Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Rama 6 Rd, Rajthevi, Bangkok 10400, Thailand.
Nutr J. 2013 Apr 4;12:39. doi: 10.1186/1475-2891-12-39.
It is not known whether genetic variation in the vitamin D binding protein (DBP) influences 25-hydroxyvitamin D levels [25(OH)D] after vitamin D supplementation. We aimed to investigate the changes of total 25(OH)D, 25(OH)D₃ and 25(OH)D₂ in a Thai cohort, according to type of vitamin D supplement (vitamin D₃ or D₂) and DBP genotype, after receiving vitamin D₃ or D₂ for 3 months.
Thirty-nine healthy subjects completed the study. All subjects received 400 IU of either vitamin D₃ or D₂, plus a calcium supplement, every day for 3 months. Total serum 25(OH)D, 25(OH)D₃ and 25(OH)D₂ were measured by LC-MS/MS. Individual genotyping of rs4588 in the DBP gene was performed using real-time PCR.
Vitamin D₃ supplementation of 400 IU/d increased 25(OH)D₃ significantly (+16.2 ± 4.2 nmol/L, p <0.001). Vitamin D₂ (400 IU/d) caused increased 25(OH)D₂ levels (+22.0 ± 2.11 nmol/L, p <0.001), together with a decrease of 25(OH)D₃ (-14.2 ± 2.0 nmol/L, p <0.001). At 3 month, subjects in vitamin D3 group tended to have higher total 25(OH)D levels than those in vitamin D₂ (67.8 ± 3.9 vs. 61.0 ± 3.0 nmol/L; p = 0.08). Subjects were then classified into two subgroups: homozygous for the DBP rs4588 C allele (CC), and the rest (CA or AA). With D₃ supplementation, subjects with CA or AA alleles had significantly less increase in 25(OH)D₃ and total 25(OH)D when compared with those with the CC allele. However, no difference was found when the supplement was vitamin D₂.
Genetic variation in DBP (rs4588 SNP) influences responsiveness to vitamin D₃ but not vitamin D₂.
维生素 D 结合蛋白（DBP）的遗传变异是否会影响维生素 D 补充后的 25-羟维生素 D 水平[25（OH）D]尚不清楚。我们旨在研究在接受 3 个月的维生素 D₃ 或 D₂补充后，根据维生素 D 补充剂（D₃ 或 D₂）的类型和 DBP 基因型，泰国队列中总 25（OH）D、25（OH）D₃ 和 25（OH）D₂ 的变化。
39 名健康受试者完成了这项研究。所有受试者每天接受 400IU 的维生素 D₃ 或 D₂，外加钙补充剂，持续 3 个月。采用 LC-MS/MS 测定血清总 25（OH）D、25（OH）D₃ 和 25（OH）D₂。使用实时 PCR 对 DBP 基因中的 rs4588 进行个体基因分型。
每天补充 400IU 的维生素 D₃可显著增加 25（OH）D₃（+16.2±4.2nmol/L，p<0.001）。维生素 D₂（400IU/d）可增加 25（OH）D₂ 水平（+22.0±2.11nmol/L，p<0.001），同时降低 25（OH）D₃（-14.2±2.0nmol/L，p<0.001）。在 3 个月时，维生素 D₃ 组的受试者总 25（OH）D 水平倾向于高于维生素 D₂ 组（67.8±3.9 vs. 61.0±3.0nmol/L；p=0.08）。然后将受试者分为两个亚组：DBP rs4588 C 等位基因（CC）纯合子和其余（CA 或 AA）。在补充 D₃ 时，与 CC 等位基因相比，CA 或 AA 等位基因的受试者 25（OH）D₃ 和总 25（OH）D 的增加明显减少。然而，当补充剂是维生素 D₂ 时，没有发现差异。
DBP（rs4588 SNP）的遗传变异影响对维生素 D₃ 的反应性，但不影响对维生素 D₂ 的反应性。
