Department of Kinesiology, College of Health Sciences, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA 71209, USA.
Department of Taekwondo, College of Physical Education, Kyung Hee University, 1732 Deokyoungdaero, Giheung-gu, Yongin-si, Gyeonggi-do 17014, Korea.
Int J Environ Res Public Health. 2018 Sep 14;15(9):2003. doi: 10.3390/ijerph15092003.
Vitamin D insufficiency may be associated with increased risk of upper respiratory tract infection (URTI) in athletes. This study examined the effects of vitamin D₃ supplementation on salivary immune functions and symptoms of URTI in vitamin D-insufficient taekwondo athletes. Twenty-five male taekwondo athletes, aged 19⁻22 years with vitamin D insufficiency [serum 25-hydroxyvitamin-D concentrations (25(OH)D, 31.3 ± 1.39 nmol/L)], participated in this study. They were randomized to receive 5000 IU/day of vitamin D₃ ( = 13) or placebo capsule ( = 12) during 4 weeks of winter training. Blood samples were collected two times (pre- and post-tests) for analyzing serum 25(OH)D concentration while salivary samples were obtained three times (pre-, mid-, and post-tests) for secretory immunoglobulin A (SIgA) and lactoferrin analyses. The symptoms of URTI were reported daily during the intervention. Serum 25(OH)D concentration significantly increased by 255.6% in the vitamin D group, whereas in the placebo group it did not change ( < 0.001). While the significant increase in SIgA was observed in both groups ( < 0.001), elevated salivary lactoferrin level in response to winter training was found only in the placebo group ( = 0.011). The change in serum 25(OH)D concentration was negatively associated with total URTI symptoms ( = -0.435, = 0.015). Vitamin D₃ supplementation may be effective in reducing the symptoms of URTI during winter training in vitamin D-insufficient taekwondo athletes.
维生素 D 不足可能与运动员上呼吸道感染 (URTI) 风险增加有关。本研究探讨了维生素 D₃ 补充对维生素 D 不足的跆拳道运动员唾液免疫功能和 URTI 症状的影响。25 名年龄在 19-22 岁、维生素 D 不足[血清 25-羟维生素 D 浓度 (25(OH)D，31.3 ± 1.39 nmol/L)]的男性跆拳道运动员参与了这项研究。他们被随机分为在冬季训练的 4 周内每天服用 5000 IU 维生素 D₃( = 13)或安慰剂胶囊( = 12)。在两次(预测试和后测试)采集血液样本以分析血清 25(OH)D 浓度，同时在三次(预测试、中期测试和后测试)采集唾液样本以分析分泌型免疫球蛋白 A (SIgA)和乳铁蛋白。在干预期间，每日报告 URTI 症状。维生素 D 组血清 25(OH)D 浓度显著增加 255.6%，而安慰剂组则没有变化( < 0.001)。虽然两组的 SIgA 均显著增加( < 0.001)，但仅在安慰剂组观察到冬季训练时唾液乳铁蛋白水平升高( = 0.011)。血清 25(OH)D 浓度的变化与 URTI 总症状呈负相关( = -0.435， = 0.015)。维生素 D₃ 补充可能有助于减少维生素 D 不足的跆拳道运动员在冬季训练期间 URTI 的症状。
