A Supplement Best Known For Promoting Eye Health May Have Cancer Fighting Benefits

Cancer accounts for more than a half-million deaths annually (via National Cancer Institute). Fortunately, science keeps looking for innovative ways to help people reduce their risk of developing cancer as well as send active cancer into remission. A 2025 study in Cell Reports Medicine indicates that a supplement known for protecting eye health may turn out to be a valuable (and hitherto unrecognized) tool in the cancer fight.

The supplement is called zeaxanthin, a carotenoid that occurs naturally in many colorful foods, especially orange peppers and egg yolks. Because it's a carotenoid, it carries antioxidant properties, meaning it can generally help your body avoid (or recover from) damage caused by oxidative stress. (Here's everything you've ever wondered about antioxidants, explained.)

Doctors frequently prescribe zeaxanthin for use in patients with the age-specific eye condition called macular degeneration to preserve their existing vision. However, if the study findings prove to hold merit, zeaxanthin also may support a specific type of human body cell that's proving to be critical in beating cancer.

In cancer treatments that rely on immunotherapy, CD8+ T-cells are used to hunt down and destroy cancer. As the researchers found in the 2025 study, zeaxanthin appeared to amplify the natural anticancer properties of CD8+ T-cells in laboratory and animal model experiment conditions. Consequently, if the inherent capabilities of these particular cells can be enhanced, they can be more effective in causing cancer to go into remission. (Read what it means when cancer is in remission.)

Dr. Jing Chen, who led the study, described surprise at finding a new function for zeaxanthin, noting that the data "show that zeaxanthin improves both natural and engineered T-cell responses, which suggests high translational potential for patients undergoing immunotherapies" (via Science Daily). Although immunotherapy treatments like chimeric antigen receptor (CAR) T-cell therapy and monoclonal antibodies are new, they have become more prevalent options for treating a variety of cancers.

This evidence could position zeaxanthin as a useful complementary agent to buoy immunotherapy outcomes. What's especially good about this news is that zeaxanthin foods and supplements are plentiful. 

According to a 2020 review in Nutrients, some of the foods with the richest amounts of zeaxanthin aside from the previously named orange peppers and egg yolks include goji berries (280,000 micrograms per 100 grams), corn (105 micrograms per 100 grams), and spinach (75 micrograms per 100 grams). (Read about the real health benefits of goji berries.)

Another advantage to taking zeaxanthin with your doctor's approval is that it tends to be well-tolerated. If you determine that you need a supplement and you're not taking diabetes medications (zeaxanthin may induce hypoglycemia, which is low blood sugar), taking doses of 2 milligrams daily seems to be safe for most people. Just be sure to schedule your zeaxanthin pills with a fatty meal to encourage higher absorption.