332 IOWA DEPARTMENT OF AGRICULTURE 



FOOD VALUE OF MILK 



"Why are dairy products so important foods?" "Why are 

 they essential to health and growth?" "Why are they economical 

 foods?" These are typical and logical questions asked by those 

 wh( want to know the truth about food economy or those who would 

 feed themselves or their family well and economically. To answer 

 these questions intelligently we must understand of what a proper 

 diet must consist, that is what must be contained in the food 

 which we eat to supply the body with the various kinds of materials 

 required to support growth, supply energy and keep the body vig- 

 orous. 



Years of study and experimenting show that five different kinds 

 of food materials or food constituents are essential in an adequate 

 ration. These are energy producing materials, (the fats and car- 

 bohydrates) satisfactory proteins, suitable mineral matters, and 

 two substances, the exact nature of whicli is unknown, called vita- 

 mines. All these food materials are necessary and one kind can 

 not- be substituted for another as each has a definite function to 

 perform. An adequate quantity of each of these materials must 

 be present in the ration in order that it be satisfactory. 



All food stuffs contain more or less of one or more of the essen- 

 tial food constituents but milk is one of the very few foods which 

 contain all of them in suitable proportions. In the case of many 

 of our foods one or more of the essential food constituents are of so 

 poor quality or are present in so small quantity that they are not 

 found satisfactory for meeting the needs of the body of the growing 

 child. Milk, however, does contain the proper kinds in suitable 

 proportions and that is why milk promotes rapid growth and one 

 of the reasons why it is a superior and important food. 



Formerly nutrition experts considered that to formulate a satis- 

 factory diet, it was necessary to consider only the amounts of diges- 

 tible energy producing materials and digestible protein material 

 which the foods entering the ration contain. Little thought was 

 given to other constituents as in the ordinary mixed diet there is 

 usually sufficient mineral matter, the only other diet essential then 

 thought necessary. The error of formulating diet on this basis is 

 now apparent. A satisfactory diet can not be composed of fats, 



