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Research article
Changes in Serum 25 Hydroxyvitamin D Concentrations in Male University Long-Distance Runners Following Vitamin D3 Supplementation During Winter: A Randomized Controlled Trial
Toraishi Mami
Teikyo University: Teikyo Daigaku
Corresponding Author
ORCiD: https://orcid.org/0000-0002-1514-4088
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background
Vitamin D insufficiency and deficiency remain a global problem, even among athletes. In this study, we evaluated the serum 25 hydroxyvitamin D [25 (OH) D] concentrations of male long-distance runners during winter and the effect of short-term vitamin D3 supplementation to elucidate their dietary vitamin D requirements.
Methods
Using double-blind randomization, 34 athletes on the “Ekiden” (long-distance road race) team at University A were divided into a vitamin D group (n = 17, 25 μg/day of vitamin D3 intake) and a placebo group (n = 17, placebo tablet intake). Both groups ate normal meals with either the supplement or placebo included, and all subjects underwent a 31-day dietary survey. The pre- and post-intervention body composition and blood test were measured and compared.
Results
Prior to intervention, the vitamin D intake amount was 16.7 ± 7.2 μg/day, but the serum 25 (OH) D concentration was 28.9 ± 5.7 ng/mL, and 22 (65%) of the 34 subjects had insufficient vitamin D (<30 ng/mL). During the intervention period, the mean amount of vitamin D intake was 40.0 ± 5.5 μg/day in the vitamin D group and 13.4 ± 7.7 μg/day in the placebo group. Serum 25 (OH) D concentrations increased from 30.7 ± 6.7 ng/mL to 35.4 ± 6.6 ng/mL in the vitamin D group and from 27.1 ± 3.9 ng/mL to 28.5 ± 4.4 ng/mL in the placebo group, respectively (p < 0.001, p < 0.01). After intervention, the serum 25 (OH) D concentration in the vitamin D group was significantly higher (p < 0.001). Additionally, the rate of vitamin D sufficiency was 82% in the vitamin D group and 43% in the placebo group, indicating a significant difference (p < 0.01).
Conclusions
Our results demonstrate that post-intervention serum 25 (OH) D concentration was related to both mean vitamin D intake amount during the intervention period and pre-intervention serum 25 (OH) D concentration. However, to better quantify the required amount of vitamin D, further study of the effect of vitamin D supplementation on bone health is needed.
Keywords
Long-distance runner, 25 hydroxyvitamin D, vitamin D3 supplement, winter
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This is a preprint. It has not completed peer review.
Research article
Changes in Serum 25 Hydroxyvitamin D Concentrations in Male University Long-Distance Runners Following Vitamin D3 Supplementation During Winter: A Randomized Controlled Trial
Toraishi Mami
Teikyo University: Teikyo Daigaku
Corresponding Author
ORCiD: https://orcid.org/0000-0002-1514-4088
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 07 Jan, 2021
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Sports Medicine and Kinesiology
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background
Vitamin D insufficiency and deficiency remain a global problem, even among athletes. In this study, we evaluated the serum 25 hydroxyvitamin D [25 (OH) D] concentrations of male long-distance runners during winter and the effect of short-term vitamin D3 supplementation to elucidate their dietary vitamin D requirements.
Methods
Using double-blind randomization, 34 athletes on the “Ekiden” (long-distance road race) team at University A were divided into a vitamin D group (n = 17, 25 μg/day of vitamin D3 intake) and a placebo group (n = 17, placebo tablet intake). Both groups ate normal meals with either the supplement or placebo included, and all subjects underwent a 31-day dietary survey. The pre- and post-intervention body composition and blood test were measured and compared.
Results
Prior to intervention, the vitamin D intake amount was 16.7 ± 7.2 μg/day, but the serum 25 (OH) D concentration was 28.9 ± 5.7 ng/mL, and 22 (65%) of the 34 subjects had insufficient vitamin D (<30 ng/mL). During the intervention period, the mean amount of vitamin D intake was 40.0 ± 5.5 μg/day in the vitamin D group and 13.4 ± 7.7 μg/day in the placebo group. Serum 25 (OH) D concentrations increased from 30.7 ± 6.7 ng/mL to 35.4 ± 6.6 ng/mL in the vitamin D group and from 27.1 ± 3.9 ng/mL to 28.5 ± 4.4 ng/mL in the placebo group, respectively (p < 0.001, p < 0.01). After intervention, the serum 25 (OH) D concentration in the vitamin D group was significantly higher (p < 0.001). Additionally, the rate of vitamin D sufficiency was 82% in the vitamin D group and 43% in the placebo group, indicating a significant difference (p < 0.01).
Conclusions
Our results demonstrate that post-intervention serum 25 (OH) D concentration was related to both mean vitamin D intake amount during the intervention period and pre-intervention serum 25 (OH) D concentration. However, to better quantify the required amount of vitamin D, further study of the effect of vitamin D supplementation on bone health is needed.
Figure 1
Figure 2
Figure 3