Vitamin D Deficiency (10 ng/mL to 30 ng/mL)VitD-FootballNCT07310329
High-Dose Vitamin D Supplementation and Exercise Effects on Vitamin D Metabolites in Professional Football Players
A study testing Vitamin D₃ in people with Vitamin D Deficiency (10 ng/mL to 30 ng/mL) and Athletes, run by Wroclaw University of Health and Sport Sciences at 1 site in Poland.
Trial summary
This randomized, single-blind, placebo-controlled pilot study investigated the effects of high-dose vitamin D₃ supplementation and football-specific physical exercise on vitamin D metabolite concentrations in professional male football players. Read more about this study
- Who is it for?
- Ages 18 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Vitamin D Deficiency (10 ng/mL to 30 ng/mL), Athletes, Football Players
- What is being tested?
- Vitamin D₃
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 20 participants
- Where
- 1 sitePoland
- Study dates
- 27 Apr 2024to 24 Jun 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male professional football players aged 18-35 years
- Actively training and competing in the Polish first football league
- No vitamin D or calcium supplementation during the previous 3 months
- No injuries or illnesses affecting participation
Who cannot join
- Current musculoskeletal injury or illness
- Chronic metabolic, endocrine, or renal disorders
- Use of vitamin D or calcium supplements
- Refusal or inability to sign informed consent
Trial locations and contacts
1 site in 1 country.
Poland1 site
Wroclaw University of Health and Sport Sciences
Wroclaw, Dolnyśląsk, 51-612
About this study
Official title: Effects of High-Dose Vitamin D Supplementation and Physical Exercise on Vitamin D Metabolites in Professional Football Players: A Pilot Study
This randomized, single-blind, placebo-controlled pilot study investigated the effects of high-dose vitamin D₃ supplementation and football-specific physical exercise on vitamin D metabolite concentrations in professional male football players. The study aimed to evaluate the acute response of circulating vitamin D metabolites, including 25-(OH)D₃, 24,25-(OH)₂D₃, and 3-epi-25-(OH)D₃, following a single oral dose of 500,000 IU cholecalciferol combined with high-intensity intermittent exercise typical of competitive football.
Twenty professional football players from a Polish top-division club participated in the study. Participants were randomly assigned to either the supplementation group (SGP) receiving 500,000 IU of vitamin D₃ or the placebo group (PGP) receiving an identical volume of placebo oil. The intervention was administered 48 hours prior to an intra-squad game. Blood samples were collected at three time points: baseline (T3), pre-match (T4), and post-match (T5). The primary outcome was the change in serum 25-(OH)D₃ concentration. Secondary outcomes included changes in 24,25-(OH)₂D₃ and 3-epi-25-(OH)D₃ levels, as well as their ratios. The study also assessed whether physical exercise modulates vitamin D metabolism.
The findings demonstrated that high-dose vitamin D₃ supplementation significantly increased serum 25-(OH)D₃ (↑198%) and 3-epi-25-(OH)D₃ (↑444%) levels, while football-specific exercise itself induced moderate increases in vitamin D metabolites. The results suggest that skeletal muscle may play a key role in vitamin D storage and release in response to exercise. The supplementation was well tolerated, with no adverse events observed.
Read the detailed description
This pilot study was designed to explore the combined effects of high-dose vitamin D₃ supplementation and acute physical exercise on vitamin D metabolism in professional football players. The study responds to growing scientific interest in understanding how vitamin D status influences performance, recovery, and muscle function in athletes. While most previous studies have focused on chronic, low-to-moderate supplementation, this trial examined the response to a single, pharmacological dose of cholecalciferol in a controlled experimental setting.
Study Design
The study employed a randomized, single-blind, placebo-controlled, parallel-group design. Participants were randomly assigned to one of two groups:
Supplementation Group (SGP) - received a single oral dose of 500,000 IU vitamin D₃ (Vigantol Oil, P\&G Health, Germany);
Placebo Group (PGP) - received an identical amount of placebo (vegetable oil).
The supplementation was administered 48 hours before a standardized intra-squad football match (ISG), conducted under conditions simulating a competitive game. All players followed the same training schedule and diet during the study.
Participants
A total of 20 professional male football players (aged 18-35) from a Polish top-league club volunteered to participate. Inclusion criteria included active professional status, regular training participation, and no use of vitamin D or calcium supplements in the previous 3 months. Exclusion criteria included musculoskeletal injuries, metabolic disorders, or refusal to sign informed consent.
