Vitamin C.

An egg is really three separate foods, the whole egg, the white, and the yolk, each with its own distinct nutritional profile. A whole egg is a high-fat, high-cholesterol, high-quality protein food packaged in a high-calcium shell that can be grounded and added to any recipe. The proteins in eggs, with sufficient amounts of all the essential amino acids, are 99 percent digestible, the standard by which all other proteins are judged.