92 



FOOD NUTRIENTS 



when oxidized, can be used as fuel for the release of energy, is a 

 nutrient. The term nutrient is frequently used to denote the 



Malnutrition exists among plants as well as animals. Many different minerals are essen- 

 tial for the best growth and development of plants. When soil is properly fertilized, it con- 

 tains all the essential mineral matters. Note the relation of minerals to plant growth. 



whole food, but foods are really made of combinations of nutri- 

 ents. The energy which was originally stored in the food by the 

 plant during the process of photosynthesis, is released from the 

 food during the oxidation process in the body. This stored 

 energy is set free from the food in some active form ; such as, 

 muscular energy, chemical energy, heat energy, or nervous energy. 

 When sugars and fats are burned, either over a fire or in the body, 

 waste products, carbon dioxide and water, are formed ; when pro- 

 tein is burned in the body, nitrogenous wastes, containing some 

 urea and uric acid, are formed in addition to carbon dioxide and 

 water. All foods do not yield the same amounts of energy. The 

 oxidation of those foods in which sugars and fats are concentrated 

 in the greatest amounts, yields the most energy with the least 

 amount of waste. The best fuel nutrients are sugars and fats, 

 and the growth or building nutrients are proteins, salts, and water. 

 When the diet contains an insufficient amount of sugars and 

 fats, some of the proteins may be oxidized for the release of energy. 

 But proteins give off great amount of wastes which the body 

 usually has difficulty in disposing of effectively. 



