On the other hand, many experiments on animals have shown the evil effects of an excess of the latter kind of food, which causes a very rapid deterioration in the physical life, especially in the lining cells of the alimentary tract and seriously interferes with the digestive and absorptive processes, so that the foods are not completely absorbed, assimilated and transformed into life tissues. For instance, a dog, if fed largely upon rice, will not have sufficient structure-building material, and a fatty degeneration will take place in the mucous-membrane lining of the alimentary tract, so that if this diet is continued very long the absorptive power in the alimentary tract will become so impaired that the animal ultimately will not thrive even if its natural diet is restored.
There are many food elements which are necessary to the integrity of the bodily tissues. For example, there is no animal life in which phosphorus does not play an indispensable part; and, if we should eat food which does not contain any of the phosphorous compounds, life would rapidly decline. The brain would quickly deteriorate if deprived of phosphorus, which is found abundantly in the yolks of eggs, in fish, in milk, cheese, etc. Cereals and legumes also contain much phosphorus.
Most people, especially the poor, eat more than twice as much starchy food as is required by the system; and, as they do not get enough of other foods, some of their tissues are starved. Those who live largely upon the products of fine flour overtax that part of the digestive system which takes care of the starchy food, and they often suffer from an overacidity of the stomach and sometimes of the saliva, which latter is very injurious to the teeth.
Children, of the poor are often born with rickets, because the mothers have lived mainly on white bread and tea and have not themselves had sufficient bone-making material to transmit to their children for the building of their skeletons. Some of these children have not enough backbone to hold up their heads, and they become deformed in all sorts of ways,—if they ever reach maturity,—because after they are born they do not get enough of the material they lacked before birth to build up and remedy their defects. A child needs much phosphorus, lime, magnesia, and silica for his skeleton, which is the principal part of his little body, and he should be nourished with the object of growth in view. Yet many children are fed chiefly on fine white flour products and tea, and often coffee. It ought to be regarded as a crime to feed children on such things!
No infant can digest solid foods until it cuts its teeth. Children should have plenty of milk until they are eight or nine years old, otherwise the bones will not get sufficient lime and other earthy salts to harden them, and rickets or bone diseases of some sort are likely to develop. While the body is in process of construction, all the tissues require a great deal more building material than when it has reached maturity, and milk contains everything necessary for early body-building. It is the only perfect food, and contains forty different substances. For proper development it is imperative to have every tissue in the body nourished, and to have every element in food which can build the tissues, furnish the fuel for combustion, and supply heat and the various energies for all the bodily activities. Some food authorities go so far as to say that drinking milk is almost like drinking blood, because, if pure and rich, it is such a great blood maker.
While milk is the only food which contains every element that enters into the human body, such as oxygen, hydrogen, nitrogen, carbon, phosphorus, sulphur, etc., yet taken alone it is not so well suited for an adult as for a growing child, because it contains too much building material, although that is the most important factor before the body reaches maturity. Later in life there is not much body building, but we require food for maintaining and sustaining the body already built. At the same time, a certain amount of milk, or its equivalent, is needed all through life; and, in some cases of weak digestion and certain other ailments, a diet composed almost wholly of milk has had very beneficial effects.
Our diet should be chosen according to our individual needs, as determined by our age and our vocation. It should be planned to enable us to express the maximum of our ability, our efficiency, in whatever line of endeavor we are engaged, whether it involve mental or muscular effort. Yet in some families there are half a dozen members who represent different vocations, but who eat the same kind of food. Our system of eating is as vicious as our system of education, where thousands of students are put in the same education mold, with little or no regard to their individuality, to the fact that no two of them are alike, that their temperament, their inherited tendencies, their degrees of physical strength and vitality are all different. Of course, this does not mean that a separate meal would have to be provided for each member of the family, which, in the majority of cases, would be impossible. As in education, the basis could almost invariably be alike; but there would be minor differences which, while they would not overtax the housekeeper, would make a great difference in the well-being of the family.
We have heard a great deal from time to time of concentrated nourishment; that is, of a large amount of nutriment in very much less bulk than in ordinary food forms. But it is not sufficient merely to take into the stomach just the quantity of nutrition which would keep the body in perfect food balance. It must be taken in a form adapted to its digestion and assimilation. For instance, it would not meet the requirements of nature to take food into the body in a very concentrated form, as in tablets. The stomach is a sort of bag in whose lining is contained follicles which secrete the gastric juices. When empty, this bag is closed up and is so contracted in size that if the food were taken in a very small bulk, it would not be sufficiently distended to perform its function, even though the small quantity of food contained every element necessary for body building. In order to enable the gastric follicles in the stomach lining to do their normal work there must be a certain amount of pressure upon them, and this can only come from the presence of a sufficient bulk of food to open up the stomach bag to its natural size. The action of the follicles is induced by the alternate contraction and expansion of the circular and longitudinal layers of stomach muscles. This churning motion of the stomach is necessary for the proper mixing of the foods which the gastric juice is cutting up, dissolving, and macerating. When the whole contents are thoroughly mixed by this churning process, the liquid mass is ready to pass on and receive the other gastric juices of the bile, the pancreas, etc., along the intestinal tract, where the chief part of the digestion is done, for the work of the stomach is chiefly mechanical.
This is one reason why animals like horses require hay with their oats or corn. The latter alone would not make sufficient bulk to insure perfect digestion. In some countries clay and earth are mixed with food in order to give a greater bulk to satisfy the requirements of the stomach. It also, in part, accounts for the fact that milk alone would not be an adequate diet for an ordinary adult. When it is taken alone, some twenty per cent, of it is lost through faulty assimilation, so that something like a gallon of milk would be required daily for the complete nutrition of an adult. Where, however, bread is taken with it, assimilation is much more perfect; so that, although milk is the only food that contains the elements necessary for building and maintaining the tissues of the body, because of its faulty assimilation when not mixed with other foods, and also because it would not make sufficient bulk in the alimentary canal for the purpose of digestion, it would not of itself make a practical or satisfactory diet for a healthy adult.
Most people look upon milk as merely a drink, but it is not; it is a food, and hence it is very bad to drink it as rapidly as water, as most of us do. When one drinks a whole glass of milk at a draught or two, it forms into a large, solid mass of casein in the stomach; whereas, if sipped slowly, there are many little casein balls instead of one, which greatly facilitates the process of digestion. Many people have severe pains in the stomach after rapidly drinking a glass or more of iced milk in very hot weather, or when the body is for any reason overheated. The shock to the warm stomach of this mass of iced milk is really dangerous, as the work of digestion can be carried on with efficiency only when food is at the temperature of the blood—ninety-eight and one-half degrees.
Perhaps, everything considered, eggs, next to milk, come nearest to being a perfect food; although, as in the case of milk, if we should attempt to live on eggs alone we would not be able to maintain the bodily balance or poise, which is the object of a correct diet. They are especially good for building up the brain cells and the cells of the nervous system generally,