XI. EEQUIREMENTS 383 



efficiently man can utilize the inositol of phytic acid is not known, but on 

 the basis of investigations in various species of animals it is probable that 

 appreciable amounts of phytic acid may be hydrolyzed in the human 

 intestinal tract. The enzymic cleavage of phytic acid in the intestinal 

 tract would be determined, at least in some measure, by the type of grain 

 ingested, for certain grains such as wheat,'" rye, and barley contain phytase, 

 whereas oats and maize do not.^ Cruickshank and his associates," in their 

 observations on four adult subjects, consuming a diet rich in oatmeal, 

 noted that the phytate P of oatmeal was almost completely digested when 

 the calcium intake was normal. Additional calcium decreased the digesti- 

 bility of phytate P if the supplementary calcium was taken together with 

 the oatmeal and not if it was taken separately. Sonne and Sobotka'^ noted 

 moderate increases in the concentration of the blood from average levels of 

 0.37 to 0.76 mg. per 100 ml. when 1.5 g. of inositol was administered orally. 

 Definite data on utilization and on possible synthesis of inositol in the 

 human organism as well as on the effect of other constituents of the diet 

 on the requirements for inositol are not available. For the present, these 

 questions can be answered only by inference based on data obtained in 

 animals. 



Anderson'^ found inositol to be absorbed very slowly from the intestines 

 of the dog and was able to recover in the feces as much as 77 % of the ad- 

 ministered amount. He noted that the urine contained only minimal 

 amounts. It would appear that the differences between his findings in the 

 dog and in man^ might be explained by the fact that in the dog inositol 

 produced diarrhea, but his findings in the dog were corroborated by 

 Dubin.^'* However, it should be noted that Bly et al}^ found inositol to 

 act as a cathartic. Greenwald and Weiss,'^ who administered inositol to 

 dogs with phlorhizin diabetes, found increases in urinary glucose that sug- 

 gested most of the administered inositol had been utilized. 



C. INFLUENCE OF OTHER CONSTITUENTS OF DIET 



A. T. MILHORAT 



Considerable evidence has accumulated indicating that the composition 

 of the diet influences the requirements for inositol. Thus, Best et al}'' 



«» R. J. Anderson, /. Biol. Chem. 20, 475 (1915). 



" E. W. H. Cruickshank, J. Duckworth, H. W. Kosterlitz, and G. M. Warnock, /. 



Physiol. (London) 104, 41 (1945). 

 " S. Sonne and H. Sobotka, Arch. Biochem. 14, 93 (1947). 

 " R. J. Anderson, /. Biol. Chem. 25, 391 (1916). 

 "H. Dubin, J. Biol. Chem. 28, 429 (1916-1917). 



15 C. G. Bly, F. W. Heggeness, and E. S. Nasset, ./. Nutrition 26, 161 (1943). 

 18 I. Greenwald ar^ M. L. Weiss, /. Biol. Chem. 31, 1 (1917). 

 " C. H. Best, C. C. Lucas, J. H. Ridout, and J. M. Patterson, /. Biol. Chem. 186, 



317 (1950). 



