This issue of Breastfeeding Medicine is a gold mine of bench research involving human milk as described by Liu and Newburg
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in their in-depth review of the role of human milk glycoproteins (HMGP) in the protection of infants against human pathogens. As David Meyers
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so wisely said at the first Kellogg Foundation–sponsored Breastfeeding Summit in 2009, “The discussion is over.” Human milk is for the human infant because it is the specific nutrition and protection against disease. The discussion may be over, but the investigation of why human milk is so perfect must continue. Most of the more than 400 proteins that have been identified in human milk by mass spectrometry are glycosylated. Other mammals, including the cow, have glycoproteins, but they differ from those in human milk. They are tailored to protect their specific offspring. They do not protect the human infant. Liu and Newburg
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reviewed the works on HMGP, which include a long list of familiar constituents including mucins, secretory immunoglobulin A, xanthine dehydrogenase, bile salt-stimulated lipase, lactoferrin, lactoperoxidase, butyrophilin, lactadherin, adiponectin, β-casein, leptin, lysozyme, and α-lactalbumin. Oligosaccharides are contained in many of these compounds and provide the protection against infection that human infants need. The authors have dissected the structure and the activities of these vital substances. They confirmed the role of human milk in the protection of neonates against disease. Careful scrutiny of this work should serve to equip supporters of human milk with a vast armory in defense against those who attempt to claim that formula is competitive. As well as the glycoprotein protection against bacteria, HMGP provide protection for the intestinal mucosa. This function is vital to the infant born prematurely. The authors believe that there is a “prebiotic effect of HMGP that also contributes to the modulation of the intestinal response to injury and other types of intestinal inflammation conditions.” It is the perfect testimony needed to encourage neonatologists to provide human milk for all infants in the neonatal intensive care unit. Liu and Newburg
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further predict that biological testing with newer technologies for isolation, purification, and identification will uncover new sources of novel prophylactic and therapeutic agents that will inhibit diseases caused by a variety of pathogens.
Valuable data on milk production from the clinical laboratory of Kent et al.
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are also presented in this issue. Milk production was studied using longitudinal breastfeeding patterns. Discontinuing breastfeeding is most frequently blamed on perceived insufficient milk supply, the authors remind us. Participants were studied at home for at least two and as many as five 24-hour periods between 1 and 6 months postpartum. The subjects were combined from four separate longitudinal studies. The authors measured milk production by weighing the mother using the equipment designed and tested in Hartmann's laboratory
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years ago. Ingenious and accurate! They concluded that breastfeeding becomes more efficient in the first 3 months but that the intake by the infant remains constant. In the second 3 months the median and maximum breastmilk intakes were also constant. The duration of a feeding decreased over the 6 months, while the total 24-hour intake remained constant. Breastfeeding becomes more efficient, the authors pointed out, while intake remains constant. Clinicians need to know this and not assume lactation is failing. Mothers need to know it too and not become discouraged and stop too soon.
This journal continues to report on the value of the constituents of human milk from the bench laboratories as well as the analysis of the physiology of lactation in the clinical laboratories, but the business case for breastfeeding is equally important. Garvin et al.
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provide a detailed analysis of the cost saving provided when premature infants are fed human milk. Human milk saves the healthcare dollar. This issue of our journal provides a wealth of evidence for the reader in the battle to help mothers begin and continue to breastfeed their infants and to help scientists and clinicians defend their cause.
