These are water, cellulose, minerals, and vitamines ; and they serve to keep the body machinery in running order.
Water constitutes two thirds of the weight of the body, and enters into the composition of all the tissues and fluids. It is one of the most important of regulating substances, as it equalizes the temperature of the body, serves as a carrier of dissolved food material, and prevents the accumulation of waste material. Life can be maintained for a much longer period without food than without water.
Cellulose is the woody, indigestible part of vegetable foods, and is needed because it supplies a bulk necessary to facilitate the movement of food along the intestinal tract. Some raw foods, such as lettuce, celery, cabbage, radishes, water cress, cucumbers, etc., may well be eaten daily, as these pass through the system largely as bulk, at the same time furnishing to the body their valuable organic salts unchanged by heating.
Vitamines are found in all natural foods, especially in the leafy vegetables, in milk, in the germ and the outer layers of grains, and in fruits. When the outer coat (the bran) is removed from the wheat, and the brown coat is removed from the rice, as is done in polishing, these otherwise wholesome and nourishing foods be-come devitalized, and will not support life unless foods containing the missing elements are added to the diet.