Many of our foods contain protein, either in small of large amounts. Without them man could not exist, for protein foods are necessary to provide materials for the growth and repair of all body tissues.
Muscles, nerves and skin all require protein to build them up and keep them in good condition. The protein needs of children are greater in proportion to their size than the needs of adults.
This is quite easily understood, as children are growing rapidly, whereas adults have stopped growing and their chief need is for repairing tissues which have previously been formed but broken down.
An expectant or nursing mother will also require more protein than the average adult.
- Children ages 1 – 13 ⇒ 13 – 34 grams of protein per day.
- Boys & Girls 14 – 18 ⇒ 46 – 52 grams of protein per day.
- Adults 19+ ⇒ 46 – 56 grams of protein per day.
First and Second Class Proteins
Protein foods are divided into two classes —those which provide first class and those which provide second class proteins.
First-class proteins are so called because they are used more efficiently by the human body than the second-class. They are, in general, the proteins from animal sources— milk, cheese, meat, fish poultry and eggs.
The second-class proteins, on the other hand, are those obtained in bread and cereals, nuts, legumes. vegetables and fruit. Second class proteins may be quite useful in the diet, but they are best when used to augment the first-class protein foods.
It does not matter from a health point of view, how much protein a day is included in the diet. An excessive amount is not harmful. On the other hand it is unnecessary.
When the body has used all the protein it needs for building and repairing, the rest of it is made available as a source of energy.