Vitamin D is crucial for athletes' health and performance. Although the exact vitamin D requirements for athletes have not been established, maintaining 25(OH)D levels of at least 40 ng/ml is considered beneficial.
This study aimed to determine whether an individual loading dose formula for vitamin D supplementation is suitable to meet a target value of 40 ng/ml and is more effective than standardized supplementation.
In a 10-week supplementation study during the winter months in Germany, 90 athletes with insufficient vitamin D levels (25(OH)D<30ng/ml) were randomly assigned to receive either a universal dose of 2000 IU/day of vitamin D or a loading dose of 4000 IU/day, followed by a maintenance dose of 1000 IU/day.
Total 25(OH)D concentration was measured from dried blood spots at three time points: at baseline, at the computed date of 40ng/ml, and after the 10-week period. Additionally, a vitamin D-specific questionnaire was issued.
On the day when 25(OH)D blood concentrations of 40 ng/ml were calculated to prevail, the individualized group had a significantly higher 25(OH)D level than the standardized group (41.1+-10.9 ng/ml vs. 32.5+-6.4 ng/ml, p<0.001).
This study demonstrated that the examined formula is suitable for athletes to achieve a 25(OH)D concentration of 40 ng/ml. This indicates that a personalized approach is more effective than a one-size-fits-all approach in restoring adequate vitamin D levels in athletes.