High-Dose Vitamin D Supplementation and Exercise Effects on Vitamin D Metabolites in Professional Football Players

NCT07310329 | Completed

• 1 other identifier: AWF-VitD-Football-2024
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief 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. 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.

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

Outcome Measures

Primary Outcomes (2)

• 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.

  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.

  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)

  Baseline (before supplementation), 48 hours after supplementation, and immediately after the football match (2 days after supplementation).

Study Arms (2)

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.

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.

Other: Placebo

Interventions

Vitamin D₃ DIETARY_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.

Supplementation Group (SGP)

Placebo OTHER

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.

Placebo Group (PGP)

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Wroclaw University of Health and Sport Sciences: lead

Study Sites (1)

Wroclaw University of Health and Sport Sciences

Wroclaw, Dolnyśląsk, 51-612, Poland

Location

Related Publications (1)

• 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.

  PMID: 33255807 RESULT

MeSH Terms

Conditions

Vitamin D Deficiency

Interventions

Vitamin D

Condition Hierarchy (Ancestors)

Avitaminosis; Deficiency Diseases; Malnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases

Intervention Hierarchy (Ancestors)

Secosteroids; Steroids; Fused-Ring Compounds; Polycyclic Compounds

Study Officials

• Anna Książek, PhD Eng.; Associate Professor

  Department of Biological Principles of Physical Activity ; Wroclaw University of Health and Sport Sciences

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Single-blind design: participants were unaware of whether they received vitamin D₃ or placebo; the investigator administering supplements was unblinded.
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: 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.

Study Record Dates

• First Submitted: November 27, 2025
• First Posted: December 30, 2025
• Study Start: April 27, 2024
• Primary Completion: May 17, 2024
• Study Completion: June 24, 2024
• Last Updated: December 30, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

PL (1)