Human Milk Studies

Publisher Website
Google Scholar
Abstract
The 10 essential amino acids were determined microbiologically in 38 samples of human colostrum and transitional milk secreted 2 to 10 days post partum. Samples were obtained from 10 women, each representing the composite mammary secretion from both breasts during 24 hours. The amino acid concentrations per 100 ml of secretion varied with subject and day post partum and did not parallel changes in volume of secretion or concentration of total solids. Total nitrogen and amino acid concentrations followed the same general pattern, with highest values occurring on the 5th, 6th, 7th, or 8th day post partum. The ratios between the nitrogen of the essential amino acids and total nitrogen were not consistent, indicating the possibility of shifting proportions of the casein, lactalbumin, and globulin fractions of the total protein. The same amino acids were determined in 133.6 ml of “first” colostrum, consisting of from a few drops to 4 ml of the first fluid from the breasts of each of 70 women, 8 to 24 hours post partum. Composites were also analyzed of the colostrum obtained from many of the women the first day and the second day following collection of the “first” secretion. In the “first” colostrum values for total solids, total nitrogen and the 10 essential amino acids were much higher than any values for human colostrum found in the literature. The percentage of total nitrogen represented by the amino nitrogen of the essential amino acids was higher than the corresponding values for the 24-hour collections of colostrum 2 to 10 days post partum. The greater percentages of amino nitrogen in the composites were accounted for by significantly higher values for arginine and threonine.