586 NIACIN 



the response of nicotinic acid-deficient dogs to nicotinic acid and helped 

 to maintain a more normal blood picture. Ruegamer et aZ.^"^ reported that 

 both folic acid and nicotinic acid M'ere required to obtain a response with 

 liver extract in an anemia which developed in dogs on rations which were 

 probably deficient in all three factors. Teply et a/.^^^ found an interrelation 

 between folic acid and nicotinic acid in the ceca of rats under various dietary 

 circumstances. Junqueira and Schweigert^"^ found that sulfasuxidine inter- 

 fered with the conversion of tryptophan to nicotinic acid if folic acid was 

 not in the diet, but had no effect if the diet was supplemented with folic 

 acid. The significance, if any, of these reports in relation to the nicotinic 

 acid requirement of animals is not clear. 



(4) Age. Adult animals require less nicotinic acid than growing animals, 

 as might be expected.^- ^^' ^"^ 



(5) Climate. Mills and associates'^* found no difference in nicotinic acid 

 requirement between chicks kept at temperate coolness and at tropical heat. 



(6) Alcohol. Available evidence (p. 565) suggests that alcohol "spares" 

 nicotinic acid in man. However, in view of the high incidence of pellagra 

 in alcoholics, one might doubt the practical importance of this effect. 



B. MAN 



The recommended daily dietary allowance of nicotinic acid which is 

 generally applied in the United States is that of the Food and Nutrition 

 Board of the National Research Council '"^ According to this standard, the 

 daily diet of man should provide 12 to 18 mg. of nicotinic acid, depending 

 on activity, that for women 10 to 15 mg., depending on activity and whether 

 they are pregnant or lactating. Infants and children should receive from 4 

 to 17 mg. daily, depending on age up to 13 years, and on age and sex from 

 13 to 20 years of age. 



These allowances were based primarily on animal experiments and on 

 analyses of diets which were known to be pellagra preventive.'"^ They 

 contain a deliberate margin of safety to provide for those who may have 

 requirements above average or who by reason of illness or injury might 

 have a temporarily increased need for the vitamin. It should be emphasized 

 that the figures cited above are recommended allowances, not minimum 

 physiological requirements. 



1" W. R. Ruegamer, W. L. Brickson, N. J. Torbet, and C. A. Elvehjem, /. Nutrition 



36, 425 (1948). 

 lo^ L. J. Teply, W. A. Krehl, and C. A. Elvehjem, Avi. J. Physiol. 148, 91 (1947). 

 1" P. B. Junqueira and B. S. Schweigert, /. Biol. Chem. 175, 535 (1948). 

 i»4 R. Braude, S. K. Kon, and E. G. White, Biochem. J. 40, 843 (1947). 

 106 C. A. Mills, E. Cottingham, and E. Taylor, Am. J. Physiol. 149, 376 (1947). 

 1"^ Recommended Dietary Allowances, Bull. Natl. Research Council {U. S.) Reprint 



and Circ.Ser. 12Q, (1948). 



