Several people have called to ask me whether they should eat the egg yolk or just the whites.
The Yolk contains most of the nutrients in an egg. In fact, the number of nutrients in an egg yolk is so comprehensive that a few egg yolks a day would offer more nutrients than a multi-vitamin. Egg Whites, on the other hand, contain far fewer nutrients.
The importance of the egg yolk and relative unimportance of the egg white is clear. The yolk contains the majority of the copper, nearly all of the calcium, iron, folate, and B6, and 100% of the vitamins A and E.
The white, on the other hand, is only useful as an added source of magnesium or protein. The simple addition of an adequate amount of meat in the diet would provide for both.
Finally, eggs are an excellent source of carotenoids. These are primarily highly absorbable forms of lutein and its partner zeaxanthin. These carotenoids accumulate in the back of the eye and appear to protect against age-related macular degeneration. All of the lutein and zeaxanthin in an egg is contained in the yolk.
Biotin or vitamin B7 was discovered in 1936 and used as a cure for egg white disease. Egg white disease was a condition caused by over consumption of uncooked egg whites which was discovered to inhibit the action of the vitamin Biotin. B7 is a water soluble vitamin, this means it cannot be stored in the body so it must be absorbed on a daily basis.
So missing out on the egg yolks means missing out on the nutrition in your breakfast. Remember this the next time you enjoy the incredible, edible egg yolk.