EECENT VIEWS ON THE CHEMISTRY OF DIET* 

 By Isaac F. Harris 



Under the subject of diet we include all chemical substances 

 which have to do with the nutrition of man. Hall has defined 

 it as the physiological process of supplying the material needs 

 of the body. In a broad sense, it means food, drink and oxy- 

 genation. A mixed diet consists of non-diffusible proteins, car- 

 bo-hydrates and fats, and the function of the digestive process 

 is to break up these complex molecules into smaller, simpler, 

 soluble and diffusible ones, which are capable of absorption and 

 utilization by the body processes. The science of dietics in- 

 volves the knowledge of the chemical composition of the human 

 body and of the foods with which it is proposed to maintain and 

 repair it, and the sequence of chemical changes which the body 

 undergoes during the multiple processes of digestion and assim- 

 ilation. 



The nutrition of man is comparable to the fertilization of 

 a vegatable form. In the latter case we first observe the 

 chemical make-up of the plant and then look for a fertilizing 

 material which will best supply these elements. If the plant 

 has a high content of potassium, like the tubers, then we supply 

 potassium to the soil. If the case in point be man, with a high 

 content of nitrogenous, albumin-like tissue, then we must sup- 

 ply nitrogen in the diet. Furthermore, the supply of chemical 

 elements in the food must be in such combination or molecular 

 arrangement as to be available to the metabolic processes of the 

 individual to be fed. While plant life in general can derive 

 its nitrogen supply from the inorganic nitrates of the soil, man 

 can obtain his nitrogen requirement from protein or albumin- 

 like sources, only. McCollum says regarding a mixed, balanced 

 diet, " Unquestionably the physiological value of a ration is 

 largely dependent upon its chemical constituents, but the usual 

 determinations made on feeding materials do not reveal the 

 character or manner of combination of many of the constituents. 



*Read before the Jenkins Medical Association, Yonkers, N. Y., December 12tli, 

 1912. 173 



