Chap. 11 



FOODS AND NUTRITION 



169 



Non-food I I 

 Foodstuff 



Foodsfuff 



FotQ 

 Carbohydrate 



Protein 



Mineral 



Minerals 



Calcium [ 

 Phoiphorut ^^ 

 Iron 



Fig. 11.1. Fats, carbohydrates, proteins, and minerals are contained in most 

 food but in different proportions. (Reprinted from Food for Life edited by R. W. 

 Gerard, by permission of The University of Chicago Press. Copyright 1952.) 



basic elements are carbon, hydrogen, oxygen, nitrogen, sulfur, and phos- 

 phorus. The protein molecule is made up of amino acids of which at least ten 

 are essential to life. The simplest one known is glycine (H5C2O2N). All 

 growth and repair of the body is dependent upon proteins, but they must be 

 thoroughly digested into amino acids before they can be used. Fish protein 

 does not repair the tissues of cats or increase the growth of kittens until it is 

 thoroughly disorganized from its previous character. The body stores no pro- 

 tein. But after the removal of its amino group (NH^) the remainder of an 

 amino acid may be converted into glucose and used as food or changed to 

 glycogen and stored in cells as starch is stored in a potato. 



Carbohydrates. The familiar carbohydrates are starches and sugars. They 

 are made up of the elements carbon, hydrogen, and oxygen, with the hydro- 



