257. Demands On Food For Milk Secretion

As the secretion of milk is wholly dependent upon the mother's food, unless she is underfed and contributes from her body substance, her nutrition is a matter of fundamental importance. All considerations of this phase of the nourishment of the child must be based upon the amount and composition of the milk which it consumes. Authorities who have investigated this matter are somewhat at variance in the figures which they give for the milk secretion of the human mother. If it is measured by what the infant takes, and there is no unused surplus artificially drawn, an average amount is probably 300 grams (10.6 oz.) daily for the first week and at the end of the fifth month not far from 1000 grams (35.5 oz.) daily.1 If this milk is of average composition, it would contain in each day's production at the two periods approximately the dry matter and ingredients stated as follows: 1 See " Des Kindes Ernahrung," pp. 351-353.

Table XLVIII. Solids In Mother's Milk

The increase of milk secretion seems to correspond to the increased demands of the child, and proceeds with a fair degree of regularity. In those cases where more than one child is suckled, the daily production sometimes becomes much greater than when only one child is at breast, rising in observed instances to 1750 grams (62.5 oz.) or more daily. Under ordinary circumstances with one child the mother is likely to be called upon to supply on the average about 800 grams of milk daily from the fourth to the twentieth week. This milk, if of average composition, would contain 94.6 grams dry matter, 1.6 grams ash, 12 grams protein, 54.4 grams sugar, and 26.4 grams fat, the combined energy of these nutrients being 518 calories. These facts are convincing evidence that the demands on the mother during the nursing period are much greater than during the period of pregnancy, indeed, they are demands that should receive adequate recognition in the mother's diet, especially after the first few weeks.

258. Necessary Dietary

The American dietary standard for women doing light muscular work is 2400 calories, and with women doing moderate work it is 2700 calories. If the food equivalents of these energy expenditures are necessary to maintain ordinary household activity without gain or loss of body substance, the additional demands of the nursing child require that the food consumed shall be increased one-fifth, or even more, as the child increases in size. It is often noticed that nursing mothers grow " thin," which is undoubtedly due to insufficient nutrition, especially when the milk secretion reaches 1000 grams or above that quantity, the dry matter of which represents not less than one-fourth the daily ration of a housewife doing light work.

259. Effect Of Insufficient Diet

The physical welfare, not only of the nursing mother, but also of her child, is dependent upon her proper nourishment. Observation indicates that when the mother's diet is insufficient, the milk is less in quantity and possibly poorer in quality. The failure of an infant at breast to grow as it should may sometimes be due to lack of sufficient food, and this possibility should receive careful attention. It should not be assumed, however, that in all cases the necessary milk secretion can be secured through abundant diet. Certain mothers seem to have constitutional limitations of capacity to secrete milk that cannot be overcome by a generous diet, or by the kind of diet.