318 IV. DIGESTION OF LIPIDS OTHER THAN FATS 



the aqueous suspensions and of the oil solutions were not exactly com- 

 parable, inasmuch as, in the first case, vitamin A alcohol is generally em- 

 ployed, while in the second instance vitamin A ester is used. However, 

 Kagan et al. 4bl are of the opinion that this difference in utilization is to be 

 traced to the physical state of the vitamin rather than to the alcohol as 

 opposed to the ester. On the other hand, Popper and Volk 447 ascribe 

 the differences to the passage of increased amounts of vitamin A through 

 the epithelium if given in aqueous dispersion and not to a difference in 

 the physical state of the vitamin A after its passage into the cell. Kagan 

 and associates 451 also demonstrated that the increase in plasma vitamin A 

 was similar when aqueous suspensions of vitamin A alcohol and of vitamin 

 A palmitate, respectively, were given. Sobel et al. 4U reported that the 

 decrease in the rate of absorption of vitamin A observed in the newborn 

 when the vitamin is administered in oil is overcome when an aqueous dis- 

 persion containing 16% of polyoxyethylene sorbitan monolaurate (Tween 

 20) is employed. Enhanced absorption of vitamin A has been noted 

 in normal men and in individuals whose utilization of fat is impaired. 

 Thus, Barnes and co-workers 450 reported that normal subjects had higher 

 plasma curves and lower fecal losses of vitamin A after the ingestion of 

 the aqueous dispersion than after taking an oil solution of vitamin A. 

 Although the patients with non-tropical sprue had flat plasma curves and 

 excessive fecal losses with both preparations, the results with the aqueous 

 preparation were superior to those with the oil solution. The vitamin A 

 plasma curve was also restored to normal in a patient with diabetes mel- 

 litus and steatorrhea after the ingestion of the aqueous dispersion, al- 

 though the losses in the feces remained high. 



Krantz 452 also reported an improvement in the vitamin A utilization 

 in both normal controls and diseased patients when an aqueous dispersion 

 of vitamin A was used. Thus, when 200,000 I.U. of vitamin A ester were 

 given to normal men alone or with 2 g. of Tween 80 (PSM), the speed 

 at which the maximum blood level was reached was found to be quite 

 different. 452 The peak value, when the vitamin A ester was given alone, 

 was reached at five hours while, in the presence of PSM, the blood vitamin 

 A attained the maximum level in only three hours. This would suggest 

 that absorption is more rapid when PSM is present. Another striking 

 example of improved absorption of vitamin A resulting from the use of 

 aqueous solutions stabilized with PSM was in the case of patients suffer- 

 ing from such conditions as subtotal gastrectomy, sprue, pancreatic fibro- 



161 B. M. Kagan, D. A. Jordan, and D. S. Gerald, ./. Nutrition, 40, 275-279 (1950). 

 452 J. C. Krantz, Unpublished observations cited in Nutrition Revs., 7, 205-207 (1949). 



