Welcome to the The Incredible Edible Egg™ Eggcyclopedia, where you can access the latest egg information from A-Z. The Eggcyclopedia was developed by the American Egg Board (AEB) on behalf of America's egg farmers who are committed to caring for their hens and producing high-quality eggs for you and your families.

Just click on any letter below to bring up a list of egg terms and their related definitions.


Both lutein and zeaxanthin are carotenoids called xanthophylls, yellow-orange plant pigments. These carotenoids have been shown to reduce the risks of cataracts and age-related macular degeneration, the leading cause of blindness in those 65 and older. Lutein and zeaxanthin accumulate in the eye’s lens and in the macular region of the retina. Scientists believe high levels of lutein and zeaxanthin in these areas may protect the eye from damage due to oxidation. Lutein and zeaxanthin are commonly found in dark-green leafy vegetables, such as spinach and kale, and are well-absorbed from egg yolk. A large egg yolk contains 252 mcg of lutein and zeaxanthin. When hens are fed a diet which includes yellow corn, alfalfa meal, corn-gluten meal, dried-algae meal or marigold-petal meal, xanthophylls are deposited in the yolks. Research has shown that, due to the egg yolk’s fat content, the yolk’s lutein and zeaxanthin may be more easily absorbed by the body than the lutein and zeaxanthin from other sources. A specific recommendation for daily consumption of these carotenoids has not yet been set.