Protein:
Eggs are an excellent source of protein. Egg protein is of high biological value as it contains all the essential amino acids needed by the human body. Eggs therefore complement other food proteins of lower biological value by providing the amino acids that are in short supply in those foods. 12.5% of the weight of the egg is protein and it is found in both the yolk and the albumen. Although protein is more concentrated around the yolk, there is in fact more protein in the albumen.
On the evaluation scale most commonly used for assessing protein, egg is at the highest point, 100, and is used as the reference standard against which all other foods are assessed.
Vitamins:
Eggs contain most of the recognised vitamins with the exception of vitamin C. The egg is a good source of all the B vitamins, plus the fat-soluble vitamin A. It also provides useful amounts of vitamin D, as well as some vitamin E.
Minerals:
Eggs contain most of the minerals that the human body requires for health. In particular eggs are an excellent source of iodine, required to make the thyroid hormone, and phosphorus, required for bone health. The egg provides significant amounts of zinc, important for wound healing, growth and fighting infection; selenium, an important antioxidant; and calcium, needed for bone and growth structure and nervous function. Eggs also contain significant amounts of iron, the vital ingredient of red blood cells, but the availability of this iron to the body is uncertain.