876 XIV. NUTRITIONAL VALUE OF FATS 



milk, the galactosuria could be completely prevented. These workers 

 suggested that fat may play a role in the metabolism of lactose and of 

 galactose other than by altering the rate of absorption. It was later 

 shown that several different synthetic even-chain fatty acids containing 

 twelve or more carbon atoms were equally effective in preventing the 

 excretion of galactose in the urine, when fed with skim milk.^^" In con- 

 tradistinction to this earlier work, Zialcita and MitchelP^^ were unable to 

 confirm the effect of fat as such on the metabolism of galactose. These 

 workers conclude that there is no reason which would lead one to expect 

 such an interrelationship. It was found In^ these latter investigators that 

 corn oil, but not butterfat, was able to decrease galactosuria by about 

 27% on a diet containing 48% of lactose. It was believed by Zialcita and 

 Mitchell that this effect may be due to some non-glyceride component 

 present in the corn oil. In a later communication of the Wisconsin group, 

 Geyer and co-workers ^^'^ extended the earlier work by employing skim 

 milk and synthetic diets containing lactose or galactose. It was concluded 

 that fat decreased the resultant galactosuria, and increased the utilization 

 of galactose. These conflicting viewpoints of the several obser\'ers leave 

 the question open as to whether the effect of fat on galactosuria originates 

 primarily in the absorptive or in the metabolic phase of the utilization of 

 galactose. Xieft and DeueP®^ attempted to throw some further light on 

 this problem. Their data strongly support the hypothesis that fat affects 

 primarily the absorption of galactose. It was suggested that the delayed 

 evacuation of the stomach due to the presence of fat might slow down the 

 rate at which lactose (or galactose) reaches the intestine; this would result 

 in a lower galactosemia, with a resultant increase in the proportion of the 

 sugar which is retained. When fat was fed at a level of 20% the relative 

 effectiveness of butterfat, cottonseed oil and corn oil, respectively, in re- 

 ducing the excretion of sugar in the urine was found to be identical. Al- 

 though favoring the theory that fat acts upon the absorptive phase of 

 galactose metabolism, Xieft and Deuel"'^ leave the question open as to 

 whether or not there is also some effect upon the metabolic phase. It 

 was reported earlier from the laboratory of these investigators that galac- 

 tose exerts a greater ketolytic effect than does glucose, in the case of both 

 rats^^'' and man."'^ Banerjee^^^ found that, although the glycogen and fat 



160 E. J. Schantz and C. F. Krewson, Proc. Soc. Exptl. Biol. Med., 42, 577-579 (1939). 

 '" L. P. Zialcita, Jr., and H. H. MitcheU, /. Nutrition, 30, 147-150 (1945). 

 '" R. P. Geyer, R. K. Boutwell, C. A. Elvehjem, and E. B. Hart, J. Biol. Chem., 162, 

 251-259(1946). 



163 M. L. Nieft and H. J. Deuel, Jr., J. Biol. Chem., 167, 521-525 (1947). 



1" J. S. ButtP, J. Biol. Chem., 105, 87-96 (1934). 



16* H. J. Deuel, Jr., M. Gulick, and J. S. Butts, J. Biol. Chan., f>S, 333-351 (1932). 



166 S. Banerjee, Proc. Soc. Exptl. Biol. Med., 77, 585-587 (1951). 



