Human milk for the premature infant.

Closer study of premature infants has led to the establishment of human milk as the recommended nutritional standard for them. Infants fed with human milk are found to gain protection against necrotizing enterocolitis, and have fewer upper respiratory tract infections and systemic infections. Antibacterial components of human milk include leukocytes (macrophages, granulocytes, and T and B cell lymphocytes), the B cell secreted immunoglobulins, and complement factors. Lactoperoxidase and lactoferrin in breast milk are particularly active against group B beta hemolytic streptococcus and staphylococcus, respectively. Fresh human milk helps in the colonization of the infant's gut by Lactobacillus bifidus, a bacteria that suppresses other possibly pathogenic organisms. Nutritional values of human milk offer certain advantages and disadvantages over cow's milk. The quality of human milk protein is superior to that of cow's milk, and human milk's higher levels of cystine are especially required in the premature infant, where the liver is deficient in the enzyme required to convert methionine to cystine. Human milk is low in certain essential electrolytes and trace elements, such as sodium. It can also harbor drugs, pollutants, and harmful viruses that can be dangerous to the infant. Freezing of human milk for banking can destroy many of the immunological advantages of its use. Given that the advantages seem to outweigh the disadvantages, the authors favor the use of human milk for premature infants.