By Morgan Nwanguma
A common nutrient found in everyday vegetables may help boost the body’s ability to fight cancer.
Zeaxanthin, best known for supporting eye health, is now showing promise as a powerful ally in cancer treatment. Researchers have found that it can strengthen T cells – key players in the immune system and improve the effectiveness of immunotherapy. Because it is already widely available in foods and supplements, zeaxanthin is considered safe, accessible, and a strong candidate for enhancing existing cancer therapies. The next step is to confirm these benefits in human trials.
Scientists at the University of Chicago uncovered this unexpected role for the plant-based compound. Their findings, published in Cell Reports Medicine, suggest that zeaxanthin can enhance immune responses against cancer, opening the door to a simple, nutrition-based way to improve immunotherapy outcomes.
“We were surprised to find that zeaxanthin, already known for its role in eye health, has a completely new function in boosting anti-tumour immunity,” said Jing Chen, PhD, Janet Davison Rowley Distinguished Service Professor of Medicine and senior author of the study. “Our study show that a simple dietary nutrient could complement and strengthen advanced cancer treatments like immunotherapy.”
The way Zeaxanthin Activates Cancer-Fighting T Cells
Building on years of research into how nutrients influence immunity, Chen’s team screened a wide range of compounds found in the bloodstream and identified zeaxanthin as a standout. The nutrient was shown to directly enhance the performance of CD8+ T cells – immune cells that play a critical role in recognizing and destroying cancer.
These T cells rely on the T-cell receptor (TCR) to detect abnormal or cancerous cells. The researchers discovered that zeaxanthin helps stabilize the formation of this receptor complex when T cells engage a target. As a result, internal signaling becomes stronger, leading to greater T-cell activation, increased cytokine production, and a more effective tumour-killing response.
Enhancing the Power of Immunotherapy
In mouse models, dietary zeaxanthin slowed tumour growth. The benefits were even greater when combined with immune checkpoint inhibitors – a widely used class of immunotherapy drugs. Together, the combination produced a more powerful anti-tumour effect than immunotherapy alone.
The researchers also tested human T-cells engineered to recognise specific cancer markers. In laboratory studies, zeaxanthin enhanced these cells’ ability to destroy cancer cells from melanoma, multiple myeloma, and glioblastoma, highlighting its potential to strengthen advanced cancer treatments.
“Our data show that zeaxanthin improves both natural and engineered T-cell responses, which suggests high translational potential for patients undergoing immunotherapies,” Chen said.
A Safe, Accessible Nutrient with Broad Potential
Zeaxanthin is already widely available as an over-the-counter supplement commonly used to support eye health. It also occurs naturally in foods like orange peppers, spinach, and kale. Because it is affordable, easy to access, and generally well tolerated, researchers believe it could be rapidly evaluated as a complementary addition to cancer treatment.
The findings also reinforce the broader role of diet in shaping immune function. In earlier research, Chen’s team identified trans-vaccenic acid (TVA) – a fatty acid found in dairy and meat as another compound that boosts T-cell activity through a different mechanism. Together, these discoveries suggest that nutrients from both plant and animal sources may work in tandem to strengthen the body’s immune defenses.
What Comes Next for Zeaxanthin in Cancer Care
Despite the encouraging results, the research is still at an early stage. Much of the current evidence comes from laboratory studies and animal models. Clinical trials will be essential to determine whether zeaxanthin can meaningfully improve outcomes for people undergoing cancer treatment.
“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,” Chen said. “With more research, we may discover natural compounds that make today’s cancer therapies more effective and accessible.”
The study, “Zeaxanthin augments CD8+ effector T-cell function and immunotherapy efficacy,” was backed by funds from the American National Institutes of Health, the Ludwig Centre at the University of Chicago, as well as the Harborview Foundation Gift Fund.
The other authors are: Freya Zhang, Jiacheng Li, Rukang Zhang, Jiayi Tu, Zhicheng Xie, Takemasa Tsuji, Hardik Shah, Matthew Ross, Ruitu Lyu, Junko Matsuzaki, Anna Tabor, Kelly Xue, Chunzhao Yin, Hamed R. Youshanlouei, Syed Shah, Michael W. Drazer, Yu-Ying He, Marc Bissonnette, Jun Huang, Chuan He, Kunle Odunsi, and Hao Fan from the University of Chicago; Fatima Choudhry from DePaul University, Chicago; Yuancheng Li and Hui Mao from Emory University School of Medicine, Atlanta; Lei Dong from University of Texas Southwestern Medical Center, Dallas; and Rui Su from Beckman Research Institute, City of Hope, Duarte, CA.
English