866 XIV. NUTRITIONAL VALUE OF FATS 



pecially fatty acids, inhibit the growth of certain bacteria, especially tliat 

 of the tubercle bacillus. Thus, Hedgecock^^^ showed that the administra- 

 tion of a non -lipid, casein-supplemented ration to resistant albino mice 

 retarded the progress of experimental mouse tuberculosis. The condi- 

 tion was also retarded when 20% of the total fatty acids of coconut oil 

 were added to the dietary mixture. On the other hand, olive oil, linseed 

 oil, and oleic acid appeared to aggravate the experimental tuberculosis 

 when these compounds were added to the ration to the extent of 20%. 

 Hanel and Filler' ^^ reported that dietary fats in general tend to alleviate 

 tuberculosis in man. HoAvever, cod liver oil apparently has a superior 

 therapeutic action. It is suggested that the unsaturated fatty acids in 

 cod liver oil account for this favorable action upon tuberculosis, as it was 

 demonstrated that these acids, diluted 1 to 50,000, will retard the gro\vth 

 of tubercle bacilli in vitro. On the other hand, Miura"® reported, on the 

 basis of examination of the action of sixty-four fatty acid derivatives 

 against Mycohacterium avium that the most effective derivative was a- 

 ethylmyristic acid; a-phenylmyristic acid was effective only in vitro, and 

 had no therapeutic value in mice. Among the alkyl fatty acids having 

 eight to eighteen carbon atoms, the 0x4 acid (myristic), had the greatest 

 antibacterial action. In the Cig series, the unsaturated acids were found 

 to be more effective than the saturated forms. Of the unsaturated acids, 

 the cis forms are more active than are the tra7is isomers. Free acids have 

 greater activity than do the esters. Of the branched-chain acids, those 

 with the ethyl group are the most potent.^'® Dubos"^ reported that the 

 short-chain aliphatic acids such as acetic, propionic, butyric, caproic, ca- 

 pryUc, and capric acids exerted a marked bacteriostatic effect upon mam- 

 malian tubercle bacilli in vitro. Lactic acid in low concentrations also 

 inhibited groAAth. However, keto and dicarboxylic acids exhibited no 

 inhibitory action. More recently (1952) WeitzeP'^ reported that there 

 was no relation between the tuberculobacteriostatic action of the total 

 fatty acids and their iodine values. The most pronounced antibacterial 

 action was found in the case of the pure Cis acids with two double bonds, 

 especially when the bonds were conjugated. Acids with three double 

 bonds, however, did not exert any stronger antibacterial action than did 

 those with two double bonds. 



"^ L. W. Hedgecock, Proc. Soc. Expfl. Biol. Med., 68, 106-110 (1948). 

 '16 F. Hand and S. Filler, Beitr. Klin. Tuberk., 103, 239-244 (1950). 

 "6 Y. Miura, /. Biochem. (Japan), 37, 387-395 (1950). 

 1" R. J. Dubos, /. Exptl. Med., 92, 319-332 (1950). 

 "8 G. Weitzel, Z. physiol. Chem., 290, 252-265 (1952). 



