240 III. DIGESTIBILITY OF FATS 



of different quantities of crude fiber, rather than to divergences in the 

 capacity to absorb food fat. 



(9) Miscellaneous Factors 



Frazer 125 is of the opinion that the vitamins are not linked to the ab- 

 sorption of fat, although it had previously been suggested that fat ab- 

 sorption was influenced by deficiencies in vitamins A or B. Although, 

 in the sprue syndrome, a deficiency in fat absorption is sometimes associ- 

 ated with deficiencies in vitamins A, C, D, or E, these deficiencies are 

 slight and are probably due to difficulty in absorption. Butson 126 reported 

 that a 4000 Cal. high-fat diet containing 40.5% of fat is well tolerated at 

 0°F. but not at 32°F. Just why environmental temperature influences 

 fat digestibility is not understood. 



5. Pathologic Factors Altering the Digestibility of Fats 



Several abnormal conditions are recognized in man in which the digesti- 

 bility of fats is markedly lowered. Whenever a deficiency of pancreatic 

 lipase occurs in the intestine, due either to a failure of secretion of pancreatic 

 juice or to an obstruction of the pancreatic duct, the proportion of fecal 

 fat is considerably increased. This condition in which fatty stools occur 

 is usually referred to as steatorrhea. The defective fat absorption in the 

 case of pancreatic insufficiency is believed to result indirectly from the 

 failure of lipolysis. On the other hand, in another disease known as sprue, 

 the lipolysis of fat proceeds normally, but the failure in absorption repre- 

 sents an interference in the pathway of absorption through the intestinal 

 wall. Although the etiology of some types of steatorrhea is known, the 

 cause of sprue and of congenital steatorrhea remains somewhat obscure. 

 In 1921, Schmidt and von Noorden 127 produced an excellent monograph 

 dealing with intestinal absorption in disease, while French, 128 in 1952, 

 surveyed the status of our knowledge concerning defective fat absorption. 



(1) Methods for the Recognition of Defective Fat Absorption 



a. By Chemical Estimation of Fecal Fat. According to French, 128 it has 

 been the general practice, during the past fifty years, to base the diagnosis 



» A. C. Frazer, Bull. soc. chim. biol, S3, 968-972 (1951). 



126 A. R. C. Butson, Lancet, 258, 993-994 (1950). 



127 A. Schmidt and C. von Noorden, Klinik der Darmkrankheiten, Vol. 5, 2nd ed., 

 Bergmann, Munich and Wiesbaden, 1921. 



128 J. M. French, "Defective Fat Absorption in Man," in R. T. Williams, Lipid Metah 

 olism, Biochem. Soc. Symposia, No. 9, Cambridge Univ. Press, 30-3G (1952). 



