What are lutein, zeaxanthin, and beta-carotene?

Lutein, zeaxanthin, and beta-carotene belong to a family of nutrients known as carotenoids. Carotenoids are made by plants and are enriched in green leafy vegetables. They can be stored in animal tissues and are found at relatively low levels in animal-based foods. In the body, beta-carotene is used to make vitamin A, which is required by the retina to detect light and convert it into electrical signals. Beta-carotene itself is not found in the eye. In contrast, lutein and zeaxanthin are found in the retina and lens, where they may act as natural antioxidants and help absorb damaging, high-energy blue and ultraviolet light

During the AREDS trial, two large trials funded by the National Cancer Institute found that beta-carotene may increase lung cancer risk among people who smoke. Lutein and zeaxanthin are in the same family of nutrients as beta-carotene and are believed to have important functions in the retina. Lutein and zeaxanthin have not been associated with increased cancer risk.

Some studies prior to AREDS2 (references 1-7) found that dietary intake of lutein, zeaxanthin and omega-3 fatty acids is associated with a lower risk of developing advanced AMD. Analysis from the AREDS2 trial suggests that lutein + zeaxanthin offers similar or better protective benefits against advanced AMD compared with beta-carotene. In the trial, participants who took an AREDS formulation containing lutein + zeaxanthin lacking beta-carotene had an 18% lower risk of progressing to advanced AMD compared with those who took AREDS containing beta-carotene (no lutein or zeaxanthin). Among participants who had the lowest dietary intake of lutein and zeaxanthin, those who took AREDS with lutein + zeaxanthin had a 26% lower risk of progressing to advanced AMD compared to participants taking the original AREDS formula.

Info via nei.nih.gov