908 XIV. NUTRITIONAL VALUE OF FATS 



and Hallmaii'^* reported that the most rapid absorption occurred with 

 triacetin and tributyrin, while it was somewhat slower in the case of tri- 

 caproin and tricaprylin. As soon as the short-chain triglycerides in the 

 butterfat are absorbed, the rest of the butter triglycerides are utilized at a 

 rate comparable with that of other fats. 



Among the fats liquid at ordinary temperatures, rapeseed oil offers an 

 interesting result. Although the figures for absorption during the first 

 three-hour period are only slightly less than those of other fats, the figure 

 for the second three-hour period are definitely low.'^^* In this case the low 

 absorption can be correlated \\ith a low reported digestibility in rats,-'^ but 

 not in man."^'^ High-melting fats, also, are slowly absorbed. Hydrogenated 

 cottonseed oil melting at 46°C. and 54°C., and hydrogenated lard melting 

 at 55 °C., are absorbed more slowly than are other natural fats. This effect 

 can like^^^se be correlated with the low digestibilities of these products. ^^^-^^^ 



(6) Resume of the Comparative Absorption Rates of Fats and Oils. There 

 is no valid evidence as to whether fat should preferably be absorbed rapidly 

 or slowly. When fatty foodstuffs are absorbed quickly, they can be toler- 

 ated in larger amounts than otherwise, and they furnish body energy more 

 promptly than in the case of samples which are absorbed more slowly. 

 Conversely, when the materials are absorbed slowly they prevent hunger 

 over a longer period, and cause the feeling of satiety for a prolonged inter- 

 val of time, thus reducing the caloric intake. In the latter case, the increase 

 of blood lipids associated with absorption is less marked when absorption 

 proceeds over a long period, and this might be expected to tax the body to 

 a lesser extent. Howe"\'er, if absorption is so slow that it is not completed 

 before the fat leaves the small intestine, the slow absorption rate may be 

 considered to be a factory contributing to a lower nutritional value, inas- 

 much as the coefficient of digestibility of the fat would therefore be reduced. 



In summarizing the limited data which are available, one is impressed 

 with the fact that most of the natural fats and oils are absorbed at quite 

 similar rates. During the early period of absorption, butter seems to be 

 more rapidly absorbed; on the other hand, during the later periods the 

 rate of absorption of butter agrees quite closely with that of other natural 

 fats. Rapeseed oil is absoi'bed ^'ery rapidly after the first preliminary 

 period of absoi'ption. Hydrogenated fats such as margarines, lard, and 



2" H. J. Deuel, Jr., and L. Hallman, ./. Nutrition, 20, 227-232 (1940). 

 "5 H. J. Deuel, Jr., L. Hallman, and A. Leonard, J. Nutrition, 20, 215-226 (1940). 

 296 H. J. Deuel, Jr., A. L. S. Cheng, and M. G. Morehouse, /. Nutrition, 35, 295-300 

 (1948). 



"7 M. E. Crockett and H. J. Deuel, Jr., /. Nutrition, 33, 187-194 (1947). 



298 V. Augur, H. S. RoUman, and H. J. Deuel, Jr., J. Nutrition, S3, 177-180 (1947). 



