The goal of nutrition of the preterm infant is to meet the growth rate of the healthy fetus of the same gestational age and to produce the same body composition of the healthy fetus in terms of organ growth, tissue components, and cell number and structure. Nutritional quantity and quality are fundamental for normal growth and development of preterm infants, including neurodevelopmental outcomes. Failure to provide the necessary amounts of all of the essential nutrients has produced not only growth failure, but also increased morbidity and less than optimal neurodevelopment. Growth velocities during the NICU hospitalization period for preterm infants exert a significant effect on neurodevelopmental and anthropometric outcomes. Despite the obvious need for optimal nutrition, growth failure is almost universal among preterm infants. There is every reason, therefore, to optimize nutrition of the preterm infant, in terms of total energy and protein, but also in terms of individual components such as amino acids, specific carbohydrates and lipids, and even oxygen. This review presents scientific rationale for nutrient requirements and practical guidelines and approaches to intravenous and enteral feeding for preterm infants. Intravenous feeding, including amino acids, should be started right after birth at rates that are appropriate for the gestational age of the infant. Enteral feeding should be started as soon as possible after birth, using mother's colostrum and milk as first choices. Enteral feeding should begin with trophic amounts and advanced as rapidly as tolerated, decreasing IV nutrition accordingly, while maintaining nutrient intakes at recommended rates. Feeding protocols are valuable for improving nutrition and related outcomes. Further research is needed to determine the optimal nutrition and rate of growth in preterm infants that will achieve optimal neurocognitive benefits while minimizing the longer-term risk of chronic diseases.
早产儿营养补给的目标是使早产儿能够达到同胎龄健康胎儿的正常生长速率，并且在器官生长、组织成分、以及细胞数量和结构方面也能达到健康胎儿水平。营养物质的数量与质量对于早产儿的正常生长发育、包括神经系统发育是至关重要的。基本营养素的供给不足不仅会造成生长受限，而且会增加病死率或影响神经发育结局。早产儿在NICU住院期间的生长速率在神经发育及整个人体发育的结局中发挥了重要作用。尽管对于最佳营养的需求非常明显，但早产儿生长落后的例子比比皆是。因此，根据总的能量及蛋白质需求以及个体成分如氨基酸、碳水化合物及脂肪，甚至细化到氧气的需求来优化早产儿的营养是非常必要的。该综述阐述了早产儿科学合理的营养需求、具有实用性的营养指南以及早产儿静脉营养、肠内营养的方法步骤。包括氨基酸在内的静脉营养，应该从一出生便按照相应胎龄所适合的速率开始补充。肠内营养则应在出生后尽早开始，首选母亲的初乳和牛奶。肠内营养应根据热能需要开始建立并在能耐受的范围内快速增加，保持营养摄入在推荐速率的同时相应地减少静脉营养摄入量。制定一个合理的喂养方案对于改善营养状况及相关的转归是重要的。什么是早产儿的最佳营养和生长速率尚有待于进一步的研究来确定，这种最佳营养不仅能使早产儿神经认知得到最充分的发育，同时还要最大程度地限制其远期发生慢性疾病的风险。