Neither human nor cow’s milk will meet the full nutritive needs of the infant during the first year of life. Several factors require consideration when planning for supplementary feedings.

Iron-deficiency anemia

It is perhaps the most common nutritional problem in the first year of life. Although supplementary foods furnish some iron the amount is usually not enough to meet the needs of the rapidly growing infant. Therefore, many pediatricians recommend that iron-fortified formulas be continued when the infant substitutes cup feedings for the bottle. Commercial infant cereals fortified with iron are preferable to family-type cereals that are not as highly enriched.

Salt

Babies, like adults, require some sodium and they respond to the taste of salt. During the early months the formula supplies most of the sodium intake. Thereafter, supplementary foods provide increasing amounts of sodium, often far in excess of needs. Nutritionists have criticized the excessive use of salt for two reasons: (1) the infant becomes accustomed to ingesting higher levels that are continued throughout life, a practice that may have some influence on the incidence of hypertension; (2) the intake of excessive salt increases the excretory load on the kidneys. The sodium level of most proprietary infant foods now comes within the levels recommended by a committee of pediatricians and nutritionists.

Over-nutrition

It is a relatively common problem during the first year, and sometimes sets the pattern for later obesity. It can be prevented by allowing the infant to take what he wants from his bottle feeding rather than urging him to finish it, and by using some moderation in the amounts of supplementary feedings that are given.

Many pediatricians believe that the early introduction of supplementary feedings contributes to overfeeding and excessive weight gain.

Skim-milk formulas should not be used during the first year to reduce the caloric intake. To meet the normal requirements for growth such formulas supply excessively high ratios of protein and carbohydrate. The high protein intake increases the load upon the kidneys for the excretion of nitrogenous products, and a high intake of lactose could contribute to diarrhea.

Baby foods

Most pediatricians recommend that semi-solid and solid foods be introduced at 3 to 4 months rather than at 6 weeks to 2 months as had been common practice in recent years. This delay results in fewer instances of excessive weight gain.

Many mothers derive much satisfaction from the preparation of foods for the infant. To do this successfully they must have an understanding of the methods for retention of nutritive values and for maintenance of sanitary controls. Also needed is the appropriate equipment for pureeing foods.

Commercially prepared baby foods are generally higher in cost than those prepared at home. For many mothers they possess these advantages; convenience; safety from bacteriologic contamination; variety; and uniform consistency and composition. The methods of manufacture currently employed result in the high retention of nutritive values, often higher than that achieved in home preparation. Nonetheless, the mother should be aware of the contribution each food makes to the baby’s needs. For example, a high-meat dinner will provide considerably less protein than the strained meat.

Sequence of feeding

Practices vary widely on the sequence with which foods are added and on the age of introducing these foods. Some babies need supplements earlier than others; some are ready for changes in texture sooner than others.

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GENERAL HEALTH

Immunity means the being free from the effects of something and, as generally used in medicine, this is freedom from infection by disease. The methods, with which the body works to accomplish this, affect other situations.

There is no doubt that many aspects of immunity are not understood by scientists; one well-known authority, in fact, says that our understanding of these matters is but that of children. It is self-evident that the writer of the treatise which you are reading cannot assimilate all the large amount of knowledge that these scientists have accumulated. By a sort of law of diminishing returns what is handed over to and taken in by you is bound to be sketchy, but it is believed and hoped that what you see as in a glass darkly is merely indistinct and not distorted.

Undoubtedly all persons are born with some, but varying, degrees of immunity to different diseases. For thousands of years their ancestors had been fighting disease in the body and if they had not developed an immunity they would have ceased to exist. This is called an inherent, or natural, immunity.

Then they acquire immunity in various ways. First is that which the mother passes on through the placenta. Thus measles, diphtheria, and chicken pox do not affect infants in the first few months of life. Their bodies are not making this immunity; it has been loaned to them by their mothers, and after a bit it disappears. This is called passive immunity. Other special immunities the mothers do not seem to pass on. It is notorious that infants do not get immunity to whooping cough.

Immunity refers to the ability which an individual possesses or acquires to resist or overcome infection. The body functions in several ways to secure the individual against invading bacteria. The blood carries with it at all times substances and special cells which help to combat bacteria and their poisons (toxins). If certain toxin-producing bacteria gain a foothold somewhere in the body and secrete their poison into the tissues, these poisons are absorbed and disseminated, by the blood and lymph, to bring death and destruction to certain body tissue cells; however, just as soon as this course of events begins, many factors operate to combat the invasion. The white cells gather about the invading bacteria and engulf and destroy them; in addition certain cells in the body respond to the toxin-producing bacteria (antigen) by producing antibodies which act in several ways to defend the body.

One kind of antibody (opsonin) affects bacteria in such a way that they are more readily picked up and destroyed by the white cells of the blood; another kind (antitoxin) neutralizes the specific kind of poison produced by the bacteria quite as an acid is neutralized by a base. A third kind of antibody (agglutinin) immobilizes the bacteria cells and clumps them so that they are more readily removed by the white cells. These substances and other antibodies are produced only when a foreign protein substance, as occurs in viruses, bacteria, and their toxins, gains entrance to the body.

The details of the ensuing skirmish or possibly great battle are complex. If the poison or bacteria win, the war is ended for that body. Fortunately most of us win innumerable skirmishes. These fighters which we enlist at short notice are so highly specialized that it will be necessary at this point to abandon the metaphor about a defending army. If a body is attacked by measles, the “antibodies,” as we call the resisting force, are of no value against pneumonia. Each kind of antibody defends against only one disease. But what a job some of them do in their narrow special line! You all know that there are a number of diseases, one attack of which gives immunity for life.

The enormous amount of antibodies that may be poured out in response to the poison of an infection is demonstrated in diphtheria. This was a terrific scourge a generation or so ago. Diphtheria localized itself on mucous membranes, usually in the throat, where a membrane formed; but it also produced a highly poisonous substance known as diphtheria toxin which circulated through the body. The antitoxin to combat it was obtained by injecting toxin into a horse; first a very small amount which the horse could stand. This dose was slowly increased until in six months the horse could take one thousand times the amount of toxin which would have killed him in the beginning. Then the antitoxin obtained from him, when injected into a child, proved a successful protection.

Years ago, when typhoid was still common, a friend of mine had an attack. Recently she planned to travel in Europe and she consulted me. Would her previous attack of typhoid make her immune to it? It has been generally understood that people did not have second attacks of certain diseases such as typhoid, smallpox, and measles. These surely did give long-lasting immunity. But now it has been found that second attacks may occur as the immunity weakens with time.

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GENERAL HEALTH