Different doses of supplemental vitamin D maintain interleukin-5 without altering skeletal muscle strength: a randomized, double-blind, placebo-controlled study in vitamin D sufficient adults
Different doses of supplemental vitamin D maintain interleukin-5 without altering skeletal muscle strength: a randomized, double-blind, placebo-controlled study in vitamin D sufficient adults
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DOI：
10.1186/1743-7075-9-16
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发表时间：
2012-03-09
影响因子：
4.5
通讯作者：
Weaver, Lindell K.
中科院分区：
文献类型：
--
作者：
Barker, Tyler;Martins, Thomas B.;Weaver, Lindell K.
背景：补充维生素 D 可调节炎症细胞因子和骨骼肌功能，但结果并不一致。目前尚不清楚这些不一致是否取决于维生素 D 的补充剂量。因此，本研究的目的是确定不同剂量的补充维生素 D 对年轻人炎症细胞因子和肌肉力量的影响。方法：男性 (n = 15) 和女性 (n = 15) 在冬季每天接受安慰剂或维生素 D 补充剂（200 或 4000 IU），持续 28 天。在补充之前和期间进行血清 25-羟基维生素 D (25(OH)D)、细胞因子浓度和肌肉（腿部）力量测量。通过重复测量的双向（时间、治疗）方差分析 (ANOVA) 评估数据的统计显着性，然后使用 Tukey 诚实显着差异来测试多个成对比较。 结果：入组后，63% 的受试者维生素 D 充足（血清 25(OH)D = 30 ng/ml）。安慰剂组的血清 25(OH)D 和白细胞介素 (IL)-5 随着时间的推移而降低 (P < 0.05)。补充 200 IU 维生素 D 可维持血清 25(OH)D 浓度并增加 IL-5 (P < 0.05)。补充 4000 IU 维生素 D 增加 (P < 0.05) 血清 25(OH)D，但不改变 IL-5 浓度。尽管血清 25(OH)D 浓度与肌肉力量相关 (P < 0.05)，但补充维生素 D 不会改变肌肉力量。结论：在补充维生素 D 之前已摄入足够维生素 D 的年轻人中，我们得出结论，每日低剂量补充维生素 D 可防止血清 25(OH)D 和 IL-5 浓度下降，并且肌肉力量与每日高剂量补充维生素 D 引起的 25(OH)D 增加并不平行。 IL-5 可防止病毒和细菌感染，这些发现对于维生素 D 充足性介导免疫系统抵抗感染的能力具有广泛的生理重要性。
Background: Supplemental vitamin D modulates inflammatory cytokines and skeletal muscle function, but results are inconsistent. It is unknown if these inconsistencies are dependent on the supplemental dose of vitamin D. Therefore, the purpose of this study was to identify the influence of different doses of supplemental vitamin D on inflammatory cytokines and muscular strength in young adults.Methods: Men (n = 15) and women (n = 15) received a daily placebo or vitamin D supplement (200 or 4000 IU) for 28-d during the winter. Serum 25-hydroxyvitamin D (25(OH)D), cytokine concentrations and muscular (leg) strength measurements were performed prior to and during supplementation. Statistical significance of data were assessed with a two-way (time, treatment) analysis of variance (ANOVA) with repeated measures, followed by a Tukey's Honestly Significant Difference to test multiple pairwise comparisons.Results: Upon enrollment, 63% of the subjects were vitamin D sufficient (serum 25(OH)D = 30 ng/ml). Serum 25(OH)D and interleukin (IL)-5 decreased (P < 0.05) across time in the placebo group. Supplemental vitamin D at 200 IU maintained serum 25(OH)D concentrations and increased IL-5 (P < 0.05). Supplemental vitamin D at 4000 IU increased (P < 0.05) serum 25(OH)D without altering IL-5 concentrations. Although serum 25(OH)D concentrations correlated (P < 0.05) with muscle strength, muscle strength was not changed by supplemental vitamin D.Conclusion: In young adults who were vitamin D sufficient prior to supplementation, we conclude that a low-daily dose of supplemental vitamin D prevents serum 25(OH)D and IL-5 concentration decreases, and that muscular strength does not parallel the 25(OH)D increase induced by a high-daily dose of supplemental vitamin D. Considering that IL-5 protects against viruses and bacterial infections, these findings could have a broad physiological importance regarding the ability of vitamin D sufficiency to mediate the immune systems protection against infection.