The Nutrition Doctor, Skokie, Illinois, USA.
Nutrition. 2013 Jan;29(1):37-41. doi: 10.1016/j.nut.2012.05.010. Epub 2012 Oct 22.
Vitamin D deficiency, diagnosed when the serum 25-hydroxyvitamin D (25-OHD(3)) concentration is less than 20 ng/mL, has joined vitamin A deficiency as two of the most common nutrition-responsive medical conditions worldwide. There have been more scientific articles published about vitamin D in the 21st century than about any other vitamin, reflecting the massive expansion of the field of vitamin D research. Adequate vitamin D status has been linked to decreased risks of developing specific cancers, including cancers of the esophagus, stomach, colon, rectum, gallbladder, pancreas, lung, breast, uterus, ovary, prostate, urinary bladder, kidney, skin, thyroid, and hematopoietic system (e.g., Hodgkin's lymphoma, non-Hodgkin's lymphoma, multiple myeloma); bacterial infections; rheumatoid arthritis; Crohn's disease; periodontal disease; multiple sclerosis; asthma; type 2 diabetes; cardiovascular disease; stroke; peripheral artery disease; hypertension; chronic kidney disease; muscle weakness; cognitive impairment; Alzheimer's disease; clinical depression; and premature death. On the other hand, inadequate vitamin D status during human pregnancy may be associated with increased risk for the development of type 1 diabetes in the offspring. However, this point of view may be excessively optimistic. There also is evidence that despite the current heavy reliance on serum 25-OHD(3) concentration for the diagnosis of an individual's vitamin D status, local tissue vitamin D intoxication may be present in individuals with much lower serum 25-OHD(3) concentrations than are currently appreciated. Only rarely are the symptoms of local tissue vitamin D intoxication associated with vitamin D status or intake. An individual's serum 25-OHD(3) concentration may appear to be "low" for reasons totally independent of sunlight exposure or vitamin D intake. Serum 25-OHD(3) concentration is only poorly responsive to increases in vitamin D intake, and the prolonged routine consumption of thousands of international units of vitamin D may interfere with the regulation of phosphate homeostasis by fibroblast growth factor-23 (FGF23) and the Klotho gene product, with consequences that are detrimental to human health. In light of these counterbalancing observations, curbing excessive enthusiasm for universally increasing vitamin D intake recommendations may be in order.
维生素 D 缺乏症是指血清 25-羟维生素 D（25-OHD(3)）浓度低于 20ng/ml，现已与维生素 A 缺乏症一起成为全球最常见的两种营养相关医学病症。在 21 世纪，有关维生素 D 的科学文章比任何其他维生素都多，这反映了维生素 D 研究领域的大规模扩展。适当的维生素 D 状态与降低特定癌症的风险有关，包括食管癌、胃癌、结肠癌、直肠癌、胆囊癌、胰腺癌、肺癌、乳腺癌、子宫癌、卵巢癌、前列腺癌、膀胱癌、肾癌、皮肤癌、甲状腺癌和造血系统（如霍奇金淋巴瘤、非霍奇金淋巴瘤、多发性骨髓瘤）、细菌感染、类风湿性关节炎、克罗恩病、牙周病、多发性硬化症、哮喘、2 型糖尿病、心血管疾病、中风、外周动脉疾病、高血压、慢性肾脏病、肌肉无力、认知障碍、阿尔茨海默病、临床抑郁症和过早死亡。另一方面，孕妇维生素 D 不足可能与后代 1 型糖尿病的发病风险增加有关。然而，这种观点可能过于乐观。也有证据表明，尽管目前主要依赖血清 25-OHD(3)浓度来诊断个体的维生素 D 状态，但与目前认识到的相比，个体的血清 25-OHD(3)浓度低得多时，局部组织维生素 D 中毒可能存在。只有极少数情况下，局部组织维生素 D 中毒的症状与维生素 D 状态或摄入有关。个体的血清 25-OHD(3)浓度可能由于与阳光暴露或维生素 D 摄入完全无关的原因而显得“低”。血清 25-OHD(3)浓度对维生素 D 摄入的增加反应很差，长期常规摄入数千国际单位的维生素 D 可能会干扰成纤维细胞生长因子 23（FGF23）和 Klotho 基因产物对磷酸盐稳态的调节，对人类健康造成不利后果。鉴于这些相互矛盾的观察结果，控制对普遍增加维生素 D 摄入建议的过度热情可能是必要的。
