Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia,
School of Medicine, University of Adelaide, Adelaide, South Australia, Australia,
Ann Nutr Metab. 2020;76 Suppl 3:31-39. doi: 10.1159/000509901. Epub 2021 Jan 19.
Worldwide, around 15 million preterm babies are born annually, and despite intensive research, the specific mechanisms triggering preterm birth (PTB) remain unclear. Cost-effective primary prevention strategies to reduce PTB are required, and nutritional interventions offer a promising alternative. Nutrients contribute to a variety of mechanisms that are potentially important to preterm delivery, such as infection, inflammation, oxidative stress, and muscle contractility. Several observational studies have explored the association between dietary nutrients and/or dietary patterns and PTB, often with contrasting results. Randomized trial evidence on the effects of supplementation with zinc, multiple micronutrients (iron and folic acid), and vitamin D is promising; however, results are inconsistent, and many studies are not adequately powered for outcomes of PTB. Large-scale clinical trials with PTB as the primary outcome are needed before any firm conclusions can be drawn for these nutrients. The strongest evidence to date for a nutritional solution exists for omega-3 long-chain polyunsaturated fatty acids (LCPUFAs), key nutrients in fish. In 2018, a Cochrane Review (including 70 studies) showed that prenatal supplementation with omega-3 LCPUFAs reduced the risk of PTB and early PTB (EPTB) compared with no omega-3 supplementation. However, the largest trial of omega-3 supplementation in pregnancy, the Omega-3 to Reduce the Incidence of Prematurity (ORIP) trial (n = 5,544), showed no reduction in EPTB and a reduction in PTB only in a prespecified analysis of singleton pregnancies. Exploratory analyses from the ORIP trial found that women with low baseline total omega-3 status were at higher risk of EPTB, and that this risk was substantially reduced with omega-3 supplementation. In contrast, women with replete or high baseline total omega-3 status were already at low risk of EPTB and additional omega-3 supplementation increased the risk of EPTB compared to control. These findings suggest that determining an individual woman's PUFA status may be the most precise way to inform recommendations to reduce her risk of PTB.
全球每年约有 1500 万早产儿出生，尽管进行了深入研究，但触发早产（PTB）的确切机制仍不清楚。需要采取具有成本效益的初级预防策略来减少 PTB，而营养干预提供了一种有前途的替代方法。营养素有助于多种可能对早产分娩很重要的机制，例如感染、炎症、氧化应激和肌肉收缩性。一些观察性研究探讨了膳食营养素和/或膳食模式与 PTB 之间的关联，结果往往存在差异。关于补充锌、多种微量营养素（铁和叶酸）和维生素 D 对 PTB 的影响的随机试验证据很有希望；然而，结果不一致，许多研究对于 PTB 结局的研究力度不足。在得出这些营养素的任何确切结论之前，需要开展以 PTB 为主要结局的大规模临床试验。迄今为止，对于营养解决方案的最强证据存在于 omega-3 长链多不饱和脂肪酸（LCPUFAs）中，这些是鱼类中的关键营养素。2018 年，一项 Cochrane 综述（包括 70 项研究）表明，与没有 omega-3 补充相比，产前补充 omega-3 LCPUFAs 可降低 PTB 和早期 PTB（EPTB）的风险。然而，最大的 omega-3 补充妊娠试验，即减少早产发生率的 omega-3 试验（ORIP 试验，n = 5544），并没有显示 EPTB 减少，只有在对单胎妊娠的预设分析中才显示 PTB 减少。ORIP 试验的探索性分析发现，基线总 omega-3 状态较低的女性发生 EPTB 的风险较高，而 omega-3 补充可大大降低这种风险。相比之下，基线总 omega-3 状态充足或较高的女性已经处于 EPTB 的低风险中，与对照组相比，额外的 omega-3 补充会增加 EPTB 的风险。这些发现表明，确定个体女性的多不饱和脂肪酸状况可能是最精确的方法，可以为降低其 PTB 风险提供建议。
