882 XIV. NUTRITIONAL VALUE OF FATS 



somewhat later Bireh'^^ proved that the addition of fat to the diet delayed 

 the onset of dermatitis produced by pyridoxine deficiency. In some cases 

 it completely prevented the development of this abnormal skin condition. 

 Salmon'^^ also demonstrated that pyridoxine and the fat supplement each 

 other in curing dermatitis. 



The bulk of the evidence indicates that the effectiveness of the fat in 

 curing dermatitis is directly proportional to the degree of its unsaturation 

 and thus presumably to the essential fatty acid content. The latter ex- 

 planation might readily account for the fact that lard, which ordinarily 

 has a very high essential fatty acid content, "will be effective in alleviating 

 pyridoxine deficiency, whereas butter, which has a relatively low essential 

 fatty acid content, is somewhat less efficacious in this respect. According 

 to Schneider^"" the low antidermatitis potency of rancid butter is attrib- 

 utable to the fact that the antidermatitis factor has been destroyed by 

 the oxidation. 



Kummerow and collaborators-"^ reported that small quantities of oxi- 

 dized fats cure acrodynia in rats; rancid methyl linoleate was less effective 

 than was the freshly-distilled ester. Tocopherol did not improve the 

 effectiveness of rancid ethyl linoleate, while ethanolamine aggravated the 

 s^miptoms. Drastically oxidized fats, and 10,r2-ethvl linoleate, Avere 

 ineffectiA'e as curative agents. It is indicated that the various supple- 

 ments of oxidized linoleate esters were converted to oleic acid and to sat- 

 urated fatty acids. 



All of the commonly occurring essential fatty acids are effective in 

 alleviating pyridoxine deficiency. Quackenbush et al}^'^ reported that, of 

 these several essential fatty acids, ethyl linoleate is the most effective, 

 especially when given in conjunction with pyridoxine. Linolenic and 

 arachidonic acids were somewhat less satisfactory in alleviating the der- 

 matitis. Schneider and co-workers-"^ agree that linoleic acid possesses 

 the greatest potency. They call attention to the fact that the effectiveness 

 of several natural fats in clearing up acrodynia is in proportion to their 

 linoleate content. Thus corn oil was shown to have a greater activity than 

 did linseed oil. "While other fats exerted a curative effect proportional to 

 their linoleate content, cod liver oil was completely ineffective. ^^^ Ac- 



198 T. W. Birch, J. Biol. Chem., 124, 775-793 (1938). 



199 W. D. Salmon, /. Biol. Chem., 123, civ-cv (1938). 



200 H. A. Schneider, Proc. Soc. Exptl. Biol. Med., 44, 266-267 (1940). 



201 F. A. Kummerow, T. K. Chu, and P. Randolph, J. Nutrition, 36, 523-536 (1948). 



202 F. W. Quackenbush, H. Steenbock, F. A. Kummerow, and B. R. Platz, ./. Nutrition, 

 ^4,225-234(1942). 



203 H. A. Schneider, H. Steenbock, and B. R. Platz, /. Biol. Chem., 132, 539-551 

 (1940). 



