There are a number of carotenes, including beta-carotene and one of the benefits of fruits and vegetables is in the carotene content. Another carotene is lutein, which has been shown to be of protective benefit in age-related macular degeneration (ARMD). ARMD is inversely related to lutein levels in our diets, blood, and the macula (the back of the eye that deteriorates in macular degeneration) of our eyes. One idea is that lutein forms a blue light filter to protect deeper layers of the eyes from light damage and another idea is that lutein acts as an antioxidant.
Lutein is a type of carotenoid found in food, especially in spinach, kale and broccoli, and the lutein of egg yolks is highly absorbable in humans. The amount of lutein available from egg yolks is increased as much as 5 times in eggs from chickens that have been given extra lutein.
This paper deals with the availability of the lutein consumed for use in the human body. Six milligrams of lutein were administered to a group of men in various ways: In eggs, as lutein powder, as lutein ester supplements, and as spinach. The doses were given in test meals in the form of frittatas. Women were not included in this study since the menstrual cycle alters carotenoid blood levels.
The results of the blood tests showed that lutein is absorbed best from lutein fed chicken eggs as compared to regular eggs, supplemental lutein, and spinach. The absorption of the egg lutein may due to enhancement by cholesterol. The lutein appears in the egg yolk in the area of cholesterol, lipids, triglycerides, and phospholipids.
CONCLUSION: Lutein bioavailability from eggs is better than from lutein powder, lutein ester supplements or from spinach. Absorption from sources other than eggs does not vary much. Eggs from lutein fed chickens can have as much as five times the normal egg lutein.