Eggs
Eggs are excellent articles of food for nutrition and for tissue building. They have practically the same value in the diet as meat, and make a very good substitute for meat. Egg yolk in abundance is often prescribed when it is necessary to supply a very nutritious and easily assimilated diet.
Eggs consist chiefly of two nutrients—protein and fat (ten per cent.). Because they contain so large a proportion of protein they are classified as nitrogenous foods.
The yolk, which is about one-third fat, contains iron, sulphur, potassium, calcium, magnesium, and phosphorus. The white contains some fat and phosphorus. The white and the yolk contain equal quantities of protein. The white of the egg is almost pure albumin.
The dark stain made by eggs on silver is due to the sulphur.
The iron in the yolk is a valuable assistant in building red blood corpuscles.
Eggs, in common with other proteins, are changed, mostly in the stomach, into peptone. That not digested in the stomach, as is the case with other proteins, is changed in the intestine.
If the egg is old, or if its absorption is delayed in the intestine, it decomposes, producing gas, and may cause intestinal disorder. For this reason no stale egg should ever be served, especially to an invalid.
One reason why eggs disagree with some is because too much fat is eaten at the same time. Egg yolk contains fat and if much extra fat is eaten indigestion and fermentation in the intestine may result. This is particularly true in those who digest fat with difficulty.