Date on Master's Thesis/Doctoral Dissertation
Vitamins in human nutrition
In the bulk of experiments on animal feeding the Albino Rat has served as the experimental animal. It has been proved that any diet which brings about satisfactory growth in white rats will also cause a young child to grow satisfactorily. Therefore, much attention is given to the breeding of such rats for experimental and scientific use. In the earlier stages of experimental work it was found that a diet which contained sufficient protein material and which yielded the proper number of calories because of the fat, sugar, and starch present, was a satisfactory diet. Later investigations showed that animals fed on diets which corresponded in every respect to the diet mentioned above, did not thrive. The addition of certain mineral salts to the diet served to eliminate the trouble. This showed that a diet, in order to be adequate, must contain certain mineral salts in definite quantities. When the scientists began in intensive study of the protein substances from different sources, they found that they did not all possess the same food value. Some proteins produced normal growth and some did not. Due to this fact, to-day we divide the proteins into three groups – Complete, Partially complete, and Incomplete Proteins. If an animal is fed on a diet, of which the protein quota is made from the incomplete proteins, it will not grow normally. A great many of our foods that nature gives us in abundance have present in them incomplete proteins. Up to this time nothing but the solid constituents of the diet, that is, the fats, carbohydrates and protein had been emphasized. However, the importance of the liquid side of the diet came gradually to be appreciated. Water was quite essential for life and is of material assistance in the body processes as digestion, absorption, and excretion. Through a series of years and by means of many carefully controlled experiments the scientific opinion was to the effect that a diet was adequate if it consisted of the proper amount and kind of carbohydrate, protein, fats, mineral and water. It did not take long, however, for experimenters to find out that diets made up according to the above standard did not always yield satisfactory results. Quite a bit of work was done in these years and there were times when one scientist could not verify the results of another scientist. Finally, in recent years and after much research, it was definitely decided that normal growth could not be obtained on the above mentioned diet. In order that an animal should show normal growth and be free from certain disorders, its diet must contain certain substances which are called accessory food substances or vitamins.
Lovelace, Ruth, "The influence of a high and low vitamin content in nutrition." (1927). Electronic Theses and Dissertations. Paper 858.