226 VITAMINS 



the boiling point (to destroy ascorbic acid oxidase) and cook no longer 

 than necessary, (3) use fresh fruits and vegetables immediately after 

 harvesting, (4) if the food must be stored, keep it cold and protected 

 from air as much as possible {e.g., wrapped in paper, with the original 

 husks or skins on, not cut or sliced up, etc.), (5) avoid the use of ma- 

 terials, especially copper, which catalyze the oxidation of vitamin C. 

 Many of these same principles apply equally well to the preservation of 

 other sensitive vitamins. In general, if food is so handled that its vitamin 

 C is largely retained, all other food factors will most probably be pre- 

 served also. 



Certain tissues of the body are rich in vitamin C. It is particularly 

 concentrated in the cortex of the adrenal glands, in the lens, aqueous 

 humor, and vitreous humor of the eye, and in the pituitary gland. In 

 fact, concentration seems to be correlated with metabolic activity. Al- 

 though liver contains more than other animal tissues used for food, this 

 organ does not seem to function so prominently in the storage of vitamin 

 C as it does in retaining vitamins A and D, and riboflavin. 



Requirements 



The needs of various persons for this vitamin are shown in Table 9-3, 

 from which it can be seen that relatively large amounts are required. 

 Relying upon one food source for the day's supply, one would need to 

 consume three-fourths cup of orange juice, four to five quarts of milk, 

 one-fourth pound of raw cabbage, or three-fourths pound of raw toma- 

 toes. 



THIAMINE (VITAMIN B^) 



Physiological function 



An inadequate intake of this vitamin eventually leads to the onset 

 of a disorder known in human beings as beriberi and in the experimental 

 animal as polyneuritis. There are two distinct forms of beriberi: (1) 

 the dry type, in which there is excessive muscular atrophy, anaesthesia 

 of the skin, and paralysis of the legs, arms, diaphragm, and intercostal 

 muscles; (2) the wet type, which is characterized by swelling of the arm, 

 leg, and trunk muscles; by effusion of fluid into the body cavities; by 

 congestion of the liver; and by dilatation of the heart with resultant 

 heart failure. The wet type is somewhat more common in infants, but 

 symptoms of both types frequently appear in the same patient. In 

 general, the symptoms appear first in the feet and lower parts of the 

 legs, and progress upward toward the trunk. 



It is now generally agreed that thiamine functions in the animal body 



