Eggs have been the source of much ado and criticism over the decades. On the one hand, they are an excellent source of protein and contain all the amino acids your body needs to build its own protein-based structures. On the other hand, they are fairly high in cholesterol and saturated fat. While the health value of saturated fat and cholesterol is hotly debated, no one disputes the importance of amino acids.
The human body uses between 20 and 22 amino acids in order to build and maintain tissues such as skin, ligaments, cartilage, muscle, hair and fingernails, as well as a enzymes and certain hormones. Consequently, amino acids are usually called the building blocks of protein. All but eight of the the amino acids can be made by the body; those eight must be obtained from the diet or else protein deficiency symptoms start to develop, such as fatigue, weakness, edema, brittle nails, hair loss, skin problems, poor immune function and mood swings.
Eggs are an excellent source of complete protein, which contains all the essential amino acids. All sources of animal-derived protein such as meat, dairy and eggs are complete, whereas most plant-derived sources are missing at least one essential amino acid. A medium-sized egg contains about 6.3 grams of complete protein, which is almost 15 percent of the recommended daily amount for adults. Furthermore, about 35 percent of the calories in an egg are derived from its protein and amino acids.
Egg Whites and Yolks
Both egg whites and yolks contain protein. In a medium-sized egg, about 3.6 grams of protein are contained in the albumen-rich white part, whereas the remaining 2.7 grams of protein exist in the cholesterol-rich yolk. In terms of essential amino acids, the egg white contains about 1.5 grams in a medium-sized example. The eight essential amino acids are known as isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
Some fat and cholesterol is needed by your body for a variety of functions, but if you are interested in low-fat sources of amino acids then look no further than egg whites. Separating the whites and yolks is fairly easy and the whites can be made into light fluffy omelets or added to sauces. If you are an athlete or especially active, you’ll need more protein and amino acids from your diet in order to build and repair muscle tissue. Eggs are a great addition to an active lifestyle because they are high in bioavailable protein and fairly cheap, but avoid consuming them raw. Slurping up raw eggs makes for great movie scenes, but in reality it increases the risk of contracting food-borne illnesses such as Salmonella poisoning.
- Advanced Nutrition and Human Metabolism; James L. Groff et al.
- The Nutribase Complete Book of Food Counts; Art Ulene
- Encyclopedia of Human Nutrition; Benjamin Caballero et al.
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.