The growing importance to manufacturers, dealers, and consumers of a knowledge of food products has led to the preparation of the following manual.
Unfortunately, many misleading statements respecting the composition of foods, their nutritive value, and their relation to health and digestion have been published and received with more or less credence by the public. Claims of superior excellence, which are entirely baseless, are constantly made for certain food products in order to call the attention of the public more directly to their value and, unfortunately, at times to mislead the public with respect to their true worth.
It is not uncommon to see foods advertised as of exceptional quality, either as a whole or for certain purposes. Many of the preparations of this kind are of undoubted excellence, but fail to reach the superior standard or perform the particular function which is attributed to them. Particularly has it been noticed that foods are offered for specific purposes or the nourishment of certain parts of the body, especially of the brain and nerves. We are all familiar with the advertisements of foods to feed the brain, or feed the nerves, or feed the skin. It is hardly necessary to call attention to the absurdity of claims of this kind. One part of the body cannot be nourished if the other parts are neglected, and the true principle of nutrition requires a uniform and equal development and nourishment of all the tissues. It is true that many of the tissues have predominant constituents. For instance in the bones are found large quantities of phosphate of calcium and in the muscles nitrogenous tissues dominate. In the brain and nerves there are considerable quantities of organic phosphorus. All of these bodies, however, are contained in normal food properly balanced.
It would be contrary to the principles of physiology to attempt to feed the bones by consuming a large excess of phosphorus in the food or the muscles by confining the food to a purely nitrogenous component. Such attempts, instead of nourishing the tissues indicated, will so unbalance the rations as to disarrange the whole metabolic process, and thus injure and weaken the very tissues they are designed to support.
It seems, therefore, advisable to prepare a manual which may be used in conjunction with works on dietetics and on physiology and hygiene and yet of a character not especially designed for the expert.
