This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Research article
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, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Research article
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
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