Lutein is a xanthophyll and one of approximately 600 known naturally occurring carotenoids. Lutein is produced by plants, and subsequently is found in high quantities in green leafy vegetables such as spinach, kale and yellow carrots. 

If though its name is derived from the latin word for ‘yellow’, Lutein has a reddish-yellow natural color.  It is used in the food and feed industry mainly as a colorant for food products and animal derived products. 

A common application in the feed industry is the adding Lutein to poultry feed in order to add coloring to the egg yolks. Fish farmers also tend to add Lutein to the feed to color the fish flesh more like wild naturally grown fish.