DIET AND NUTRITION 



shown that in the digestion of meat in the normal stomach 

 something is formed which is indispensable to the proper 

 functioning of the structures in the bone marrow which 

 form red blood corpuscles. The capacity to produce this 

 substance is lost by the debilitated stomach of the patient 

 with pernicious anemia. It appears that this substance 

 formed in the stomach is largely absorbed in the intestine 

 and tends to accumulate in the liver; but a portion passes 

 on to the general circulation and tends to accumulate in 

 the kidneys. The kidneys are not so good as liver for the 

 relief of pernicious anemia, but are greatly superior to the 

 muscle cuts of meat. The fresh stomachs of pigs, when 

 ground and allowed to self-digest for a while before being 

 cooked, are highly effective as a source of the substance 

 furnished by liver. Several manufacturers are now putting 

 on the market concentrated extracts of liver which are as 

 effective as liver itself in improving the condition of the 

 blood of pernicious anemia patients. The nature of the 

 substance is still unknown. 



Supplementary Values in Proteins. Chemical analyses of 

 proteins isolated from various animal and plant sources 

 have revealed a surprising difference in their constitution. 

 Human muscle contains about 12 per cent of a digestion 

 product called glutamic acid. Wheat proteins yield as 

 much as 45 per cent of this substance. This is an example 

 of a food protein yielding an excess of one of the digestion 

 products. There are many illustrations of food proteins 

 yielding too little of one or more digestion products which 

 are necessary for the formation of body proteins. The 

 quality of the protein is determined by its content of that 

 indispensable amino-acid which is present in the smallest 

 amount. Because of the excess or deficiency in the yields 

 of amino-acids, most food proteins of vegetable origin 

 are not of very high quality — that is, these food proteins 

 cannot be transformed with high efficiency into animal 



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