CONTENTS XXXV 



XIV. The Nutritional Value of Fats (continued) 



(12) Fatty Acids as Required Growth Factors for Bacteria 887 



a. Oleic Acid as a Substitute for Biotin 887 



b. Comparative Potencies of Octadecenoic Acids . 890 



c. Comparative Potency of Other Unsaturated Acids and of 



Related Compounds 891 



d. The Effect of Saturated Acids upon Bacterial Growth 892 



e. Growth Stinuilation of Bacteria Produced by Mixed Fatty 



Acids from Various Natural and Artificial Fats 893 



f. Effects Other Than the Biotin-like Effect of Unsaturated 



Fatty Acids on Growth of Bacteria 893 



(13) Fatty Acids as Growth Factors for Lower Organisms, 896 



(14) Miscellaneous Beneficial and Harmful Effects of Fats 896 



3. Factors Altering the Nutritional Value of Fats and Oils 898 



( 1 ) Comparison of the Nutritional Value of Fats and Oils Based upon 



Composition 898 



a. Fat-Soluble Vitamin Content 898 



(a) Vitamins A and Carotene 898 



(b) Vitamins D 900 



(c) Tocopherols (Vitamins E) 903 



b. Resume of the Effect of Composition on the Nutritional Value 



of Fats and Oils 904 



(2) Comparison of the Nutritional Value of Fats and Oils, Based upon 



Physiologic Response 904 



a. Introduction 904 



b. The Digestibility of Fats and Oils 905 



(a) The Digestibility of Vegetable and of Animal Fats in Man 905 



(b) Resume of the Comparative Digestibility of Fats and Oils 906 



c. The Effect of Absorption on the Nutritional Value of Fats .... 906 



(a) Absor]3tion Rates of Different Fats 907 



(b) Resume of the Comparative Absorption Rates of Fats and 



Oils 908 



d. The Nutritional Value of Animal vs. Vegetable Fats 909 



(a) Relative Nutritional Value Based upon Growth Tests. . . . 909 



a'. Experiments on Normal Rats 909 



b'. Experiments on Premature!}' Weaned Rats 912 



c'. Experiments on Rats Subjected to Undernutrition. . . 913 



d'. Experiments on Rats Receiving Growth Hormone. . . . 913 



e'. Experiments on Calves 914 



f. E.xperiments on Children 915 



g'. The Relationship of the Vaccenic Acid Content to the 



Alleged Superior Growth-Promoting Activity of 



Butter 915 



(b) Relative Nutritional \'alue as Based uj)on Pregnancy and 



Lactation Tests 916 



(c) Multigene ration Tests as a Method for Comjjaring the 



Nutritional Value of Animal and of Vegetable Fats 918 



