Effects of High-Dose Vitamin D Supplementation and Physical Exercise on Vitamin D Metabolites in Professional Football Players: A Pilot Study.

Physical exercise during a football match significantly increased serum concentrations of multiple vitamin D metabolites.

• Serum concentrations of 25-(OH)D3, 24,25-(OH)2D3, and 3-epi-25-(OH)D3 all increased significantly following match play.
• Increases were by up to 25% (p < 0.001).
• Twenty professional football players participated in the study.
• Blood samples were collected before and after each session using isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS).

High-dose vitamin D3 supplementation combined with physical exercise further amplified increases in vitamin D metabolites compared to exercise alone.

• Players received a single 500,000 IU dose of vitamin D3 before a simulated match.
• 25-(OH)D3 rose by 98% following supplementation combined with exercise (p < 0.001).
• 3-epi-25-(OH)D3 rose by 424% following supplementation combined with exercise (p < 0.001).
• Half of the players (n = 10) received the supplementation dose in the final phase of the randomized placebo-controlled study.

Significant alterations in vitamin D metabolite ratios after exercise and supplementation suggest enhanced metabolic turnover and dynamic regulation of vitamin D pathways.

• Changes in metabolite ratios were observed both after exercise alone and after exercise combined with supplementation.
• The authors interpret these ratio changes as indicative of enhanced metabolic turnover.
• The study measured multiple metabolites including 25-(OH)D3, 24,25-(OH)2D3, and 3-epi-25-(OH)D3.
• Analysis was conducted using the ID-LC-MS/MS method.

A single high-dose of 500,000 IU cholecalciferol supplementation was well tolerated by professional football players.

• The study described the supplementation as 'well tolerated'.
• No adverse effects from the high-dose supplementation were reported.
• The study was a randomized placebo-controlled pilot design with 20 professional football players.
• This was described as a pilot study, and larger trials were noted as needed.

The study employed a three-phase randomized placebo-controlled design to examine vitamin D kinetics in professional football players.

• Phase one involved baseline fitness and blood sample collection.
• Phases two and three involved pre- and post-match measurements during two games.
• In the final phase, half the players received a single 500,000 IU dose of vitamin D3 before a simulated match.
• Twenty professional football players participated.
• Vitamin D metabolites were analyzed using isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS).