Food Adjuncts and Drugs

The Chemistry Of Food and Nutrition
by A. W. Duncan, F.C.S.

(Page 6 of 11)

In addition to the nutrients and the small quantity of indigestible fiber of which we have already written, food generally contains small quantities of substances which are difficult to classify, and whose action on the body is but imperfectly understood. Many of these possess pungent or strong odors and flavors. To them, various fruits, meats, etc., owe much of their characteristic differences of taste.

When pure the Proteins and starches are devoid of taste. Such oils and fats as are generally eaten have also but little flavor, providing they are free from rancidity and of good quality. The sugars differ from the other nutrients in possessing a more or less decided taste. The free vegetable acids also strongly affect the sense of taste, but they are only consumed in small quantities.

A drug may be defined as a substance which modifies the functions of the body or of some organ without sensibly imparting nourishment. This action may be one of stimulation or of depression. A drug is taken for its medicinal action, a food adjunct for its modifying action on food. It is impossible to give a quite satisfactory definition, or to draw sharp distinctions. For example, tea, coffee, alcohol and tobacco are sometimes placed in one group, and sometimes in another, according to opinion of their action and the definition of the terms food adjuncts, drugs and poisons.

The difference of grouping often depends upon intensity rather than of kind of action. If taken frequently and not in quantity sufficient to have a markedly medicinal action, such things are generally called food adjuncts or supplementary foods, although much may be said in favor of a different view. The volatile oils of mustard, caraway, cloves, etc., are used in medicine; also the alkaloids of coffee and cocoa. Even honey is used as a mild laxative for infants; that is, as a drug. The difference between a drug and a poison is one only of degree. Some of the most esteemed drugs have to be administered in very small quantities, or they cause death; e.g., strychnine and morphine.

Classifications are necessary for methodical study, and for assisting the memory in grasping large numbers of things which can be grouped together. Classifications, however, are artificial, not due to natural lines of demarcation, but according to man's knowledge and convenience; hence a group is apt to approach and finally merge into another group, although on first consideration they appeared quite distinct. The disregard of this often leads to confusion and useless discussions.

Plants, like animals, as the result of tissue change, have certain used-up or waste matters to get out of the way. Animals have special excretory organs for the purpose; waste matter remains in the flesh and blood of dead animals. In plants are found a large number of powerful volatile oils, alkaloids, bitter resins, etc. Many of these are, in all probability, excretory products of no assimilative value to the plant. Certain volatile oils may attract insects, and in obtaining nectar from flowers insects assist fertilization. Agreeable volatile oils and flavoring substances in fruits attract birds and animals. The eating of the fruits cause the seeds, which are uninjured by passing through the digestive system, to be disseminated over wide areas to the advantage of the plant species.

On the other hand, nauseous and poisonous alkaloids, oils, resins, etc., serve as a protection against the attacks of browsing animals, birds, caterpillars, snails, etc. These nauseous substances are most abundant in the bark, husk, skin and outer parts. It is commonly supposed that the food on which each animal, including man, subsists, is especially produced by Nature for the purpose. This is an error, for each species of plant and animal lives for itself alone, and protects itself, with more or less success, against destruction by its competitors and enemies. Each species of animal selects from its surroundings such food as is most suitable.

Such food may not be theoretically perfect; that is, it may not contain the maximum of nourishment free from innutritious matter; but during the long period of evolution, each species of animal has become possessed of organs suited to its environment. If to such animals be given food containing less indigestible matter, or food which is more readily digested by laboratory tests made independently of the living animal, their digestive system will be thrown out of gear, become clogged up or refuse to work properly, just as the furnace of a steam boiler, made to burn coal, will act badly with wood or petroleum. Many scientific men have overlooked this fact, and have endeavored to produce food substances for general consumption, in the most concentrated and soluble form, thinking such food would be more easily assimilated.

Manchester the Vegetarian Society, 1905.