Human Milk: Composition, Clinical Benefits and Future Opportunities. Группа авторов
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      32Singhal A, Fewtrell M, Cole TJ, Lucas A: Low nutrient intake and early growth for later insulin resistance in adolescents born preterm. Lancet 2003; 361: 1089–1097.

      State of Breastfeeding in the World

      Donovan SM, German JB, Lönnerdal B, Lucas A (eds): Human Milk: Composition, Clinical Benefits and Future Opportunities. Nestlé Nutr Inst Workshop Ser, vol 90, pp 13–32, (DOI: 10.1159/000490322)

      Nestlé Nutrition Institute, Switzerland/S. Karger AG., Basel, © 2019

      ______________________

      Michael W. Woolridge

      Great Ormond Street Institute of Child Health, University College London, London, UK

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      Abstract

      Currently accepted “best practice” for managing breastfeeding effectively (WHO/UNICEF) is largely based on a historical view of how babies remove milk from the breast, which had persisted for several centuries. The collective wisdom was verified by imaging studies in the 1950s and 1980s, to reach a consensus view – clinical management principles, based on such research, have proved highly effective. Over the past decade, the mechanics of suckling, and how the baby removes milk from the breast, have been revisited, using modern imaging technology and by the application of engineering-based techniques, which seek to develop explanatory models of how suckling works. While the imaging studies have caused us to expand our view of the process, the engineering-based models have proved somewhat contradictory, tending to undermine the new consensus. Such models are complex, mathematically difficult to evaluate, and without simple lessons by which clinicians/practitioners can update their practice. This presentation will seek to demonstrate the current agreement between imaging studies, and elucidate recent engineering-based models of milk extraction, to achieve a fresh consensus – a “revised suckling physiology.” Certain limitations of the engineering-based models will be addressed, showing why they do not yet provide a definitive explanation of how babies remove milk from the breast. The encouraging news, however, is that current “best practice” for breastfeeding does not need to be updated; in fact, a new conclusion indicates that the guiding principles are even more relevant than before.

      © 2019 Nestlé Nutrition Institute, Switzerland/S. Karger AG, Basel

      Introduction

      For the best part of four centuries, the medical world was secure in its view of how babies fed and removed milk from the breast – the terms “sucking” and “suckling” became mutually replaceable, even though they describe separate processes. Two commonly accepted facts remain today: first, the baby generates high levels of suction pressure in the oral cavity, so that any object placed in a baby’s mouth (bottle-teat, finger, pacifier) cannot easily be removed. Second, the baby’s tongue moves in a wave-like manner, with positive pressure being exerted rhythmically by the dorsum of the tongue surface to the underside of the nipple/breast complex held in the baby’s mouth; this is regarded as a type feature of the baby, taken to indicate its neurodevelopmental maturity.

      What We Already Know

      Seven principal forces are present and active during breastfeeding, the first three affect the pressure of milk within the breast; all but one is active in milk transfer, while one plays a key role in retaining the breast within the baby’s mouth.

      (1) Atmospheric pressure is an important force in the process, although it is eclipsed by the positive pressure created by (2) the mother’s “let-down” or milk ejection reflex (MER). The MER creates phasic (intermittent) increases in positive pressure in the milk held within the breast, while also causing the milk ducts to dilate, so providing less resistance to the flow of milk to the nipple surface. Because breastfeeding is such a highly dynamic form of milk extraction, atmospheric pressure is more likely to play a role in milk extraction by breast pump (being less dynamic). These two forces constitute one side of an active pressure gradient.

      A less obvious process creating positive pressure in the breast is (3) the compressive pressure of the baby’s lips against the СКАЧАТЬ