UNITED STATES DEPARTMENT OF AGRICULTURE 



1 BULLETIN No. 310 ( 



'm^Sx IS 



Contribution from the States Relations Service % 



A. C. TRUE, Director J&&"^?£fU 



Washington, D. C. PROFESSIONAL PAPER November 9, 1915 



DIGESTIBILITY OF SOME ANIMAL FATS. 



By C. F. Langworthy, Chief, and A. D. Holmes, Scientific Assistant, Office of Home 



Economics. 



CONTENTS. 



Introduction 1 



Nature of the diet 2 



Experimental methods 4 



Digestion experiments — Lard, beef fat, mut- 

 ton fat, butter 5 



General discussion 20 



INTRODUCTION. 



Notwithstanding the fact that fats are ordinarily one of the prin- 

 cipal sources of energy in the diet and are two and one-fourth times 

 as effective for this purpose as either protein or carbohydrates, their 

 use in the diet has received less attention by investigators, and is 

 consequently less perfectly understood than that of other nutrients. 



It has generally been taken for granted that when eaten in favorable 

 combinations fats are thoroughly assimilated and that the different 

 kinds do not vary enough in this respect to affect materially the 

 amount of energy which the body derives from them. The recorded 

 experimental data, however, are not conclusive on this point. Ex- 

 perimental data are also very limited on another point which is a 

 matter of particular interest at the present time, when the increased 

 demand for culinary and table fats tends to bring into the market 

 kinds which have hitherto been used little if at all, namely, the rela- 

 tion of melting point to thoroughness of digestion, particularly with 

 respect to fats of high melting point. 



It is true that many digestion experiments have been carried on 

 with food materiaLs such as milk, cheese, meat, etc., which contain 

 much fat, but relatively few dealing directly with culinary and table 

 fats have been reported and only a small proportion of these have been 

 made under comparable conditions, and while it is also true that the 

 melting point of fats has been very generally and accurately deter- 



N'ote.— This bulletin records studies of the (llj/'stibllity and melting point of lard, beef fat, mutton fat, 

 and butter, and is primarily of Interest to students and Investigators of food problems. 

 -Bull. ."ilfJ — 15 1 



