Cashman Kevin D, Kinsella Michael, Walton Janette, Flynn Albert, Hayes Aoife, Lucey Alice J, Seamans Kelly M, Kiely Mairead
School of Food and Nutritional Sciences and Department of Medicine, University College Cork, Cork, Ireland
School of Food and Nutritional Sciences and.
J Nutr. 2014 Jul;144(7):1050-7. doi: 10.3945/jn.114.192419. Epub 2014 May 14.
Fundamental knowledge gaps in relation to the 3 epimer of 25-hydroxycholecalciferol [3-epi-25(OH)D₃] limit our understanding of its relevance for vitamin D nutrition and health. The aims of this study were to characterize the 3-epi-25(OH)D₃ concentrations in a nationally representative sample of adults and explore its determinants. We also used data from a recent randomized controlled trial (RCT) of supplemental cholecalciferol (vitamin D₃) conducted in winter in older adults to directly test the impact of changes in vitamin D status on serum 3-epi-25(OH)D3 concentrations. Serum 25-hydroxycholecalciferol [25(OH)D₃] and 3-epi-25(OH)D₃ concentrations (via LC-tandem mass spectrometry) from our vitamin D₃ RCT in adults (aged ≥50 y) and data on dietary, lifestyle, and biochemical characteristics of participants of the recent National Adult Nutrition Survey in Ireland (aged 18-84 y; n = 1122) were used in the present work. In the subsample of participants who had serum 3-epi-25(OH)D₃ concentrations greater than the limit of quantification (n = 1082; 96.4%), the mean, 10th, 50th (median), and 90th percentile concentrations were 2.50, 1.05, 2.18, and 4.30 nmol/L, respectively, whereas the maximum 3-epi-25(OH)D₃ concentration was 15.0 nmol/L. A regression model [explaining 29.9% of the variability in serum 3-epi-25(OH)D₃] showed that age >50 y, vitamin D supplement use, dietary vitamin D, meat intake, season of blood sampling, and sun exposure habits were significant positive determinants, whereas increasing waist circumference and serum 25-hydroxyergocalciferol concentration were significant negative determinants. The RCT data showed that mean serum 25(OH)D₃ and 3-epi-25(OH)D₃ concentrations increased (49.3% and 42.1%, respectively) and decreased (-28.0% and -29.1%, respectively) significantly (P < 0.0001) with vitamin D₃ (20 μg/d) and placebo supplementation, respectively, over 15 wk of winter. In conclusion, we provide data on serum 3-epi-25(OH)D₃ in a nationally representative sample of adults. Our combined observational and RCT data might suggest that both dietary supply and dermal synthesis of vitamin D₃ contribute to serum 3-epi-25(OH)D₃ concentration.
与25-羟基胆钙化醇的3-表异构体[3-表-25(OH)D₃]相关的基础知识空白限制了我们对其在维生素D营养与健康方面相关性的理解。本研究的目的是对全国代表性成年人样本中的3-表-25(OH)D₃浓度进行特征描述，并探究其决定因素。我们还利用了近期在冬季对老年人进行的补充胆钙化醇（维生素D₃）随机对照试验（RCT）的数据，以直接测试维生素D状态变化对血清3-表-25(OH)D₃浓度的影响。本研究使用了我们在成年人（年龄≥50岁）中进行的维生素D₃ RCT的血清25-羟基胆钙化醇[25(OH)D₃]和3-表-25(OH)D₃浓度（通过液相色谱-串联质谱法测定），以及爱尔兰近期全国成人营养调查参与者（年龄18 - 84岁；n = 1122）的饮食、生活方式和生化特征数据。在血清3-表-25(OH)D₃浓度高于定量限的参与者子样本中（n = 1082；96.4%），平均、第10、第50（中位数）和第90百分位数浓度分别为2.50、1.05、2.18和4.30 nmol/L，而3-表-25(OH)D₃的最高浓度为15.0 nmol/L。一个回归模型[解释了血清3-表-25(OH)D₃变异性的29.9%]显示，年龄>50岁、使用维生素D补充剂、饮食中的维生素D、肉类摄入量、采血季节和日晒习惯是显著的正决定因素，而腰围增加和血清25-羟基麦角钙化醇浓度是显著的负决定因素。RCT数据显示，在冬季的15周内，分别补充维生素D₃（20μg/d）和安慰剂后，血清25(OH)D₃和3-表-25(OH)D₃的平均浓度显著增加（分别为49.3%和42.1%）和降低（分别为-28.0%和-29.1%）（P < 0.0001）。总之，我们提供了全国代表性成年人样本中血清3-表-25(OH)D₃的数据。我们综合的观察性数据和RCT数据可能表明，维生素D₃的饮食供应和皮肤合成均对血清3-表-25(OH)D₃浓度有贡献。
