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Differential and Dose-Dependent Redistribution of Vitamin D Metabolites After Acute High-Intensity Exercise in Mixed Martial Arts Athletes and Untrained Men: Pilot Study.

  • 2026-03-26
  • Nutrients 18(7)
    • Katarzyna Patrycja Dzik
    • Katarzyna Jagłowska
    • Miłosz Palicki
    • Sylwester Kujach
    • Piotr Sawicki
    • Konrad Kowalski
    • Jan Jacek Kaczor

Study Design

Type
Randomized Controlled Trial (RCT)
Population
34 healthy young men, comprising 22 mixed martial arts (MMA) athletes and 12 untrained controls
Methods
MMA athletes received either 3500 or 6000 IU/day of vitamin D3 for four weeks, while untrained participants received 3500 IU/day or a placebo. Before and after the intervention, participants performed a supramaximal anaerobic exercise protocol (3 × 30 s Wingate tests). Blood samples were collected at rest and 30 min and 24 h post-exercise.
Blinding
Single-blind
Duration
four weeks
  • Rigorous Journal
Background/Objectives: Acute high-intensity exercise may transiently alter circulating vitamin D metabolites. However, the effects of training status, supplementation dose, and vitamin D-binding protein (VDBP) on the exercise-induced redistribution and bioavailability of vitamin D remain unclear. This pilot study examined whether training status and vitamin D3 supplementation dose modulate vitamin D status, anaerobic performance, and acute post-exercise changes in vitamin D metabolites and VDBP. Methods: Thirty-four healthy young men participated, comprising 22 mixed martial arts (MMA) athletes and 12 untrained controls. MMA athletes received either 3500 or 6000 IU/day of vitamin D3 for four weeks, while untrained participants received 3500 IU/day or a placebo. Before and after the intervention, participants performed a supramaximal anaerobic exercise protocol (3 × 30 s Wingate tests). Blood samples were collected at rest and 30 min and 24 h post-exercise to assess vitamin D metabolites, VDBP, bioavailable and free 25(OH)D3, interleukin-6, and lactate. Results: Supplementation with 3500 IU/day significantly increased serum 25(OH)D3 in untrained men (p = 0.003) but not in MMA athletes. In contrast, 6000 IU/day increased 25(OH)D3 in MMA athletes to a sufficient concentration (p = 0.001) and improved maximal power (+7.5%), mean power (+4.9%), and total work (+5.0%). Acute exercise increased circulating vitamin D metabolites in trained athletes but reduced them in untrained men supplemented with vitamin D. Conclusions: The efficacy of vitamin D3 supplementation and the acute exercise-induced vitamin D responses appear to be training-dependent. A daily dose of 6000 IU is more effective in achieving vitamin D sufficiency and performance benefits in MMA athletes, whereas 3500 IU is sufficient for untrained men.

Research Insights

  • Vitamin D3→Improved Maximal Power

    In contrast, 6000 IU/day increased 25(OH)D3 in MMA athletes to a sufficient concentration (p = 0.001) and improved maximal power (+7.5%), mean power (+4.9%), and total work (+5.0%).

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    6000 IU/day
  • Vitamin D3→Improved Mean Power

    In contrast, 6000 IU/day increased 25(OH)D3 in MMA athletes to a sufficient concentration (p = 0.001) and improved mean power (+4.9%).

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    6000 IU/day
  • Vitamin D3→Improved Work Capacity

    In contrast, 6000 IU/day increased 25(OH)D3 in MMA athletes to a sufficient concentration (p = 0.001) and improved total work (+5.0%).

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    6000 IU/day
  • Vitamin D3→Increased Vitamin D Level

    Supplementation with 3500 IU/day significantly increased serum 25(OH)D3 in untrained men (p = 0.003) but not in MMA athletes.

    Effect
    Beneficial
    Effect size
    Large
    Dose
    6000 IU/day
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