XI. IIEQUIREMENTS 387 



d. Age 



Dann ami C'owgill^" reported that age is not a factor in determining the 

 vitamin C retjuirement of <»;uinea pigs. An intake of 0.5 mg. per 100 g. of 

 body weight ga\'e full protection to animals of various ages and weights. 

 A more efficient utilization of the vitamin by rapidly growing guinea pigs 

 has been suggested as the explanation for their not having a greater re- 

 quirement in relation to body weight than adult animals.*' However, 

 Pfander and Mitchell* obtained results which suggest a slightly higher 

 requirement in younger animals. 



e. Type of Diet 



There is little exact information concerning effects of variations in the 

 basal dietary constituents on the ascorbic acid requirement. With diets 

 high in tyrosine content, presumably there would be a somewhat elevated 

 need of the \'itamin. In animals which sj^nthesize ascorbic acid, the addi- 

 tion to the diet of compounds such as methionine and chloretone which 

 have a stimulating effect on its synthesis may be important. The lack of 

 such substances in synthetic diets may be one reason why their growth- 

 promoting ability is less than that of diets composed of natural material, 

 although they contain the same amounts of proteins, carbohydrates, fats, 

 vitamins, and minerals as the synthetic diets. 



/. Special Factors Such as Flavonoids 



Studies have been made of the effects of substances such as rutin on the 

 vitamin C requirements. A sparing action on ascorbic acid has been re- 

 ported." Other studies have also been made in this field. *^' *^ There is no 

 clear e\adence that the guinea pig requires flavonoids in the diet when ample 

 ascorbic acid is present. 



g. Infections 



The presence of infection may influence the ascorbic acid requirement 

 in tw^o ways. (1) IMore of the vitamin tends to be consumed as a result of 

 increased leucocytosis^* and possibly of fever ;"-^* hence the antiscorbutic 



"M. Dann and G. R. Cowgill, J. Nutrition 9, 507 (1935). 



" M. E. Reid, J. Nutrition 42, 347 (1950). 



" E. W. Crampton and L. E. Lloyd, J. Nutrition 41, 487 (1950). 



" H. Cotereau, M. Gabe, E. G(5ro, and J. L. Parrot, Nature 161, 557 (1948). 



" A. M. Ambrose and F. DeEds, J. Nxdrition 38, 305 (1949). 



'* F. X. Hausberger and X. Xevenschwander-Lemmer, Klin. Wochschr. 18, 1119 



(1939). 

 " I. L. Stutskii, Klin. Med. (U. S. S. R.) 16, 1084 (1937); C/jm. Zentr. 1, 4680 (1938). 

 " G. Marotta and G. Calendoli, Boll. sac. ital. biol. sper. 19, 16 (1944). 

 58 F. H. Heise and G. J. Martin, Proc. Soc. Exptl. Biol. Med. 34, 642 (1936). 

 "G. Scoz, Boll. soc. ital. biol. sper. 11, 908 (1936). 



