Iron is a necessary building material. An iron-poor diet means a poor quality of blood, weakened tissues, and a rundown body. Many dietaries are poor in iron.

The most valuable iron foods are: green vegetables, the most valuable source; fruits and vegetables in general; breakfast foods and breads made from meals which include the whole cereal grain, the cheapest source; eggs, which are excellent but expensive; meat, rich in iron, but the value of its iron has been questioned.