Ramel Sara E, Georgieff Michael K
Division of Neonatology, University of Minnesota Amplatz Children's Hospital, University of Minnesota School of Medicine, Minneapolis, Minn., USA.
World Rev Nutr Diet. 2014;110:190-200. doi: 10.1159/000358467. Epub 2014 Apr 11.
The brain is the most highly metabolic organ in the preterm neonate and consumes the greatest amount of nutrient resources for its function and growth. As preterm infants survive at greater rates, neurodevelopment has become the primary morbidity outcome of interest. While many factors influence neurodevelopmental outcomes in preterm infants, nutrition is of particular importance because the healthcare team has a great deal of control over its provision. Studies over the past 30 years have emphasized the negative neurodevelopmental consequences of poor nutrition and growth in the preterm infant. While all nutrients are important for brain development, certain ones including glucose, protein, fats (including long-chain polyunsaturated fatty acids), iron, zinc, copper, iodine, folate and choline have particularly large roles in the preterm infant. They affect major brain processes such as neurogenesis, neuronal differentiation, myelination and synaptogenesis, all of which are proceeding at a rapid pace between 22 and 42 weeks' post-conception. At the macronutrient level, weight gain, linear growth (independent of weight gain) and head circumference growth are markers of nutritional status. Each has been associated with long-term neurodevelopment. The relationship of micronutrients to neurodevelopment in preterm infants is understudied in spite of the large effect these nutrients have in other young populations. Nutrients do not function alone to stimulate brain development, but rather in concert with growth factors, which in turn are dependent on adequate nutrient status (e.g. protein, zinc) as well as on physiologic status. Non-nutritional factors such as infection, corticosteroids, and inflammation alter how nutrients are accreted and distributed, and also suppress growth factor synthesis. Thus, nutritional strategies to optimize brain growth and development include assessment of status at birth, aggressive provision of nutrients that are critical in this time period, control of non-nutritional factors that impede brain growth and repletion of nutrient deficits.
大脑是早产儿中代谢最活跃的器官，其功能和生长消耗的营养资源最多。随着早产儿存活率的提高，神经发育已成为主要关注的发病结局。虽然许多因素会影响早产儿的神经发育结局，但营养尤为重要，因为医疗团队在营养供应方面有很大的控制权。过去30年的研究强调了早产儿营养和生长不良对神经发育的负面影响。虽然所有营养素对大脑发育都很重要，但某些营养素，包括葡萄糖、蛋白质、脂肪（包括长链多不饱和脂肪酸）、铁、锌、铜、碘、叶酸和胆碱，在早产儿中发挥着特别重要的作用。它们影响神经发生、神经元分化、髓鞘形成和突触发生等主要脑过程，所有这些过程在孕后22至42周之间都在快速进行。在宏量营养素层面，体重增加、线性生长（独立于体重增加）和头围生长是营养状况的指标。每一项都与长期神经发育有关。尽管这些微量营养素在其他年轻人群中具有很大影响，但对早产儿微量营养素与神经发育之间关系的研究却很少。营养素并非单独发挥作用来刺激大脑发育，而是与生长因子协同作用，而生长因子又依赖于充足的营养状况（如蛋白质、锌）以及生理状况。感染、皮质类固醇和炎症等非营养因素会改变营养素的吸收和分布方式，还会抑制生长因子的合成。因此，优化大脑生长和发育的营养策略包括出生时的状况评估、积极提供这一时期至关重要的营养素、控制阻碍大脑生长的非营养因素以及补充营养缺乏。
