DIGESTION, ETC. OF FAT-SOLUBLE VITAMINS 317 



after equal doses of vitamin A esters than after the vitamin A alcohol. 

 In both sets of experiments, the increased vitamin A in the blood serum 

 was composed of the ester, irrespective of the form in which the vitamin 

 A preparation was given. 



g'. The Effect of Emulsifying Agents: Lecithin has been shown to 

 enhance the absorption of vitamin A. Thus, Esh and Sutton 241 and 

 Scharf 434 noted that vitamin A is better utilized when given with soybean 

 lecithin than when this phospholipid is absent. Esh and co-workers 435 

 reported that a similar phenomenon obtains in dairy cattle. The trans- 

 mission of dietary vitamin A to colostrum was increased by feeding leci- 

 thin; the liver storage of vitamin A was also augmented when lecithin 

 was included in the diet. Moreover, the ability of vitamin A to depress 

 the carotene level was increased. In the case of man, Adlersberg rt al. i36 

 reported that lecithin promotes the absorption of vitamin A in sprue but 

 not in liver disease. 



h'. The Utilization of Vitamin A in Aqueous Dispersion: Several 

 groups of workers 415 - 427,437-450 have found that vitamin A in aqueous dis- 

 persion is more effective than when given in an oil solution. The experi- 

 mental procedures followed in differentiating between the absorption of 



434 A. Scharf, Food Materials and Equip., 7, 8-9 (1947); cited bv P. L. Harris, Ann. Rev. 

 Biochem., 18, 391-4.34 (1949), p. 399. 



436 G. C. Esh, T. S. Sutton, J. W. Hibbs, and W. E. Krauss. J. Dairy Sri., 31, 461-478 

 (1948). 



436 D. Adlersberg, S. Kann, A. P. Maurer, K. Newerly, W. Winternitz, and H. Sobotka, 

 Gastroenterology. 10, 822-830 (1948). 



437 B. Kramer, A. E. Sobel, and S. P. Gottfried, Am. J. Diseases Children, 73, 543-553 

 (1947). 



438 J. M. Lewis, O. Bodanskv, J. Birmingham, and S. Q. Cohlan, J. Pcdiat. 31, 496- 

 508(1947). 



439 C. D. May and C. U. Lowe, J. Clin. Inrrst., 27, 226-230 (1948). 



410 A. E. Sobel, L. Besman, and B. Kramer, Federation Proc, 7, 189-190 (1948). 



441 A. E. Sobel, A. A. Rosenberg, and B. Kramer, Abst. 114th meeling, Am. Chem. Soc, 

 Div. Biol. Chem., Aug. 30, 1948. 15C-16C. 



442 A. E. Sobel and A. A. Rosenberg, ./. Nutrition, 42, 557-563 (1950). 



443 A. E. Sobel, A. A. Rosenberg, R. Geduldig, E. Engel, M. West, and B. Kramer, 

 Federation Proc., S. 253-254 (1949). 



444 H. Popper, F„ Steigmann, and H. A. Dvniewicz, Gastroenterology, 10, 987-1000 

 (1948). 



446 C. J. Kern and T. Antoshkiw, Ind. Eng. Chem, 42, 709-713 (1950). 



446 A. E. Sobel, M. Sherman, J. Lichtblau, S. Snow, and B. Kramer, J. Nutrition, 35, 

 225-238(1948). 



447 H. Popper and B. W. Volk, Proc. Soc. Exptl. Biol. Med., 68, 562-564 (1948). 



448 G. R. Halpern. J. Biely, and F. Hardy, Science, 106, 40-41 (1947). 



449 G. R. Halpern and J. Biely, ./. Biol. Chem., 174, 817-826 (1948). 



450 B. C. Barnes, E. E. Wollaeger, and H. L. Mason. ./. Clin. Invest., 29, 982-987 

 (1950). 



