The influence of diet on the chemical composition of the body. 1

Abstract

The investigation was an attempt to ascertain to what extent, if at all, the fundamental chemical structure of an organism can be altered by variations in diet or changed nutritive conditions. White mice were kept on dietaries of widely different character, e. g., high protein, protein and fat, low protein and carbohydrate, etc., during considerable periods of time, and then killed and analyzed. The data are being published elsewhere. They are interpreted to indicate that although the fat and water content of such organisms show variations through a very wride range, there is a constant interdependence, even in cases of malnutrition. High content of fat is accompanied by lower water content, and vice versa. When the water content of the body is calculated on the basis of the fat-free tissue, the range of variation is remarkably small (70 to 74 per cent. of water). In order to afford some direct basis for a comparison of the tissue substance aside from its water and fat and the inorganic skeletal structure, the nitrogen content of the entire animals was calculated on a water-, fat-and ash-free basis. With few exceptions the animals afforded figures within narrow range above or below 16 per cent. of nitrogen. The constancy of composition of the organism suggests that it is not possible ordinarily to upset the relative composition of the body by dietetic measures, aside from altering the fat and glycogen content. Normal growth proceeds only through assimilation of all the essential body constituents in the proportion in which they are normally found in the body; and in tissue disintegration the loss is likewise general, not restricted to individual components of the fundamental structure,