Page:The Road to Wellville (1926).djvu/22

 The body builders are the proteins, mineral salts, and water. They are the substances from which the body’s tissues are made. The body’s tissues include all the materials of the body. Muscles, nerves, bones, and blood are body tissues. Therefore it is imperative that protein, mineral salts, and water be supplied by food, in amounts large enough to make up for that used each day.

The proteins are complex, nitrogenous substances. They are absolutely essential to the growth and maintenance of our body tissues. Some of them have a greater potential building and repair value than others, so they must be selected with care.

All living tissue, whether of plants or animals, contains protein. Consequently, all foods not too thoroughly refined in manufacture possess protein in varying amounts.

But it is from animal sources that we obtain foods with proteins in largest amounts and in the form to do us the most good. Proteins in milk, eggs, meat, and fish are much like those in the human body, and so we can build proteins from these foods easiest into our own body tissues. However, plant proteins may be used to supplement proteins from animal sources.

An excellent source of plant proteins is found in cereals, especially in wheat.

Proteins cannot be stored up in the body to be requisitioned as needed. If there is no work for them to do, they are immediately rejected. This increases the burden upon the kidneys and may promote intestinal