Medical School, Royal Perth Hospital Unit, University of Western Australia, Perth, Western Australia, Australia.
School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
Am J Clin Nutr. 2018 Apr 1;107(4):504-522. doi: 10.1093/ajcn/nqx046.
Dietary nitrate is an important source of nitric oxide (NO), a molecule critical for cardiovascular health. Nitrate is sequentially reduced to NO through an enterosalivary nitrate-nitrite-NO pathway that involves the oral microbiome. This pathway is considered an important adjunct pathway to the classical l-arginine-NO synthase pathway.
The objective of this study was to systematically assess the evidence for dietary nitrate intake and improved cardiovascular health from both human and animal studies.
A systematic literature search was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines by using key search terms in Medline and EMBASE databases and defined inclusion and exclusion criteria.
Thirty-seven articles on humans and 14 articles on animals were included from 12,541 screened references. Data on the effects of dietary nitrate on blood pressure, endothelial function, ischemic reperfusion injury, arterial stiffness, platelet function, and cerebral blood flow in both human and animal models were identified. Beneficial effects of nitrate on vascular health have predominantly been observed in healthy human populations, whereas effects in populations at risk of cardiovascular disease are less clear. Few studies have investigated the long-term effects of dietary nitrate on cardiovascular disease clinical endpoints. In animal studies, there is evidence that nitrate improves blood pressure and endothelial function, particularly in animal models with reduced NO bioavailability. Nitrate dose seems to be a critical factor because there is evidence of cross-talk between the 2 pathways of NO production.
Evidence for a beneficial effect in humans at risk of cardiovascular disease is limited. Furthermore, there is a need to investigate the long-term effects of dietary nitrate on cardiovascular disease clinical endpoints. Further animal studies are required to elucidate the mechanisms behind the observed effects.
膳食硝酸盐是一氧化氮（NO）的重要来源，NO 是心血管健康的关键分子。硝酸盐通过涉及口腔微生物组的肠唾液硝酸盐-亚硝酸盐-NO 途径依次还原为 NO。该途径被认为是经典 l-精氨酸-NO 合酶途径的重要辅助途径。
本研究旨在系统评估来自人体和动物研究的膳食硝酸盐摄入与改善心血管健康的证据。
根据 PRISMA（系统评价和荟萃分析的首选报告项目）指南，使用 Medline 和 EMBASE 数据库中的关键搜索词进行系统文献检索，并定义了纳入和排除标准。
从 12541 篇筛选出的参考文献中，共纳入了 37 篇关于人类的文章和 14 篇关于动物的文章。确定了膳食硝酸盐对人类和动物模型中血压、内皮功能、缺血再灌注损伤、动脉僵硬、血小板功能和脑血流的影响的数据。硝酸盐对血管健康的有益影响主要在健康人群中观察到，而在心血管疾病风险人群中的影响则不太清楚。很少有研究调查膳食硝酸盐对心血管疾病临床终点的长期影响。在动物研究中，有证据表明硝酸盐可改善血压和内皮功能，尤其是在 NO 生物利用度降低的动物模型中。硝酸盐剂量似乎是一个关键因素，因为存在两种 NO 生成途径之间相互作用的证据。
在有心血管疾病风险的人群中，证据有限。此外，有必要调查膳食硝酸盐对心血管疾病临床终点的长期影响。需要进一步的动物研究来阐明观察到的影响背后的机制。
