FOOD. Commonly speaking, foods those substances eaten or drunk' for the ing up and maintenance of the human boa' and to supply enerari for its activities. In more exact scientific sense, only those uents of the foods consumed which are atm_ assimilated are considered foods : the no assimilable constituents being regarded as was!: Some scientific writers classify air as a but generally the term is limited to the ,: stances taken into the stomach in eating all drinking.
The processes of assimilation are discus. in the article NUTRITION, and the scientific seie tion of foods for specific purposes in the arty DIETEncs.
There have been several different classifia tions of foods, from various bases. The tms practical seems to be that which is used in study of Nutrition and Dietetics. This greP ing is first broadly into Inorganic and Organ foods, referring to their origin in nature.
The inorganic foods are: water, and mineral salts. Water, indeed, may be regank as the most important of all foods, as it est stitutes nearly 70 per cent of the human irk and is an absolute necessity in the continuum of the processes which maintain the body. Tlx average amount of water consumed per dad about four pounds, much more than the weight of all the other foods combined.
Of the mineral salts, common salt (sod= chloride) is the one taken in largest quant:rr and the only one eaten in its natural sin Other mineral constituents of ordinary which are essential in the body economy, an lime, phosphorus, iron, potash, magnesia sulphur; and in much smaller quantities, iodine fluorine and silica.
The organic foods are subdivided into tam general sections: (1) carbonaceous foods, in which carbon is the principal element; (2) nitrogenous foods, in which nitrogen is the element of chief importance; and (3) carbo nitrogenous foods, in which both carbon and nitrogen are contained in notable proportions.
Carbonaceous foods include starches, sugars, vegetables, fruits and fats. Nitrogenous foods include lean meats and eggs. Carbo-nitrogenous foods include the cereals, leguminous seeds (as peas, beans, lentils, etc.) milk and its deriva tives and nuts.
The pure starch foods in common use are cornstarch, tapioca, sago and arrowroot.
The sweet sugars are derived from the juices of the sugar-cane and the sugar beet, and the sap of some varieties of the maple. The sweet less sugar known as corn syrup, or glucose, is obtained from the starch of corn by chemical process.
Vegetables fall naturally into two groups: the roots and tubers, in which the food ma terial is stored in a more or less enduring form; and the so-called °green)) vegetables, which are perishable, and must be consumed while fresh.
In the first group will be sweet potatoes, white potatoes, parsnips, onions, beets, turnips and carrots. The second group will contain
cabbage, cauliflower, the several kinds of •sprouts,)) green peas and green beans, spinach, asparagus, rhubarb, etc. With these are usually grouped squashes, tomatoes and cucumbers, which, strictly speaking, are fruits, though served as vegetables.
The typical fruits contain more or less sugar, and the valued fruit acids, and besides, a con siderable proportion of starchy matters, as in the case of the banana. In the common dried fruits— dates, figs, raisins and prunes, the car bonaceous content is very high.
The fats, though classed with the carbo naceous foods, have so small a proportion of oxygen (as compared with the others) that they are sometimes put in a class by themselves, and called hydrocarbons. Besides the fats of the various meats, this group includes butter, cream, olive oil, cottonseed oil, cocoa and palm oils, and even cod liver oil, to be regarded as a food rather than a medicine.
The nitrogenous foods are chiefly the flesh of animals, birds, fish, shellfish, etc., and eggs. With these also belong the meat extracts and similar preparations.
The carbo-nitrogenous group includes the grains — wheat, oats, rice, etc.— and the flours, meals and special preparations made from them, including breads and crackers. Green corn be longs in this group, and also dried peas, beans and lentils and peanuts. All sorts of nuts are also included, though the nitrogen content of the chestnut and coconut is so low as almost to place them with the carbonaceous foods. Milk is put into this class because of its casein. This substance in the form of cheese is one of the most valued of the carbo-nitrogenous class, as, besides the nitrogen, it contains a large proportion of fat.
Among the liquid foods, or beverages, prep arations of tea and coffee are to be classed as stimulants rather than foods. Their food value is nearly all owing to the sugar and milk added to them. Chocolate and cocoa, however, possess large food values with a notable nitrogen con tent. Other articles of food are the condiments, spices and sweet herbs, which, while they have some small food value, are useful chiefly in rendering other foods more palatable. For an intimate study of the food question see the articles DIETETICS, and NUTRITION OF MAN.
Bailey, Chemistry and Use of Food Products' (1914) ; Carpenter, (Foods and their Uses) (1908) ; Carrington, (The Natural Food of Man) (1912) ; Chris tian, (Uncooked Foods and How To Use Them) (1904) ; Forward, Food of the (1904) ; Greer, (Food: What It Is and What It Does) (1915) ; Sherman, (Food (1914) ; Snyder, Foods) (1910) ; Vulte and Vanderbilt, (Food Industries) (1914).