Hamosh M
Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA.
Clin Perinatol. 1996 Jun;23(2):191-209.
Although the various aspects of digestion in the newborn have been studied for decades, we still lack quantitative information about the contribution of individual enzymes to the overall process. The information to date indicates that in spite of immaturity of many of the classical digestive mechanisms of the adult, the infant uses a number of compensatory systems to achieve adequate digestion of nutrients (Fig. 1). Thus, whereas in the infant gastric proteolysis is probably extremely limited, intestinal protein digestion is adequate. Although starch supplements are better tolerated in breast-fed infants, because of the compensation provided by human milk amylase, the infant is able to digest lactose and short-chain glucose polymers with endogenous brush border enzymes. Fat digestion is markedly aided by gastric lipase and, in breast-fed infants, the bile salt-dependent lipase of human milk. Thus, in the infant, gastric lipolysis is quantitatively much more significant than in adults. The absorption of human milk whey proteins (and probably also cow milk proteins) is probably associated more with the highly glycosylated form of these proteins than with immaturity of neonatal digestive enzymes.
尽管新生儿消化的各个方面已被研究了数十年，但我们仍缺乏关于个体酶对整个消化过程贡献的定量信息。迄今为止的信息表明，尽管许多成人经典消化机制不成熟，但婴儿会利用多种补偿系统来实现营养物质的充分消化（图1）。因此，尽管婴儿的胃蛋白水解作用可能极其有限，但肠道蛋白质消化却是充分的。由于母乳淀粉酶提供的补偿作用，母乳喂养的婴儿对淀粉补充剂的耐受性更好，婴儿能够利用内源性刷状缘酶消化乳糖和短链葡萄糖聚合物。胃脂肪酶以及母乳喂养婴儿体内母乳中的胆汁盐依赖性脂肪酶显著促进了脂肪消化。因此，在婴儿中，胃脂肪分解在数量上比成人更为显著。母乳乳清蛋白（可能还有牛奶蛋白）的吸收可能更多地与这些蛋白质的高度糖基化形式有关，而不是与新生儿消化酶的不成熟有关。
