The role of vitamin D in the cardiovascular system is complex because it regulates expression of genes involved in diverse metabolic processes. Although referred to as a vitamin, it is more accurately considered a steroid hormone, because it is produced endogenously in the presence of ultraviolet light. It occurs as a series of sequentially activated forms, here referred to as vitamin D-hormones. A little-known phenomenon, based on pre-clinical data, is that its biodistribution and potential effects on vascular disease likely depend on whether it is derived from diet or sunlight. Diet-derived vitamin D-hormones are carried in the blood, at least in part, in chylomicrons and lipoprotein particles, including low-density lipoprotein. Since low-density lipoprotein is known to accumulate in the artery wall and atherosclerotic plaque, diet-derived vitamin D-hormones may also collect there, and possibly promote the osteochondrogenic mineralization associated with plaque. Also, little known is the fact that the body stores vitamin D-hormones in adipose tissue with a half-life on the order of months, raising doubts about whether the use of the term "daily requirement" is appropriate. Cardiovascular effects of vitamin D-hormones are controversial, and risk appears to increase with both low and high blood levels. Since low serum vitamin D-hormone concentration is reportedly associated with increased cardiovascular and orthopedic risk, oral supplementation is widely used, often together with calcium supplements. However, meta-analyses show that oral vitamin D-hormone supplementation does not protect against cardiovascular events, findings that are also supported by a randomized controlled trial. These considerations suggest that prevalent recommendations for vitamin D-hormone supplementation for the purpose of cardiovascular protection should be carefully reconsidered.

中文翻译：

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类固醇激素维生素 D 对脉管系统的潜在影响。

维生素 D 在心血管系统中的作用很复杂，因为它调节参与多种代谢过程的基因的表达。虽然被称为维生素，但它更准确地被认为是类固醇激素，因为它是在紫外线存在下内源性产生的。它以一系列顺序激活的形式出现，这里称为维生素 D 激素。根据临床前数据，一个鲜为人知的现象是，它的生物分布和对血管疾病的潜在影响可能取决于它是来自饮食还是阳光。饮食衍生的维生素 D 激素在血液中携带，至少部分在乳糜微粒和脂蛋白颗粒中，包括低密度脂蛋白。由于已知低密度脂蛋白积聚在动脉壁和动脉粥样硬化斑块中，饮食衍生的维生素 D 激素也可能聚集在那里，并可能促进与斑块相关的骨软骨形成矿化。此外，鲜为人知的是，人体将维生素 D 激素储存在脂肪组织中，其半衰期约为数月，这引发了人们对“每日需求”一词是否合适的疑问。维生素 D 激素对心血管的影响是有争议的，并且风险似乎随着血液水平的低和高而增加。据报道，由于血清维生素 D 激素浓度低与心血管和骨科风险增加有关，因此口服补充剂被广泛使用，通常与钙补充剂一起使用。然而，荟萃分析表明，口服维生素 D 激素补充剂并不能预防心血管事件，随机对照试验也支持的研究结果。这些考虑表明，应仔细重新考虑为心血管保护目的而补充维生素 D 激素的普遍建议。