Effects of cholecalciferol supplementation on inflammatory markers and muscle damage indices of soccer players after a simulated soccer match

Objectives: Soccer-induced muscle damage and inflammation lead to a reduction in athletic performance. The aim of this study was to determine whether supplementation with cholecalciferol would reduce inflammation and muscle damage in soccer players after a simulated soccer match. Methods: Twenty-two soccer players (median age 27 y, interquartile range 5 y) were divided randomly into two groups, as follows: a cholecalciferol group (n = 11) and a placebo group (n = 11). Cholecalciferol supplements (50 000 IU/wk) or placebos were administered to the groups by an independent co-worker. After 8 wk, the athletes participated in a simulated soccer match, and perceived exertion and heart rates were measured during the trial. Blood samples were obtained presupplementation, postsupplementation, immediately after, and 2- and 24-h postexercise for measurement of lactate dehydrogenase, creatine phosphokinase, C-reactive protein (CRP), and interleukin (IL)-6. Results: The intervention group demonstrated a significant increase in serum 25-hydroxyvitamin D levels (53.93, 10.68 ng/mL, P < 0.0001), which is the best indicator of vitamin D levels in the body, with no change in the circulating markers of muscle damage and CRP (P > 0.05) but showed increased IL-6 (P = 0.034). In addition, the ratings of perceived exertion and heart rates were not altered by vitamin D compared with placebo ingestion (P = 0.155 versus P= 0.261; P = 0.600 versus P= 0.983). Conclusion: The study showed that 50 000 IU/wk of cholecalciferol supplementation for 8 wk increased the 25-hydroxyvitamin D levels, with no effect on muscle damage indices or CRP. However, The IL-6 concentration was generally higher in the intervention group. (C) 2018 Elsevier Inc. All rights reserved.