Lutein and zeaxanthin, found together in many vegetables, are potent antioxidants. In humans, they occur in high concentrations in the eye, including the lens, retina, and macula. For that reason, lutein and zeaxanthin are thought to be crucial to healthy vision.
Eye-related benefits: Lutein and zeaxanthin protect the eyes from harmful high-energy light waves, such as some ultraviolet rays in sunlight. Studies suggest that high levels of lutein and zeaxathin in eye tissue are associated with better vision, especially in dim light or where glare is a problem. Diets rich in these two antioxidants appear to protect against age-related eye diseases. For example, one study found that people with diets high in foods rich in zeaxanthin -- particularly spinach, kale, and broccoli -- are up to 50% less likely to develop cataracts. A major study (called AREDS2) has shown that supplements containing lutein and zeaxanthin can slow the progression of macular degeneration if you already have it. A test called macular pigment optical density is now being used by eye care specialists to measure levels of lutein and zeaxanthin in eye tissue.
Note: Many studies combined lutein and zeaxanthin with other nutrients, such as vitamins C and E. It's possible that the combination of nutrients may be more helpful than any single nutrient.
Recommended daily allowance: No RDA has been set for lutein or zeaxanthin.
Recommended level for eye health: The American Optometric Association recommends 10 mg/day of lutein and 2 mg/day for zeaxanthin.
Safe upper limit: Researchers have not set an upper limit for lutein or zeaxanthin.
Potential risks: Lutein and zeaxanthin in excess may turn the skin slightly yellow. Research seems to show that using up to 20 mg of lutein daily is safe.
Foods with lutein and zeaxanthin:
Kale (1 cup) 23.8 mg
Spinach (1 cup) 20.4 mg
Collard greens (1 cup) 14.6 mg
Turnip greens (1 cup) 12.2 mg
Corn (1 cup) 2.2 mg
Broccoli (1 cup) 1.6 mg