Eggs provide some of the highest-quality protein available at just 75 calories per egg. In fact, the quality of egg protein is so high that scientists frequently use eggs as the standard for measuring the protein quality of other foods. One egg provides 6 grams of protein, or 12% of the Recommended Daily Value. While many people think the egg white has all the protein, the yolk actually provides nearly half of it.
Energy value of eggs A medium egg has an energy value of 78 kilocalories (324 kilojoules) and the consumption of one egg daily would contribute only around 3% of the average energy requirement of an adult man; 4% for an adult woman. With their significant protein, vitamin and mineral content and relatively low saturated fat content, eggs are a valuable component in a healthy diet.
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.
Carbohydrate and dietary fibre Eggs contain only traces of carbohydrate and no dietary fibre.
Fat 11.2% of the egg content is fat. The fat of an egg is found almost entirely in the yolk; there is less than 0.05% in the albumen. Approximately 17% of an eggâ€™s fatty acids are polyunsaturated, 44% monounsaturated and only 32% saturated.
Â Cholesterol Cholesterol and Lecithin are fat-like substances and are essential to the structure and function of all cells in the body. Cholesterol helps to maintain the flexibility and permeability of cell membranes and is also a raw material for the fatty lubricants that help to keep the skin supple. Cholesterol is essential for the production of sex hormones, cortisol, vitamin D and bile salts.Lecithin is involved in general lipid transportation in the blood and in the metabolism of cholesterol.