NORMAL FACTORS ALTERING DIGESTIBILITY OF FATS 235 



(7) The Effeci of Emulsifying Agents 



The extent of digestibility of fats has been shown to be improved when 

 emulsifying agents are present. Although it is impossible to improve 

 the digestibility of highly digested fats by the use of emulsifying agents, 

 Augur and co-workers 39 were able to show a marked elevation in the co- 

 efficients of digestibility of hydrogenated cottonseed oils when lecithin 

 was added to the diets. The coefficients of digestibility without and with 

 lecithin were as follows: sample melting at 46°C, 83.8 and 87.9; sample 

 melting at 54°C, 68.7 and 82.8; and the sample melting at 65°C, 24.0 

 and 44.2. 



"Tween 80" (PSM or polyoxyethylene-sorbitan monooleate) is an 

 especially effective emulsifying agent. When this was added to the diet 

 of patients having a poor fat digestibility, Jones el al. no were able to 

 demonstrate a marked increase in the coefficients of digestibility of fat. 

 Tween 20 (polyoxyethylene sorbitan monolaurate) was found by Johnson 

 et al. nl also to increase the fat retention to some extent in the case of pre- 

 mature infants. Thus, in over 50% of the cases tested, the administra- 

 tion of this drug slightly increased the coefficient of digestibility of fat. 

 The effect of lecithin and PSM on the rate of fat absorption has been 

 described earlier (page 185). 



(8) The Effect of Foodstuffs Concomitantly Present with Ingested Fat 



There are a number of ways in which the digestibility of fat may be 

 influenced by other materials present in the stomach and intestines. The 

 most important substances, which may produce a decrease in fat absorp- 

 tion, are the salts which form insoluble soaps with the fatty acids, and 

 hence may prevent the absorption of a large proportion of these acids. 

 The length of stay in the intestine may be so reduced, when intestinal 

 irritants are present, as to prevent the complete utilization of the fat. 

 The accompanying foodstuff may change the conditions in the intestine 

 by altering the pH, increasing the flow of bile, pancreatic juice, or in- 

 testinal juice, or by a variety of other changes. 



a. The Effect of Calcium and Magnesium Salts. Although Cheng and 

 her associates 5 reported that no appreciable effect was exerted on the high 

 digestibility of bland lard when calcium salts were present in the diet, the 



110 C. M. Jones, P. J. Culver, G. D. Drummey, and A. E. Ryan, Ann. Internal Med., 

 29, 1-10 (1948). 



111 A. L. Johnson, R. B. Scott, and L. H. Newman, Am. J. Diseases Children, 80, 

 545-550 (1950). 



