In point of quantity consumed, white flour is the most important article of diet of the American people, and is widely used in Europe. This is remarkable because it is notably deficient in more dietary factors than any other single food which enters in a large way into the diet of man, except sugars, starches and fats which are marketed in the pure state. Muscle meats are, however, almost in the same class. Bolted flour consists essentially of starch, proteins and inorganic salts. Its proteins are of relatively poor quality, and its mineral components are conspicuously lacking in calcium, sodium, chlorin, iron and phosphorus, some of the essential elements we regularly expect to find in satisfactory abundance in our foods (5).

The proteins of bolted flour are practically limited to two. These are called gliadin and glutenin, both of which are very unlike any of the proteins in the animal body from the standpoint of their yield of the different amino-acids. These proteins are not constituted so as to enhance each other's value as food by compensating each other's deficiencies, and cannot, therefore, be effectively transformed into body proteins unless they are combined with other foods wisely chosen (6). Wheat flour is very deficient in all three of the recognized unidentified dietary essentials, fat-soluble A, water-soluble B and water-soluble C, the anti-ophthalmic, anti-neuritic and anti-scorbutic substances, respectively (7).

The merits of flour as a food rest essentially upon the peculiar glutinous properties of its proteins, which make possible the formation of dough. This is sufficiently tenacious to permit of leavening by the generation of carbon dioxid gas within it, through the agency of yeast or baking powder. By this means light spongy bread is secured, which has a pleasant flavor, and a texture which invites mastication. Bread and meat are the only foods which are prominent in the American diet which are chewed to any appreciable extent. Of these, bread is by far the most important in this respect. Bolted flour possesses still another virtue. It has excellent keeping qualities and can be distributed without commercial hazard over wide areas from the milling centers. This is a matter of great importance in a country like the United States. It will, despite its shortcomings from a dietary standpoint, remain our most important energy-yielding food.

It is not to be understood from what has been said that wheat flour is not a wholesome food. When properly combined with such other foods as make a well proportioned diet, every factor of which is so adjusted as to meet the needs of the body, it becomes an entirely satisfactory part of the diet. The keynote to the discussion of the individual foods entering into the diet of man is the importance of using proper combinations of foods.