922 XIV. NUTRITIONAL VALUE OF FATS 



rancid fat in the diet increases the protein requirement of the rat for optimal 

 growth. However, a diet containing 10% of rancid soybean oil supported 

 almost normal growth in rats when all essential nutrients were supplied in 

 large amounts and protein constituted 30% of the diet. Under these 

 conditions the only organ weight seriously affected by the presence of rancid 

 fat was that of the intestinal tract. Greenberg and Frazer^^^ also showed 

 that whole desiccated liver benefited the rats in proportion to the protein 

 content, but that cortisone exerted no beneficial effect. Drugs given to 

 change the intestinal flora did not modify the growth of rats fed rancid fat. 



Kaunitz^^^ found that the feeding of highly oxidized fats was not as toxic 

 as is generally believed, if additional protein was added to the diet. This 

 worker considers that the protein reduces the active compounds of oxidized 

 fat and thus inactivates them. The effect may possibly be due to relatively 

 easily reduced products which are formed during oxidation. 



Burr and Barnes^^^ reviewed the subject up to 1943. According to these 

 authors, the following substances might be destroyed by the prooxidant 

 effect of the fats: vitamin A, carotene, vitamin D, vitamin E, pantothenic 

 acid, pyridoxine, biotin, ascorbic acid, and linoleic acid. Although the 

 information is not complete on the effect of oxidized fat on all of these sub- 

 stances, considerable experimental data have been amassed. It is sug- 

 gested that the dermatitis which sometimes occurs in older animals, and 

 the caudal necrosis in the newborn which have been subjected to diets defi- 

 cient in vitamin E, are relieved by the administration of wheat germ oW.^^ 

 Although the effect of rancid fats on pantothenic acid or on pyridoxine is 

 not known, it has been shown that biotin, at least, is destroyed by organic 

 peroxides, ^^''•^^^ and by products formed in rancid fats.^^® Fritz and co- 

 workers^^^ demonstrated that rancid fats are also of importance in the 

 destruction of vitamin D, due to the oxidation which occurs. Ascorbic 

 acid, which is known to act as an antioxidant, is not appreciaV)ly oxidized 

 during the induction period of rancidity. ^^"^ 



When peroxidation of unsaturated fats occurs, linoleic acid is destroyed. 

 Feeding of these fats has been shown to result in fat-deficiency symptoms 

 in rats"^ and in skin lesions in dogs.^^^ These skin lesions suggest linoleic 



3«5 H. Kaunitz, Arch, exptl. Pathol. PhnrmakoL, 220, 16-25 (1953). 

 3«6 G. O. Burr and R. H. Barnes, Physiol. Revs., 23, 256-278 (1943). 

 »«' H. A. Mattill and C. Golumbic, J. Nutrition, 23, 625-631 (1942). 

 5«8 G. B. Brown and V. du Vigneaud, /. Biol. Chem., Ul, 85-89 (1941). 

 369 J. C. Fritz, J. L. Halpin, and E. H. Kramke, Ind. Eng. Chem., 34, 979-982 (1942). 

 "» C. Golumbic and H. A. Mattill, J. Am. Chem. Soc, 63, 1279-1280 (1941 ). 

 3" D. V. Whipple, Oil & Soap, 10, 228-229 (1933); Am. J. Med. Set., 187, 864-865 

 (1934). 



*'2 D. V. Whipple, Proc. Soc. Exptl. Biol. Med., 30, 319-321 (1932). 



