and reinforces TCR complex formation on CD8+ T cells when interacting with cancer cells. This interaction results in heightened intracellular signaling, leading to increased T-cell activation, production of cytokines, and enhanced tumor-killing capabilities.
Enhancement of Immunotherapy
In mouse models, zeaxanthin supplementation was associated with reduced tumor growth. Importantly, when used alongside immune checkpoint inhibitors—a revolutionary class of immunotherapy—zeaxanthin significantly amplified anti-tumor effects compared to immunotherapy alone. In tests involving human T cells engineered to recognize specific tumor antigens, zeaxanthin treatment also enhanced the ability of these cells to attack melanoma, multiple myeloma, and glioblastoma cells in laboratory settings.
Chen remarked, “Our data show that zeaxanthin improves both natural and engineered T-cell responses, which suggests high translational potential for patients undergoing immunotherapies.”
Safety and Accessibility of Zeaxanthin
Zeaxanthin is available as an over-the-counter supplement for eye health and is naturally present in various vegetables, including orange peppers, spinach, and kale. It is both affordable and widely accessible, exhibiting a strong safety profile that allows for its potential use as a complement to cancer therapies.
This research further underscores the significance of a balanced diet. Chen’s previous studies have indicated that trans-vaccenic acid (TVA), a fatty acid from dairy and meat sources, also enhances T-cell activity but operates through a distinct mechanism. The findings suggest that nutrients from both plant and animal origins may offer complementary advantages for immune health.
The Path Forward
While the findings are promising, the researchers caution that the research is in its initial stages. Much of the data derives from laboratory experiments and animal studies, highlighting the need for clinical trials to establish whether zeaxanthin supplements can effectively improve outcomes for cancer patients.
Chen expressed optimism about future research, stating, “Our findings open a new field of nutritional immunology that looks at how specific dietary components interact with the immune system at the molecular level. With more research, we may discover natural compounds that make today’s cancer therapies more effective and accessible.”
More information can be found in the study by Freya Q. Zhang et al, titled “Zeaxanthin augments CD8+ effector T cell function and immunotherapy efficacy,” published in Cell Reports Medicine in 2025.
