Stanhewicz Anna E, Kenney W Larry
A.E. Stanhewicz and W.L. Kenney are with the Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, USA.
Nutr Rev. 2017 Jan;75(1):61-70. doi: 10.1093/nutrit/nuw053.
Folic acid is a member of the B-vitamin family and is essential for amino acid metabolism. Adequate intake of folic acid is vital for metabolism, cellular homeostasis, and DNA synthesis. Since the initial discovery of folic acid in the 1940s, folate deficiency has been implicated in numerous disease states, primarily those associated with neural tube defects in utero and neurological degeneration later in life. However, in the past decade, epidemiological studies have identified an inverse relation between both folic acid intake and blood folate concentration and cardiovascular health. This association inspired a number of clinical studies that suggested that folic acid supplementation could reverse endothelial dysfunction in patients with cardiovascular disease (CVD). Recently, in vitro and in vivo studies have begun to elucidate the mechanism(s) through which folic acid improves vascular endothelial function. These studies, which are the focus of this review, suggest that folic acid and its active metabolite 5-methyl tetrahydrofolate improve nitric oxide (NO) bioavailability by increasing endothelial NO synthase coupling and NO production as well as by directly scavenging superoxide radicals. By improving NO bioavailability, folic acid may protect or improve endothelial function, thereby preventing or reversing the progression of CVD in those with overt disease or elevated CVD risk.
叶酸是B族维生素家族的一员，对氨基酸代谢至关重要。充足摄入叶酸对新陈代谢、细胞内稳态及DNA合成至关重要。自20世纪40年代首次发现叶酸以来，叶酸缺乏已被认为与多种疾病状态有关，主要是与子宫内神经管缺陷及晚年神经退行性变相关的疾病。然而，在过去十年中，流行病学研究发现叶酸摄入量及血液叶酸浓度与心血管健康之间存在负相关关系。这种关联引发了多项临床研究，这些研究表明补充叶酸可逆转心血管疾病（CVD）患者的内皮功能障碍。最近，体外和体内研究已开始阐明叶酸改善血管内皮功能的机制。这些研究是本综述的重点，表明叶酸及其活性代谢物5-甲基四氢叶酸可通过增加内皮型一氧化氮合酶偶联及一氧化氮生成以及直接清除超氧阴离子自由基来提高一氧化氮（NO）的生物利用度。通过提高NO生物利用度，叶酸可能保护或改善内皮功能，从而预防或逆转患有明显疾病或心血管疾病风险升高者的心血管疾病进展。
