

FOODS AND NUTRITION 395 



foods there are substances occurring in minute quantities 

 in certain food materials, which are essential to growth 

 and complete nutrition. These substances are called 

 mtamines. If they are lacking in sufficient quantities 

 normal growth is impeded and certain diseases result. 



Ash Constituents. Mineral salts and water belong in 

 this class. The principal minerals which enter into the 

 composition of the body are salt, lime, iron, magnesia, 

 phosphorus, and potash. With the exception of com- 

 mon salt, these substances are usually taken into the 

 body only in combination with other plant and animal 

 foods. , 



Water. While water may not properly be called a food, 

 it is true that a large amount of water is needed daily, since 

 it enters into the composition of every tissue in the body 

 and is constantly being removed by the organs of excre- 

 tion. No solid matter can be absorbed and pass into 

 the blood. All food must be dissolved in order to pass 

 through the walls of the intestine, and large quantities 

 of water are needed for the process of digesting the food. 

 "Drink plenty of water every day " is an excellent health 

 rule. 



Beverages. - - Tea and coffee are in no sense foods, 

 since what proteins and carbohydrates they contain are 

 not capable of being dissolved and used by the body. 

 Chocolate and cocoa have real food value. All of these 

 drinks are stimulants of varying strengths and serve 

 to increase mental and physical alertness. The stimu- 

 lating effects of chocolate and cocoa, however, are small 

 as compared with the effects of tea and coffee. The 

 stimulant in tea is called theine ; in coffee, caffein ; in 

 chocolate and cocoa, theobromine. Tea also contains 

 another harmful substance called tannin, which inter- 



