588 IX. CAROTENOIDS AND VITAMINS A 



In the case of the mink, it is believed that the vitamin A requirement is 

 somewhat less than that of the fox.^''^^ 



(Z) Man. In the case of human subjects, the dark adaptation test has 

 been the most widely accepted method for the evaluation of the \dtamin A 

 requirement. Lewis and Haig^" gave a figure of 25 I.U. of vitamin A/kg. 



Table 12 



The Recommended Daily Allowances of Vitamin A by the 

 Food and Nutrition Board of the National Research Council" 



« Adapted from Recommended Daily Allowances, Food and Nutrition Board, National 

 Research Council, Publ. No. 302, 1-36, revised, 1953; cited by K. E. Mason, Require- 

 ments of Human Beings, in W. H. Sebrell, Jr., and R. S. Harris, The Vitamins, Vol. I, 

 Academic Press, New York, 1954, p. 173. 



'' Based upon the assumption that two-thirds of the intake is provided as carotene, 

 and that carotene has one-half or less than one-half of the biologic value of vitamin A. 



body weight for infants, while Lewis and Bodansky^"^ cited figures of 100 

 to 200 I.U. of \atamin A/kg. body weight when blood levels were the criteria. 

 In the case of adults, the vitamin A requirements per kg. body weight ob- 

 served by the use of growth and dark adaptation tests were given as 31 

 I.U.,1"^'' 47 to 57 I.U.,^^^ and 81 I.U.^^* (dark adaptation only). Hume 

 and Krebs^^* cited as the twenty-four-hour requirement for adults a value 

 of 2500 I.U. based upon dark adaptation, plasma levels, and liver storage. 

 The vitamin A requirements of human subjects were reviewed by Mason. ^^^ 

 The daily allowance recommended by the National Research CounciP"^ 



>"3 J. M. Lewis and 0. Bodansky, Proc. Soc. Exptl. Biol. Med., 62, 265-266 (1943). 

 10" K. H. Wagner, Z. physiol. Chem., 264, 153-188 (1940). 



lo'^ Anonymous, Recotnrnended Dietary Allowances, Nat. Research Council, Food and 

 Nutrition Board, Publ. No. 302, 1-36 (1953). 



