Human milk is secreted for the use of the human infant and under normal conditions, in healthy mothers, will be secreted in sufficient quantity, and proper quality and over a sufficiently long period of time, to supply the entire milk-needs of the infant.
The secretion of the breasts during the first few days after birth is somewhat different to ordinary milk and is called colostrsum. It is scanty in amount, thicker than milk and of a deep lemon-yellow color. Its chemical composition differs greatly from that of the later secretion. It is supposed to have a laxative effect upon the child.
Colostrum changes gradually into true milk which is thinner and bluer. The flow of milk is usually well established by the end of the first week while the complete change is finished by the end of the second or third week.
As the child grows the secretion of milk gradually increases in response to his demands. Much of the milk is actually formed while the baby nurses and is secreted in proportion to the vigor, strength and persistence with which he sucks.
The complete emptying of the breast each time he nurses is the most effective means of increasing the production of milk. If the breasts are not emptied each time, the secretion of milk gradually decreases. Farmers and dairymen have known this fact, with relation to cows, for ages. Some women like cows, give more milk than others, but aside from this the amount of milk secreted depends very largely upon the demands of the baby-- Increasing when more is consumed and decreasing when less is taken.
Human milk resembles cow's milk but differs from it in several important particulars. It is much sweeter than cow's milk, has no odor, and varies in color from a bluish white to a rich, creamy yellow. However one cannot judge of the quality of milk from its appearance, for the yellowest milks owe their color to a substance called carotin which is found in certain vegetables used for food.
The composition of human milk is very much the same throughout the whole of the nursing period. The greatest variation is in its protein content which diminishes as time passes. However, the composition of the milk varies from day to day and even from one feeding to the next, as well as from the beginning to the end of each nursing.
Human milk, on an average, contains about 7 per cent milk sugar, 3 to 4 per cent fat, 1.50 per cent protein, and 0.20 per cent of salts. The percentage of whey or soluble proteins in human milk is much greater than in cow's milk. Its salts are in a form much more easily utilized by the baby than are those of cow's milk. There is sufficient of these salts for the baby's needs except that of iron. But since the child is born with a good supply of iron stored in the liver, it does not suffer, at least for many months, due to this deficiency. This is, indeed, a remarkable instance of the precise adaptation of the milk to the needs of the child.
Analyses of mother's milk to determine its quality are of no practical value unless the whole of several nursings are used. Samples taken in the evening are likely to be different from those taken in the morning. At the beginning of the nursing the fat in the milk varies from 2 to 3 per cent, at the end of the nursing it varies from 6 to 10 per cent.
Considerable variation in the composition of the milk of various women is found. But babies thrive well on all of these. A baby that was thriving well on its mother's milk will thrive equally as well on the milk of a wet nurse. It is also true that one baby may thrive well on milk which, for some reason, another baby failed on. A baby may even take the milk of several wet-nurses and thrive well on all of them.
There can be no absolute standard for good milk. Unless some extreme variation exists, chemical analysis of the milk cannot determine its fitness or unfitness for the baby. Most of this laboratory monkey-work is just part of commercial medicine.
There is only one test for the adequacy or inadequacy of milk and this is the feeding test. If a child is growing normally and thriving on the breast milk it is receiving, it is quite evident that the supply is adequate But if it is not growing it is possible that the supply of milk is insufficient.
The amount of milk the baby receives may be determined by weighing it before and after nursing. Usually the baby receives one-half of its meal during the first five minutes of sucking. During the second five minutes it gets an added quarter of its meal.
There are only two ways of increasing the supply of milk--namely, an improved diet, and the complete emptying of the breasts at each nursing.
Water drinking will not help. There are no drugs to be taken internally or applied locally and no patented foods that will stimulate milk production.
Eating large quantities of rich foods is useless. These only derange digestion and destroy the mother's appetite. The one class of foods that greatly increases milk production in animals, and there are reasons for believing they will do so in woman, are green foods. An abundance of these should be eaten.
Prof. McCollum says: "There is good reason to believe that the common practice of confining the diet to too great an extent to bread, meat, sugar, potatoes, beans, peas and breakfast cereals (before birth and during the nursing period) is in no small measure responsible for the failure of many mothers to produce milk of satisfactory quantity and quality for the nutrition of their infants. There is no great hardship (but great benefit) in the restriction of the intake of meats, etc., and the increase of milk, fruits and green vegetables, and the mother who does so will greatly minimize the danger of a break In the healthy growth of her baby."
Dr. Page says:- "The woman who lacks a reliable appetite for any sort of plain wholesome food, is not a well woman; if she indulges in that which is unwholesome, she cannot maintain good health; if she is overfed, abnormally fat and plethoric, she is a sick woman; and such mothers cannot supply a perfect food for the nursing child." "Much sloppy food, hot drinks, profuse drinking between meals 'to force the milk,' are injurious to both mother and child. Much animal food is not advisable either in winter or summer, and in the latter season especially should be avoided altogether." "Nausea, lack of appetite, fitful appetite, 'gnawing' at the stomach--the latter so generally mistaken for a demand for food--all result from excess or the use of unwholesome food or condiments."
In treating of the causes of rickets, Dr. Eric Pitchard, of England, notes that the diet of the English is deficient in the alkaline minerals and contains an excess of acid radicals. Commenting on the effects of this upon nursing he says: "It is also worthy of note that, concurrent with the deterioration of teeth in this country (England) there is to be observed a decreasing ability on the part of mothers to suckle their infants. The production of milk entails an extraordinary drain on the calcium resources of the body; when these resources are depleted, the inability to produce milk is a natural sequence."