Lutein is a vitamin in the vitamin A family that is present in broccoli, squash and spinach, according to WebMD. It is often referred to as an "eye vitamin," as the substance is found in color pigments of the eye and is believed to protect the eyes by filtering light.
Lutein is believed to function as an essential antioxidant in the body, protecting the immune system against free radical damage that can lead to various diseases, explains All About Vision. The vitamin may also aid in protecting individuals from developing atherosclerosis, a condition in which excess fatty deposits develop in the arteries, which in turn can lead to heart attacks.
Physicians recommend that adults consume at least 6 milligrams of lutein per day in order to maintain healthy eyes, explains Bausch and Lomb. People are born with a specific amount of lutein already present in the eyes. However, the vitamin must be replenished because it is not naturally produced by the body.
Studies have shown that when luetin is taken in conjunction with vitamin E and zeaxanthin, another vitamin found in green leafy vegetables, the combination may help to minimize the risk of developing eye conditions such as age-related macular degeneration and cataracts, according to the American Optometric Association. Research has also shown that lutein and zeaxanthin help to improve symptoms in individuals who have been diagnosed with cataracts and macular degeneration.