When most Americans find out they have cancer, the first thing they do is prepare themselves for surgery, chemotherapy, radiation and pharmaceuticals their oncologist highly recommends. They may go get a second exam or opinion from another oncologist, and then it's off to the drip factory for the most toxic and least effective cancer therapy on the planet. What other choice do they have? Well, natural remedies that are plant-derived, that's what.

A common dietary nutrient known for protecting vision may have a surprising new role in cancer treatment. Researchers from the University of Chicago have discovered that zeaxanthin—a plant-derived carotenoid found in foods like spinach, kale, and orange peppers—can enhance the immune system's ability to destroy tumor cells. The findings, published in Cell Reports Medicine, suggest that this inexpensive, widely available compound could strengthen modern cancer immunotherapies.

New immune-boosting role for a vision nutrient – Researchers found that zeaxanthin, a carotenoid best known for eye health, strengthens CD8+ T cells, enhancing their tumor-killing capacity.

Improved cancer immunotherapy – In mouse models and lab tests, zeaxanthin supplementation slowed tumor growth and significantly enhanced the effects of immune checkpoint inhibitors and engineered T-cell therapies.

Safe, accessible, and already available – Naturally found in vegetables like orange peppers, spinach, and kale, as well as over-the-counter supplements, zeaxanthin is inexpensive, well-tolerated, and has a known safety profile, making it a strong candidate for rapid clinical testing.

Opens a new field of nutritional immunology – The findings suggest that specific dietary compounds can directly boost immune function at the molecular level, potentially making cancer treatments more effective and accessible worldwide.

Plant-based Nutrient Can Boost Immune Cells' Ability to Fight Cancer

Zeaxanthin is best known for supporting eye health, but the new study reveals a completely different function. By screening a library of blood nutrients, the research team identified zeaxanthin as a compound that boosts the activity of CD8+ T cells, key immune cells that recognize and kill cancer cells. These cells rely on a molecular structure called the T-cell receptor (TCR) to identify abnormal cells. The researchers found that zeaxanthin stabilizes the TCR complex, leading to stronger intracellular signaling, increased cytokine production, and enhanced tumor-killing power.