Eggs Nutrient Content

Eggs are an excellent source of many nutrients - protein, fat, vitamins, minerals, and water - although they contain very little carbohydrate or fiber. An average large egg provides about 75 calories (kcal), primarily from fat and protein.

Protein. One large egg contains approximately 7 grams of complete protein - 4 grams from the white and 3 from the yolk. As a life-sustaining protein, the quality of protein in eggs is so high that it has become the standard by which researchers rate all other foods.

Fat. One egg yolk contains approximately 5 grams of fat, predominantly in the form of triglycerides, phospholipids, and cholesterol. The fat is approximately 47 percent monounsaturated (2 grams), 37 percent saturated (slightly under 2 grams), and 16 percent polyunsaturated (slightly under 1 gram).

Egg yolks are high in cholesterol, averaging 213 mg in a large egg. Dietary cholesterol has been reported by some researchers to increase blood cholesterol. As a result, the American Heart Association recommends no more than 100 mg of dietary cholesterol be consumed for every thousand calories (kcal), which generally limits egg consumption to no more than four egg yolks per week. Despite the dietary focus on lowering fat and cholesterol, eggs are not always easily replaced in recipes, and consumer surveys show that the amount of fat often determines whether or not a food is acceptable. Commercial food processors have also tried various methods to reduce the amount of cholesterol found in foods.

Vitamins and Minerals. Eggs are rich in certain vitamins and minerals. They are one of the few foods containing all the fat-soluble vitamins - A, D, E, and K. An egg yolk provides at least 10 percent of the RDI for each of these fat-soluble vitamins. Certain water-soluble B vitamins, found primarily in the white, are also supplied by the egg in relatively high RDI percentages: 25 percent of vitamin B₁₂, 15 percent each of riboflavin (B₂) and biotin, 12 percent of folate, and 11 percent of pantothenic acid.

In addition, eggs are a source of several minerals, especially selenium, iodine, zinc, iron, and copper. Unfortunately, the iron in egg yolks is not very available because it binds to phosvitin, an egg protein that inhibits absorption. When eggs are overcooked, the iron in the yolk interacts with the small amount of sulfur found in the egg white to produce ferrous sulfide, which causes a characteristic strong off-odor.