The American journal of clinical nutrition
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Randomized Controlled Trial Comparative Study
Increased vitamin D intake differentiated according to skin color is needed to meet requirements in young Swedish children during winter: a double-blind randomized clinical trial.
Background: Dark skin and low exposure to sunlight increase the risk of vitamin D insufficiency in children. Objective: The aim of the study was to evaluate the amount of vitamin D needed to ascertain that most children >4 y of age attain sufficient serum 25-hydroxyvitamin D [S-25(OH)D; i.e., ≥50 nmol/L] during winter regardless of latitude and skin color. Design: In a longitudinal, double-blind, randomized, food-based intervention study, 5- to 7-y-old children from northern (63°N) and southern (55°N) Sweden with fair (n = 108) and dark (n = 98) skin were included. ⋯ By using 95% prediction intervals for 30 and 50 nmol S-25(OH)D/L, intakes of 6 and 20 μg/d are required in fair-skinned children, whereas 14 and 28 μg/d are required in children with dark skin. Conclusion: Children with fair and dark skin require vitamin D intakes of 20 and 28 μg/d, respectively, to maintain S-25(OH)D ≥50 nmol/L, whereas intakes of 6 and 14 μg/d, respectively, are required to maintain concentrations ≥30 nmol/L during winter. This trial was registered at clinicaltrials.gov as NCT01741324.