436 FORBES! MINERAL ELEMENTS IN NUTRITION 



found in 11 samples out of 32, more commonly among beans, 

 peas, and cowpeas than among soy beans. 



The manufactured foods, and milling and manufactory by- 

 products contained iodine in 13 samples out of 25; of those con- 

 taining iodine 10 were made from cereals. The offal portions 

 of the grains are apparently richer in iodine than the more starchy 

 parts. 



The more important sources of iodine in the human dietary, 

 then, are the garden vegetables, though some is also found in 

 the cereal foods and in several foods of animal origin, mostly 

 of the sorts less commonly used. 



Among the foods used by livestock the more important sources 

 of iodine are the hay, silage, and forage crops, and also the mill- 

 ing and manufactory by-products, comparatively little being 

 found in the natural grain foods. 



No consistent or orderly geographic distribution of iodine 

 in foods was revealed; nor were there noticeable effects of the 

 type of soil or method of fertilization on the iodine content of 

 foods. We found nothing characteristic in the iodine content 

 of foods from regions where goiter was especially prevalent. 

 The iodine content of samples of the same crop from different 

 plots of the same field sometimes varied greatly. 



The general conclusion from this study was that iodine is 

 a comparatively unusual food constituent and that its presence 

 is commonly accidental in the sense of standing in no essential 

 relation to the growth of the food products. Variations in the 

 iodine content of foods were not successfully correlated with any 

 associated conditions. 



It is possible that the total iodine requirement of the organism 

 is gleaned from foods containing so little of this element that its 

 presence would escape detection by our best methods of esti- 

 mation. It is also possible that the iodine content of the drink- 

 ing water is of greater importance in relation to the cause of 

 goiter than is the iodine content of the foods. 



The general effect of this study is to direct us elsewhere, 

 especially toward the metabolism of the organism, in our search 

 for the cause of goiter. 



