336 ASCORBIC ACID 



fecal excretion of the vitamin, probably owing to failure in al3Sorption.'*^^ 

 Before drawing conclusions, however, as to the presence of ascorbic acid 

 in the feces, tests should be conducted to eliminate reductone and reductic 

 acid as possible interfering substances/^^- '*^^ Losses in sweat are negligible 

 unless sweating is very profuse or the intake of the vitamin low.''^^'*'* 



The ability of the tissues to retain ascorbic acid depends somewhat on 

 factors other than the degree of saturation of the tissues of the l)ody. In- 

 cluded among these other factors are: (a) intake of acids and alkalies, (b) 

 nature of the diet, (c) the vitamin as it occurs in foods as compared to the 

 synthetic product, (d) effects of fever, (e) trauma, and (f) exercise. 



a. Intake of Acids and Alkalies 



Hawley et al}^^ made a study of the effect of pH changes of the urine 

 resulting from ingestion of sodium bicarbonate and ammonium chloride in 

 relation to urinary excretion of the vitamin in human subjects. They found 

 a marked decrease in output when the urinary pH was in the alkaline range 

 7.5 to 8.1. The plasma ascorbic acid level was lowered by ingestion of either 

 sodium bicarbonate or ammonium chloride. The lowered excretion of the 

 vitamin which occurs after ingestion of sodium bicarbonate is probably a 

 result of increased destruction during the excretion process, and the in- 

 creased excretion of the vitamin after ammonium chloride ingestion may 

 be a result of increased preservation during the excretory process. Haw- 

 thorne and Storvick^-" made a study with similar results indicating an 

 interference with normal utilization. 



h. Nature of the Diet 



Little is known about this factor. Patterson and Bourqum^-^ reported less 

 than a 2 % difference in ascorbic acid excretion in six of eight women sub- 

 jects on a balanced diet high in protein as compared to the excretion on a 

 normal diet. The amount of the vitamin necessary for saturation was 

 slightly greater for the high protein diet. Similar studies on the effect of 



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(1940). 

 <»* M. Miller, Food Research 12, 343 (1947). 

 «6 E. M. Hewston, M. Fisher, and E. Orent-Keiles, U. S. Dept. Agr. Tech. Bull. 1023 



(1951). 

 "« D. M. Tennent and R. H. Silber, J. Biol. Chem. 148, 359 (1943). 

 ^'^ O. Mickelsen and A. Keys, J. Biol. Chem. 149, 479 (1943). 

 ^'8 J. B. Shields, B. C. Johnson, T. S. Hamilton, and H. H. Mitchell, J. Biol. Chem. 



161, 351 (1945). 

 *i3 E. E. Hawley, R. G. Saags, and D. J. Stephens, /. Nutrition 14, 1 (1937). 

 «» B. E. Hawthorne and C. A. Storvick, Proc. Soc. Exptl. Biol. Med. 67, 447 (1948). 

 "' I. Patterson and A. Bourquin, Am. J. Digest. Diseases 10, 390 (1943). 



