54 



also the cheapest kind of flour. It should not be inferred, however, 

 that the use of entire-wheat and Graham flour is to be discouraged. 

 All the flours are very nutritious and economical foods, and experience 

 has shown that they are wholesome as well. The difl'erences in the 

 amounts of total nutrients furnished the body by the various grades 

 of flour are comparatively slight, all grades being quite thoroughly 

 digested. 



In discussing the nutritive value of the breads made from the three 

 kinds of flour, the quite noticeable efl'ect of the breads upon the sub- 

 jects is of interest. In the experiments reported all the subjects 

 expressed a preference for the white bread. The Graham bread, when 

 it furnished the bulk of the ration for four days, produced a little 

 discomfort, suggesting a slight irritation of the digestive tract. The 

 ration of white bread and milk was less bulky in character and gave 

 • better results as to satiety and particularly as to ease of digestion. It 

 should be borne in mind, however, that the tendency of the coarser 

 flours to increase the peristaltic action of the intestines is often of 

 undoubted value, particularly to persons of sedentary habit, and that 

 their use as a laxative is in many cases extremely beneflcial. 



The use of difterent g-rades of flour for bread making is a convenient 

 means of increasing the variety of the diet. Because of varying 

 requirements no general rule can be laid down in the matter, and the 

 extent to which the various grades of flour should be used must be 

 determined largely by the individual himself. 



In this investigation the comparative digestibility of the phosphates 

 and other mineral constituents was not determined, nor were the quan- 

 tities consumed and the amounts and proportions excreted in the urine 

 and feces studied. As yet entirely satisfactory methods have not been 

 generally adopted for determining the digestibility of mineral constit- 

 uents, and consequently there is a lack of deflnite knowledge concern- 

 ing body requirements and the changes which are involved in the 

 metabolism of the ash constituents of the diet. Considerable work 

 along these lines is now being carried on by a number of investigators 

 in France and elsewhere in Europe, and in the United States studies 

 of the forms in which ash constituents, especially phosphorus, occur 

 in food products, methods of estimating phosphorus, sulphur, and 

 other ash constituents in food and excretory products, and various 

 problems concerning the functions of these elements are l^eing taken up 

 in connection with the nutrition investigations of this Office and by 

 experiment station workers and other investigators. It is believed 

 that this work maj' be more appropriately summarized when the 

 investigations now in progress have been continued for a longer time. 



