344 IV. DIGESTION OF LIPIDS OTHER THAN FATS 



Under abnormal conditions in the gastrointestinal tract, such as sprue 

 and other related steatorrheas, fat utilization may be greatly impaired, 

 as has already been reported (see Chapter III). Heerschma and An- 

 negers 609 demonstrated this phenomenon as a result of diversion of bile 

 from the gastrointestinal tract in dogs. Thus, while the total fat and fatty 

 acids excreted in the feces of normal dogs remained constant and inde- 

 pendent of fat or fiber intake, in the case of bile fistula dogs, the fecal fat 

 increased linearly as dietary fat was increased. It was calculated that 

 the fecal fat under such conditions could be predicted from the sum of the 

 constant amount present on the fat-free diet and 58% of the dietary fat. 

 Moreover, the ratio of free fatty acids to total fecal fat was significantly 

 higher in bile fistula dogs than in normal animals. The fecal fat in bile 

 fistula dogs receiving 15 to 40 g. of triglyceride daily was not altered by 

 the inclusion of 2 to 4 g. of Tween 80 in the diet. 610 



Components of the diet other than lipids may likewise alter the excre- 

 tion of fecal lipids. Thus, Schulz and Thomas 611 reported that, on a 

 basal diet containing sucrose and 10% soybean oil, the addition of cystine, 

 methionine, vitamin C, bile salts, sodium fluoride, carotene, calcium car- 

 bonate, calcium chloride or calcium lactate had no effect upon the per- 

 centage of fecal excretion of lipids, or upon the retention of the lipids. 

 However, the inclusion of 20% of charred alfalfa or 10% of agar-agar, as 

 well as the substitution of lactose for sucrose, resulted in an increase in 

 fecal lipids. When starch replaced the sucrose, the addition of carotene 

 to the diet resulted in a significant increase in fecal lipids. Walker 612 

 suggests that the increased lipid secretion in the intestine brought about 

 by the inclusion of fiber in the diet is due to the stimulating effect of the 

 mechanical action of the fiber itself on the intestinal mucosa. This secre- 

 tion would then act as a conditioning or lubricating agent for the intestine. 



12. The Composition of Fecal Lipids 



As early as 1813, Home 613 recognized that fatty materials arc present 

 in feces. In 1884, Miiller 614 concluded that, since fats are present in the 

 meconium as well as in the feces of the adult during fasting, they must 

 represent excretion products. 



609 J. R. Heerschma and J. H. Annegers, Am. J. Physiol, 158, 143-147 (1953). 



610 J. H. Annegers, Proc. Soc. Exptl. Biol. Med,, 81, 277-278 (1952). 



611 J. A. Schulz and B. H. Thomas, J. Nutrition, 48, 175-187 (1952). 

 812 A. R. P. Walker, Nature, 164, 825-827 (1949). 



413 E. Home. Phil. Trans., Roy Soc. {London), 103, 146-158 (1813). 

 •»* F. Midler, Z. Biol, 20, 327-377 (1884). 



