FACTORS INFLUENCING B VITAMIN REQUIREMENTS 297 



It is unnecessary, however, to consider strange food sources to find 

 such effects. Gross dietary distortions in a normal dietary regime may 

 bring such quantities of an apparently innocuous substance into the diet 

 that effects which are usually too slight to measure become important. 

 Thus the addition of various quantities of roasted coffee to the diet of 

 rats and dogs produced in the dogs diuresis, catharsis, weight loss, flaccid 

 paralysis, greying of the hair, an eye condition, and convulsions; and 

 produced alopecia, weight loss, edema, and death in the rats. 178 In dogs, 

 inositol appeared to cure the paralysis, and biotin cured the "weepy 

 eye" symptoms. The curative properties of inositol and whole liver were 

 not, however, complete in the rat. The alopecia in the rat appears to be 

 due to the caffeine. The similarity of caffeine to various other purines 

 involved in metabolism (and the known presence in coffee of a wide 

 variety of other analogues of B vitamins and other metabolites) might 

 suggest the existence of such toxic effects. 



Finally, new processing methods in food technology may result in 

 antivitamin effects by the production of synthetic antivitamins. Thus 

 the agenizing of flour (bleaching with NC1 3 ) forms products which have 

 been shown to be responsible for canine distemper, and it has been sug- 

 gested 179 that this is due to chlorination of the aromatic groups in the 

 gluten. Such chloro-amino acids are known to be inhibitors of amino acid 

 metabolism, and similarly modified B vitamins would be capable of a 

 similar effect. To date, fortunately, no such case has been reported. 



Influence of the Intestinal Flora upon the B Vitamin Requirement 



It has long been known that the microorganisms of the digestive tract 

 are in many cases able to synthesize many of the B vitamins, and that 

 these may well have a significant role in supplementing the nutritional 

 supply in order to meet the B vitamin requirement. Studies of this aspect 

 of vitamin nutrition have been numerous and extensive, but because of 

 the equivocal nature of the techniques available for such studies, the 

 results obtained have been at best qualitative, and frequently difficult 

 to interpret. Because of the uncertain nature of the results, the vast 

 amount of data bearing on the subject, and the presence in the literature 

 of excellent reviews on this topic, 180 " 181 it does not seem practical or 

 expeditious in this volume to consider the problem in detail. For this 

 reason, only a brief summary of the major points of interest is here 

 presented. 



Numerous studies have dealt at great length with the analysis of in- 

 testinal and rumenal flora, and the abilities of microorganisms to 

 synthesize the various B vitamins. Some organisms which are known to 

 synthesize specific B vitamins are listed in Table 15. Analyses have shown 



