220 III. DIGESTIBILITY OF FATS 



Deuel 62 on rats, as to whether or not lower coefficients of digestibility 

 would have been obtained in the tests on human subjects had the soap 

 fraction been included in the calculation. In the latter tests with rats, 

 the digestibility of hydrogenated lard melting at 55°C. was 63.2, while 

 that of the lard melting at 61 °C. was found to be 21.0. If no allowance 

 had been made in the calculations for the soap fraction, the figures for 

 digestibility would have been 100 and 91, respectively. In the light of 

 these studies on rats, further tests on human subjects are obviously needed 

 to determine whether or not a similar phenomenon applies to man. 



c. Digestibility of Oleomargarines. All evidence points to the conclu- 

 sion that oleomargarines are as completely utilized as are the natural fats 

 melting below 50° C. This high digestibility was recorded by Holmes 67 

 for the margarines containing mixtures of animal and vegetable fats, in 

 current use during the period from 1910 to 1920, as well as for a sample 

 prepared by modern technics using hydrogenated vegetable oils. 68 These 

 data are summarized in Table 12. 



Table 12 

 Average Coefficients of Digestibility of Some Oleomargarines in Human 



Subjects 



Av. Coeff. 



Number fat of 



Composition expts. eaten, g. digestibility 



59% Oleo oil, 7% lard, 22% vegetable oils 



(cottonseed, peanut), 12% milk fat° 9 97.2 



41% Oleo oil, 32% lard, 24% vegetable oil 



(peanut), 3% milk fat" 7 80 93.4 



67% Oleo oil, 33% vegetable oil (cottonseed), 



0.1% milk fat" 4 — 96.8 



Vegetable oil margarine (m.p., 94-95 °F. 



(Wiley))* 7 86.5 96.7 



" A. D. Holmes, Boston Med. Surg. J., 192, 1210-1212 (1925). 

 b H. J. Deuel, Jr., J. Nutrition, 32, 69-72 (1946). 



Although the experiments on man were carried out without considera- 

 tion of the soap fraction excreted in the feces, there is no reason to ques- 

 tion the high digestibility of oleomargarine. In these experiments, there 

 was no indication of a large bulk of feces which would normally accom- 

 pany any considerable excretion of soap. Moreover, there are consider- 

 able data in the literature indicating the practically complete digestibility 

 of margarine in other species. For example, confirmatory tests by Crockett 

 and Deuel, 62 with rats, demonstrated that the average coefficient of 



87 A. D. Holmes, Boston Med. Surg. J., 192, 1210-1212 (1925). 

 • 8 H. J. Deuel, Jr., J. Nutrition, 32, 69-72 (1946). 