Measurements
Blood samples were collected at three time points:
T3: baseline (before supplementation),
T4: 48 hours post-supplementation (pre-match),
T5: immediately after the intra-squad game.
Serum concentrations of 25-(OH)D₃, 24,25-(OH)₂D₃, and 3-epi-25-(OH)D₃ were determined using LC-MS/MS. Additional biochemical variables (hemoglobin, glucose, testosterone, cortisol, ferritin, calcium, CK) were analyzed to monitor physiological status.
Outcomes
Primary Outcome: Changes in serum 25-(OH)D₃ concentrations after supplementation and exercise.
Secondary Outcomes: Changes in 24,25-(OH)₂D₃ and 3-epi-25-(OH)D₃ levels, metabolite ratios.
Ethics
The study was approved by the Ethics Committee of the Wroclaw University of Health and Sport Sciences (Resolution No. 1/2024, March 1, 2024). All participants signed written informed consent.
- Conditions
- Vitamin D Deficiency (10 ng/mL to 30 ng/mL), Athletes, Football Players, Exercise Physiology
- Being tested
- Vitamin D₃, Placebo
- Keywords
- 24,25-(OH)2D3, 3-epi-25-(OH)D3, dietary supplement, physical performance, athletes
- Medical subject headings
- Vitamin D Deficiency
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vitamin D₃Dietary supplement
A single oral dose of 500,000 IU vitamin D₃ (Vigantol Oil, P\&G Health, Germany) was administered 48 hours before the intra-squad football match to assess its acute effects on vitamin D metabolite concentrations.
PlaceboOther
A single oral dose of vegetable oil matching the vitamin D₃ solution in color and consistency was administered 48 hours before the intra-squad football match.
| Study group | Role | What they receive |
|---|---|---|
| Supplementation Group (SGP) | Experimental | Participants in this group received a single oral dose of 500,000 IU of vitamin D₃ (Vigantol Oil, P\&G Health, Germany) 48 hours before the intra-squad football match (ISG). Blood samples were collected before supplementation and both before and after the ISG to evaluate changes in vitamin D metabolites. Receives: Dietary Supplement: Vitamin D₃ |
| Placebo Group (PGP) | Placebo comparator | Participants in this group received a single oral dose of placebo oil identical in color and consistency to the vitamin D₃ solution. Blood samples were collected at the same time points as in the supplementation group to assess vitamin D metabolite changes. Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in serum 25(OH)D₃ concentration
Serum concentrations of 25(OH)D₃ will be measured using isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS). The primary outcome assesses the effect of a single high-dose vitamin D₃ supplementation combined with physical exercise on 25(OH)D₃ concentration in professional football players.
Measured: Baseline (before supplementation), 48 hours after supplementation, and immediately after the football match (2 days after supplementation).
Changes in serum 24,25-dihydroxyvitamin D₃ [24,25(OH)₂D₃] concentration
To evaluate the effect of vitamin D₃ supplementation and physical exercise on 24,25(OH)₂D₃ levels using ID-LC-MS/MS.
Measured: Baseline (T3), 48 hours post-supplementation (T4), and post-exercise (T5)
Secondary outcomes (1)
Changes in metabolite ratios (25(OH)D₃:24,25(OH)₂D₃ and 25(OH)D₃:3-epi-25(OH)D₃)
To assess changes in the ratios between major vitamin D metabolites as indicators of metabolic transformation rate and vitamin D turnover in response to supplementation and physical activity.
Measured: Baseline (before supplementation), 48 hours after supplementation, and immediately after the football match (2 days after supplementation).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Dec 2025
- Study start27 Apr 2024
- Primary completion17 May 2024
- Study completion24 Jun 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Vitamin D Deficiency (10 ng/mL to 30 ng/mL)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants were randomly assigned to one of two parallel groups: a supplementation group receiving a single oral dose of 500,000 IU vitamin D₃ or a placebo group receiving identical placebo oil.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Wroclaw University of Health and Sport Sciences
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Anna Książek, Wroclaw University of Health and Sport Sciences
- Investigators
- Anna Książek, PhD Eng.; Associate Professor, Principal investigator, Department of Biological Principles of Physical Activity ; Wroclaw University of Health and Sport Sciences
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07310329
- Sponsor's protocol ID
- AWF-VitD-Football-2024
- Acronym
- VitD-Football
- Status last verified
- Nov 2025
- First submitted
- 27 Nov 2025
- Last updated
- 30 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared due to privacy considerations and the specific nature of the study population (professional athletes). Aggregated data are available upon reasonable request to the corresponding author.
