180 THE WEALTH OF THE SEA 



mine A, which prevents certain eye diseases and aids 

 in growth. For centuries it has been the custom in 

 Japan to give eel fat to children suffering from a 

 disease known as hikan, which has recently been 

 found to be caused by a lack of vitamine A. 



Shell-fish, such as oysters, clams, and lobsters are 

 of great dietary importance. Oysters contain both 

 the water-soluble vitamines B and C. When eaten 

 raw, oysters and clams are especially valuable foods, 

 for they furnish the water-soluble vitamine C, ordi- 

 narily obtained only from fresh raw fruits and 

 vegetables. 



The Place of Sea-Foods in the Diet 



The nutritive value of fish and other sea-foods has 

 already been discussed in detail. It remains, how- 

 ever, to consider specifically their place in the 

 dietary. 



A monotonous diet is dangerous, for if a person 

 always eats the same proteinaceous, fatty, and vege- 

 table foods, his diet is likely to be deficient in some 

 essential amino-acid, mineral constituent, or vita- 

 mine. A diet lacking in any one essential nutritive 

 factor is a failure ; any one taking it will suffer from 

 some form of malnutrition. The deficiency disease 

 may take a great variety of forms. Its symptoms 

 are legion, and may appear to be trifling, as for 

 example, nervousness, bad teeth, headaches, and 

 flat feet. 



No one should ever continue to eat day after day 

 exactly the same foods for breakfast, lunch, or din- 

 ner. Any satisfactory diet must be varied, and must 



