290 AJSTSrXJAL REPORT SMITHSONIAN INSTITUTION, 1942 



must realize that plant and animal products as produced on the 

 surface of this earth do not necessarily contain the individual 

 nutrients in optimum concentration for the human being. We must 

 use some ingenuity in compounding natural food materials into a 

 complete diet. Improvement in the quality of certain food supplies 

 will not only conserve total quantity of food but will tend toward 

 more optimum nutrition of all indviduals. 



Our problem today centers around the restoration and fortifica- 

 tion of foods. I should like to mention in passing that the interest 

 in this problem is undoubtedly stimulated by our national defense 

 program, but we should also recognize that we have reached a stage 

 in our knowledge of nutrition which makes it possible for us to 

 consider this problem. At first nutrition workers recognized that 

 certain foods were excellent sources of specific nutrients. These 

 foods became known as protective foods and we relied on these spe- 

 cific foods to a considerable extent for our supply of essential factors. 

 Wlien we recognized that inorganic salts were utilized as readily by 

 the body as the mineral elements found in our natural foods and that 

 synthetic vitamins could be produced at a fairly low cost, consider- 

 able interest was shown in the use of concentrates or capsules to sup- 

 ply some of the more important nutrients. The value of these prep- 

 arations in the clinical treatment of deficiency diseases cannot be 

 denied, but we must recognize that the administration of such con- 

 centrated forms of nutrients should be only temporary in nature. 

 If large groups of people are living on combinations of natural foods 

 which do not supply the total requirement, the food supply should 

 be modified or fortified. 



As the chemists showed greater interest in these problems, meth- 

 ods of assay have improved so that we can analyze our staple foods 

 for their vitamin content. These foods are not devoid of vitamins, 

 as many would have us believe, but show a low content on the per- 

 centage basis. If we multiply the amount present by the total 

 weight of the food consumed daily we find that the result may be 

 an appreciable part of the entire requirement. I am sure that in 

 the future we will look back upon this work as one of the most im- 

 portant periods in nutritional research. 



It is obvious that values for the distribution of nutrients in foods 

 are not of much use until we know the requirement for each of these 

 nutrients. If we had all these values available it would not be very 

 difficult for the dietitian to handle the food supply so as to give us 

 adequate nutrition through the use of pleasing foods. 



The establishment of nutritional requirements has also had a 

 rather interesting history. In a few cases the actual requirement has 

 been studied on human beings. Thus we have a considerable number 

 of data for the energy requirement of human beings of different ages. 