Publications
Mieszkowski J, Stankiewicz B, Kochanowicz A, Niespodzinski B, Kowalik T, Zmijewski M, Kowalski K, Rola R, Bienkowski T, Antosiewicz J. Ultra-Marathon-Induced Increase in Serum Levels of Vitamin D Metabolites: A Double-Blind Randomized Controlled Trial. Nutrients. 2020 Nov 25;12(12):3629. doi: 10.3390/nu12123629.
PubMed 33255807
Study at a glance
From the registry record, last updated by the sponsor on 30 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of High-Dose Vitamin D Supplementation and Physical Exercise on Vitamin D Metabolites in Professional Football Players: A Pilot Study
- ClinicalTrials.gov ID
- NCT07310329
- Acronym / sponsor ID
- VitD-Football / AWF-VitD-Football-2024
- Conditions
- Vitamin D Deficiency (10 ng/mL to 30 ng/mL), Athletes, Football Players, Exercise Physiology
- Keywords
- 24,25-(OH)2D3, 3-epi-25-(OH)D3, dietary supplement, physical performance, athletes
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Wroclaw University of Health and Sport SciencesUniversity, hospital or other
- Study start
- 27 Apr 2024 (actual)
- Primary completion
- 17 May 2024 (actual)
- Study completion
- 24 Jun 2024 (actual)
- First posted
- 30 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This randomized, single-blind, placebo-controlled pilot study investigated the effects of high-dose vitamin D₃ supplementation and football-specific physical exercise on vitamin D metabolite concentrations in professional male football players. The study aimed to evaluate the acute response of circulating vitamin D metabolites, including 25-(OH)D₃, 24,25-(OH)₂D₃, and 3-epi-25-(OH)D₃, following a single oral dose of 500,000 IU cholecalciferol combined with high-intensity intermittent exercise typical of competitive football.
Twenty professional football players from a Polish top-division club participated in the study. Participants were randomly assigned to either the supplementation group (SGP) receiving 500,000 IU of vitamin D₃ or the placebo group (PGP) receiving an identical volume of placebo oil. The intervention was administered 48 hours prior to an intra-squad game. Blood samples were collected at three time points: baseline (T3), pre-match (T4), and post-match (T5). The primary outcome was the change in serum 25-(OH)D₃ concentration. Secondary outcomes included changes in 24,25-(OH)₂D₃ and 3-epi-25-(OH)D₃ levels, as well as their ratios. The study also assessed whether physical exercise modulates vitamin D metabolism.
The findings demonstrated that high-dose vitamin D₃ supplementation significantly increased serum 25-(OH)D₃ (↑198%) and 3-epi-25-(OH)D₃ (↑444%) levels, while football-specific exercise itself induced moderate increases in vitamin D metabolites. The results suggest that skeletal muscle may play a key role in vitamin D storage and release in response to exercise. The supplementation was well tolerated, with no adverse events observed.
Detailed description
This pilot study was designed to explore the combined effects of high-dose vitamin D₃ supplementation and acute physical exercise on vitamin D metabolism in professional football players. The study responds to growing scientific interest in understanding how vitamin D status influences performance, recovery, and muscle function in athletes. While most previous studies have focused on chronic, low-to-moderate supplementation, this trial examined the response to a single, pharmacological dose of cholecalciferol in a controlled experimental setting.
Study Design
The study employed a randomized, single-blind, placebo-controlled, parallel-group design. Participants were randomly assigned to one of two groups:
Supplementation Group (SGP) - received a single oral dose of 500,000 IU vitamin D₃ (Vigantol Oil, P\&G Health, Germany);
Placebo Group (PGP) - received an identical amount of placebo (vegetable oil).
The supplementation was administered 48 hours before a standardized intra-squad football match (ISG), conducted under conditions simulating a competitive game. All players followed the same training schedule and diet during the study.
Participants
A total of 20 professional male football players (aged 18-35) from a Polish top-league club volunteered to participate. Inclusion criteria included active professional status, regular training participation, and no use of vitamin D or calcium supplements in the previous 3 months. Exclusion criteria included musculoskeletal injuries, metabolic disorders, or refusal to sign informed consent.
Measurements
Blood samples were collected at three time points:
T3: baseline (before supplementation),
T4: 48 hours post-supplementation (pre-match),
T5: immediately after the intra-squad game.
Serum concentrations of 25-(OH)D₃, 24,25-(OH)₂D₃, and 3-epi-25-(OH)D₃ were determined using LC-MS/MS. Additional biochemical variables (hemoglobin, glucose, testosterone, cortisol, ferritin, calcium, CK) were analyzed to monitor physiological status.
