Lutein

Lutein is a xanthophyll carotenoid, a fat-soluble yellow pigment found in high concentrations in green leafy vegetables (such as kale and spinach), egg yolks, and marigold flowers. It is one of the only two carotenoids, alongside zeaxanthin, that selectively accumulate in the human retina and brain. Because the human body cannot synthesize lutein internally, it is considered a 'conditional' essential nutrient that must be obtained through diet or supplementation.