Serum 25-hydroxyvitamin D in early autumn to ensure vitamin D sufficiency in mid-winter in professional football players.

BACKGROUND & AIMS: There is growing awareness that vitamin D sufficiency is required for overall optimal health. Most experts agree that 25-hydroxyvitamin D levels of at least 75 nmol/L, as sufficient vitamin D status. Our aim was to investigate the serum 25-hydroxyvitamin D concentration required in mid-October to ensure vitamin D sufficiency in early February, and to assess the rate of vitamin D insufficiency in both seasons.
METHODS: We measured serum 25-hydroxyvitamin D, parathormone, and other related biochemical parameters, in a sample of 28 professional football players homogeneous in factors influencing serum 25-hydroxyvitamin D concentration in a sunny area of southern Spain.
RESULTS: The serum 25-hydroxyvitamin D concentration of 122.7 nmol/L was required; 14.3% reached this level. Ninety-three percent had levels ≥75 nmol/L in mid-October, and 64% had levels <75 nmol/l in early February (χ(2) test, ρ = 0.001).
CONCLUSIONS: Despite the homogeneity in sunlight exposure and vitamin D intake few football players reached the level ensuring vitamin D sufficiency in mid-winter, and two thirds had vitamin D insufficiency in early February. Given our findings, it would be advisable to assess the vitamin D levels in early autumn, although additional studies are necessary.