Outcomes
Primary Outcome: Changes in serum 25-(OH)D₃ concentrations after supplementation and exercise.
Secondary Outcomes: Changes in 24,25-(OH)₂D₃ and 3-epi-25-(OH)D₃ levels, metabolite ratios.
Ethics
The study was approved by the Ethics Committee of the Wroclaw University of Health and Sport Sciences (Resolution No. 1/2024, March 1, 2024). All participants signed written informed consent.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- Participants were randomly assigned to one of two parallel groups: a supplementation group receiving a single oral dose of 500,000 IU vitamin D₃ or a placebo group receiving identical placebo oil.
| Arm | Type | Receives |
|---|---|---|
| Supplementation Group (SGP) | Experimental | Dietary Supplement: Vitamin D₃Participants in this group received a single oral dose of 500,000 IU of vitamin D₃ (Vigantol Oil, P\&G Health, Germany) 48 hours before the intra-squad football match (ISG). Blood samples were collected before supplementation and both before and after the ISG to evaluate changes in vitamin D metabolites. |
| Placebo Group (PGP) | Placebo comparator | Other: PlaceboParticipants in this group received a single oral dose of placebo oil identical in color and consistency to the vitamin D₃ solution. Blood samples were collected at the same time points as in the supplementation group to assess vitamin D metabolite changes. |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Male professional football players aged 18-35 years
- Actively training and competing in the Polish first football league
- No vitamin D or calcium supplementation during the previous 3 months
- No injuries or illnesses affecting participation
Key exclusion criteria (4 listed)
- Current musculoskeletal injury or illness
- Chronic metabolic, endocrine, or renal disorders
- Use of vitamin D or calcium supplements
- Refusal or inability to sign informed consent
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Vitamin D₃A single oral dose of 500,000 IU vitamin D₃ (Vigantol Oil, P\&G Health, Germany) was administered 48 hours before the intra-squad football match to assess its acute effects on vitamin D metabolite concentrations. | Dietary supplement | Supplementation Group (SGP) |
| PlaceboA single oral dose of vegetable oil matching the vitamin D₃ solution in color and consistency was administered 48 hours before the intra-squad football match. | Other | Placebo Group (PGP) |
Primary outcome
Changes in serum 25(OH)D₃ concentration
Time frame: Baseline (before supplementation), 48 hours after supplementation, and immediately after the football match (2 days after supplementation).
Serum concentrations of 25(OH)D₃ will be measured using isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS). The primary outcome assesses the effect of a single high-dose vitamin D₃ supplementation combined with physical exercise on 25(OH)D₃ concentration in professional football players.
Changes in serum 24,25-dihydroxyvitamin D₃ [24,25(OH)₂D₃] concentration
Time frame: Baseline (T3), 48 hours post-supplementation (T4), and post-exercise (T5)
To evaluate the effect of vitamin D₃ supplementation and physical exercise on 24,25(OH)₂D₃ levels using ID-LC-MS/MS.
1 secondary outcome
Changes in metabolite ratios (25(OH)D₃:24,25(OH)₂D₃ and 25(OH)D₃:3-epi-25(OH)D₃)
Time frame: Baseline (before supplementation), 48 hours after supplementation, and immediately after the football match (2 days after supplementation).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Dec 2025.
- Results publication: PubMed 33255807Mieszkowski J, Stankiewicz B, Kochanowicz A, Niespodzinski B, Kowalik T, Zmijewski M, Kowalski K, Rola R, Bienkowski T, Antosiewicz J. Ultra-Marathon-Induced Increase in Serum Levels of Vitamin D Metabolites: A Double-Blind Randomized Controlled Trial. Nutrients. 2020 Nov 25;12(12):3629. doi: 10.3390/nu12123629.
- Individual participant dataSharing planned: No. Individual participant data will not be shared due to privacy considerations and the specific nature of the study population (professional athletes). Aggregated data are available upon reasonable request to the corresponding author.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Anna Książek, PhD Eng.; Associate Professor principal investigator
Department of Biological Principles of Physical Activity ; Wroclaw University of Health and Sport Sciences
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Vitamin D₃ in people with Vitamin D Deficiency (10 ng/mL to 30 ng/mL) and Athletes, run by Wroclaw University of Health and Sport Sciences at 1 site in Poland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 30 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Poland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in serum 25(OH)D₃ concentration (time frame: Baseline (before supplementation), 48 hours after supplementation, and immediately after the football match (2 days after supplementation).). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07310329, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Dec 2025.