CHAPTER XI 

 FOOD NUTRIENTS 



When broken into elements 



man is worth eighty-two cents. 



What is a food? What is the relation of a nutrient to a food? 

 What is meant by dietary requirements and dietary deficiencies? 



Since the cell is the basis of our make-up, and since these cells 

 live, grow, and work, each must have food and oxygen to carry 

 on the various life processes. The cells of the brain must have 

 food and fuel to do the part each does in the thinking process. 

 Muscle cells in the thumb and fingers must be nourished and given 

 oxygen if they are to do their work. 



What is a food ? A beefsteak includes lean meat, fat, and bone. 

 Only a part of this can be used by the body. This part is nu- 

 tritious. Potatoes contain about 70 per cent of water and vary- 

 ing amounts of starch, protein, and mineral salts. As a matter 

 of fact, they contain only about 25 per cent of nutritive material. 

 The small per cent of cellulose which makes up the cell walls has 

 no more real food value than the wood of a lead pencil. It passes 

 through the food tube, unaffected chemically. Such parts of the 

 potato are called waste. Thus we see that every food may contain 

 both nutrients and wastes. Certain of the waste materials that 

 pass through the food tract undigested, serve the real and de- 

 sirable purpose of giving bulk to the diet. 



What is a nutrient ? Any substance, such as carbohydrate, pro- 

 tein, or fat, that yields material for growth and repair of tissues or, 



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