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Effects of vitamin D3 supplementation on cardiac, muscle, and immune responses after a marathon race: a single-blind, placebo-controlled trial.

  • 2026-04-12
  • Journal of the International Society of Sports Nutrition 23(1)
    • Pei-Wei Weng
    • Josephine Diony Nanda
    • Yu-Hsiu Chien
    • Chiou-Feng Lin
    • Shih-Chung Cheng
    • Ming-Ta Yang

Study Design

Type
Randomized Controlled Trial (RCT)
Population
21 amateur runners
Methods
Twenty-one amateur runners were allocated to either a vitamin D3 supplementation group (receiving vitamin D3 for 8 weeks) or a placebo group. All participants completed an official full marathon (42.195 km). Blood biomarkers were measured from 24 h before to 24 h after the race.
Duration
8 weeks

Background

Strenuous endurance exercise imposes substantial physiological stress on the cardiovascular system and has been associated with transient elevations in cardiac biomarkers. Vitamin D₃ has been suggested to influence oxidative stress and immune responses. In this study, we investigated the effects of vitamin D₃ supplementation on biomarkers of cardiac, muscle, and immune responses following a marathon race.

Methods

Twenty-one amateur runners were allocated to either a vitamin D₃ supplementation group (receiving vitamin D₃ for 8 weeks) or a placebo group. All participants completed an official full marathon (42.195 km). Blood biomarkers were measured from 24 h before to 24 h after the race.

Results

Post-race increases in markers of muscle damage and cardiac stress were observed. Vitamin D₃ supplementation was associated with attenuated elevations in selected biomarkers demonstrating significant interaction effects. Compared with the placebo group, the vitamin D₃ group demonstrated attenuation of protein carbonyls (PC), the only oxidative stress marker showing a significant Group × Time interaction. No significant interaction effects were observed for thiobarbituric acid reactive substances (TBARS) or antioxidant enzymes. Both groups showed post-race increases in white blood cell counts, particularly neutrophils, whereas lymphocyte counts significantly decreased at 0.5 h and 2 h post-race. Immunoprofiling revealed time-dependent alterations in selected immune cell subsets, although no significant interaction effects were detected. Descriptive differences in recovery patterns were observed between groups, and exploratory correlation analyses suggested time-specific associations between immune cell subsets and biochemical markers during recovery.

Conclusion

Vitamin D₃ supplementation may attenuate PC responses and was associated with lower creatine kinase (CK) and creatine kinase-MB (CK-MB) levels at 24 h post-race following marathon running. Immune alterations were time-dependent, with descriptive differences in recovery patterns between groups.

Research Insights

  • Vitamin D→Reduced Antioxidant Enzyme Level

    No significant interaction effects were observed for thiobarbituric acid reactive substances (TBARS) or antioxidant enzymes.

    Effect
    Neutral
    Effect size
    Small
  • Vitamin D→Reduced Creatine Kinase Level

    Vitamin D₃ supplementation may attenuate PC responses and was associated with lower creatine kinase (CK) and creatine kinase-MB (CK-MB) levels at 24 h post-race following marathon running.

    Effect
    Neutral
    Effect size
    Small
  • Vitamin D→Reduced Creatine Kinase MB

    Vitamin D₃ supplementation may attenuate PC responses and was associated with lower creatine kinase (CK) and creatine kinase-MB (CK-MB) levels at 24 h post-race following marathon running.

    Effect
    Neutral
    Effect size
    Small
  • Vitamin D→Reduced Lymphocyte Count

    Both groups showed post-race increases in white blood cell counts, particularly neutrophils, whereas lymphocyte counts significantly decreased at 0.5 h and 2 h post-race.

    Effect
    Neutral
    Effect size
    Small
  • Vitamin D→Reduced Neutrophil Count

    Both groups showed post-race increases in white blood cell counts, particularly neutrophils, whereas lymphocyte counts significantly decreased at 0.5 h and 2 h post-race.

    Effect
    Neutral
    Effect size
    Small
  • Vitamin D→Reduced Protein Carbonyl Level

    Compared with the placebo group, the vitamin D₃ group demonstrated attenuation of protein carbonyls (PC), the only oxidative stress marker showing a significant Group × Time interaction.

    Effect
    Beneficial
    Effect size
    Small
  • Vitamin D→Reduced Thiobarbituric Acid-Reactive Substance Levels

    No significant interaction effects were observed for thiobarbituric acid reactive substances (TBARS) or antioxidant enzymes.

    Effect
    Neutral
    Effect size
    Small
  • Vitamin D→Reduced White Blood Cell Count

    Both groups showed post-race increases in white blood cell counts, particularly neutrophils, whereas lymphocyte counts significantly decreased at 0.5 h and 2 h post-race.

    Effect
    Neutral
    Effect size
    Small
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