804 XTII. ESSENTIAL FATTY ACIDS 



of the total plasma fatty acids consisted of dienoic, trienoic, and tetraenoic 

 acids, respectively. Hansen, Sinclair, and Wiese^^^ reported that no signifi- 

 cant differences in the values of the total plasma fatty acids were to he 

 noted in the case of fifty-seven poorly nourished infants and children, as 

 compared with the figures obtained for well-nourished subjects. However, 

 it was observed that the levels of dienoic, tetraenoic, and hexaenoic acids 

 were significantly lower in the poorly nourished individuals than in the 

 well-nourished group. There would thus appear to be a correlation between 

 the EFA content of the blood and the occurrence of eczema, not only in the 

 case of infants but also in that of young children and adults. 



In spite of the unequivocal relationship between the skin symptoms and 

 the blood level of EFA in man, it has not been possible to produce the fat- 

 deficiency syndrome in man experimentally by diet. In a single experi- 

 ment on a normal male subject maintained on a fat-free regimen for six 

 months, Brown et al}^^ were unable to observe any of the classical symptoms 

 of fat deficiency. It would have been surprising if any such symptoms had 

 appeared, since these conditions do not produce deficiency, even in rats. 

 How^ever, a 50% reduction in plasma linoleate and plasma arachidonate 

 occurred, which w^as completely out of proportion to the extent of decrease 

 of other blood lipids. In spite of this single negative result on man, it 

 would seem that the proof of the requirement of EFA by man is unequivocal. 

 Because of the greater life span, and the difficulties of experimenting with 

 humans, the fat-deficiency syndrome cannot be initiated as easily in man 

 as in the lower animals. Possibly man should be classified with the hog as 

 being less susceptible to fat deficiency, in contrast to the ready production 

 of the fat-deficiency syndrome in the mouse, rat, chicken, dog, and calf. 



{2) The Effect of Sex 



It is well known that a sex difference exists in the metabolism of fats. 

 This variation is reflected not only by the higher level of ketonuria which 

 obtains during fasting in w^omen, as compared with men, as demonstrated 

 by Deuel and Gulick,'^^ but also in the increased levels of urine ketone 

 bodies in the female rat in exogenous ketonuria, reported by Butts and 

 DeueP^® and in endogenous ketonuria by Deuel et al.,^^'' as compared with 



133 A. E. Hansen, J. G. Sinclair, and H. F. Wiese, /. Nutrition, 52, 541-554 (1954). 

 13* W. R. Brown, A. E. Hansen, G. O. Burr, and I. McQuarrie, ./. Nutrition, 16, 511- 

 524 (19.38). 



135 H. J. Deuel, Jr., and M. Gulick, /. Biol. Chem., 96, 25-34 (1932). 



136 J. S. Butts and H. J. Deuel, Jr., /. Biol. Chem., 100, 415-428 (1033). 



"■^ H. J. Deuel, Jr., L. F. Hallman, and S. Murray, ./. Biol. Chem., 11!), 257-268 (1937). 



