FATS AS ESSENTIAL DIETARY COMPONENTS 865 



prominent symptoms of deficiency, but that it is also demonstrated in the 

 absence of these two characteristic signs of the avitaminosis. On the other 

 hand, although rats can thrive on a diet free from vitamin Bi if it contains a 

 large proportion of fat or of protein, the oxidation of pyruvate is neverthe- 

 less defectiA'c, as demonstrated by Banerji and Yudkin'"^ with in vitro 

 tests of kidney sHces. The defective utihzation of pyruvate could be 

 corrected by the addition of vitamin Bi to the respiring tissue. The defect 

 was present in all animals depriAed of the vitamin, irrespective of the 

 presence or absence of other signs of deficiency. According to De Caro and 

 Rindi,^^" the hyperpjTuvemia of animals suffering from avitaminosis Bi 

 drops to the normal amount six hours after the feeding of fat (olive oil). 

 It is believed that this occurs because, under these conditions, the organism 

 metabolizes fats in preference to carbohydrates and proteins; the latter 

 foodstuffs give rise to pyruvic acid. In a further investigation of the 

 interrelations of thiamine and fat, Ivrider and Guerrant"^ found that the 

 increase in body weight of rats varied directly with the fat content of the 

 diet, and was not affected by the amount of thiamine fed when the intake 

 of the latter vitamin was 2 mg. or more per day. &'ider and Guerrant^^^ 

 reported that the increase in weight was due primarih^ to deposited fat. 

 According to Waisman and colleagues/^- the resistance of thiamine- 

 deficient mice to infection with Lansing poliomyelitis or Theiler's enceph- 

 alomyelitis virus can be explained only in part by the accumulation of 

 pyruA'ate or of other metabolites from incomplete carbohydrate breakdown. 

 The addition of 4% of sodium pyruvate to a complete diet containing 

 thiamine decreased the incidence of paralysis, but not to such an extent 

 as occurred in thiamine-deficient rats. It was found that the substitu- 

 tion of high -fat diets to prevent the formation of pyruvic acid was not 

 wholly effective, because fat apparently has little sparing action on thi- 

 amine in the case of mice. 



g. Bacterial Action. Since insuflEicient data are available concerning the 

 effects of lipids on microorganisms, the author preferred to discuss the 

 papers on the subject in more or less chronological order, rather than to 

 construct what could onl}^ l)e an incomplete system. ^^^ Fats, and es- 



'09 G. G. Banerji and J. Yudkin, Biochem. /., 36, 530-5-41 (1942). 



"» L. De Caro and G. Rindi, Nature, 167, 114-115(1951). 



"1 M. M. Krider and N. B. Guerrant, /. Nutrition, 41, 115-126 (1950). 



'•'' H. A. Waisman, H. C. Lichstein, and P. F. Clark, Arch. Biochem., 8, 20.3-210 

 (1945). 



^'* Nomenclature in bacteriology is rather confused, since there are so many S3^nonyms 

 for one organism. Insofar as possible the author has followed the system of nomencla- 

 ture used by 1). H. Bergey, Manual of Delerminalive Bacteriology, 6th ed., Williams & 

 Wilkins, Baltimore, 1948. 



