Estimation of the dietary requirement for vitamin D in adolescents aged 14-18 y: a dose-response, double-blind, randomized placebo-controlled trial

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BACKGROUND: Adolescents are a population group at high risk of low vitamin D status, yet the evidence base for establishing dietary vitamin D requirements remains weak.

OBJECTIVE: The aim was to establish the distribution of vitamin D intakes required to maintain serum 25-hydroxyvitamin D [25(OH)D] concentrations above proposed cutoffs (25, 30, 40, and 50 nmol/L) during winter in white males and females (14-18 y of age) in the United Kingdom (51°N).

DESIGN: In a dose-response trial, 110 adolescents (aged 15.9 ± 1.4 y; 43% males) were randomly assigned to receive 0, 10, or 20 μg vitamin D3 supplements/d for 20 wk during winter. A nonlinear regression model was fit to total vitamin D intake and postintervention serum 25(OH)D concentrations, and regression-predicted values estimated the vitamin D intakes required to maintain serum 25(OH)D concentrations above specific cutoffs.

RESULTS: Mean ± SD serum 25(OH)D concentrations increased from 49.2 ± 12.0 to 56.6 ± 12.4 nmol/L and from 51.7 ± 13.4 to 63.9 ± 10.6 nmol/L in the 10- and 20-μg/d groups, respectively, and decreased in the placebo group from 46.8 ± 11.4 to 30.7 ± 8.6 nmol/L (all P ≤ 0.001). Vitamin D intakes required to maintain 25(OH)D concentrations >25 and >30 nmol/L in 97.5% of adolescents were estimated to be 10.1 and 13.1 μg/d, respectively, and 6.6 μg/d to maintain 50% of adolescents at concentrations >40 nmol/L. Because the response of 25(OH)D reached a plateau at 46 nmol/L, there is uncertainty in estimating the vitamin D intake required to maintain 25(OH)D concentrations >50 nmol/L in 97.5% of adolescents, but it exceeded 30 μg/d.

CONCLUSION: Vitamin D intakes between 10 and ∼30 μg/d are required by white adolescents during winter to maintain serum 25(OH)D concentrations >25-50 nmol/L, depending on the serum 25(OH)D threshold chosen. This trial was registered at as NCT02150122 and as International Standard Randomized Controlled Trial Number ISRCTN40736890.

TidsskriftAmerican Journal of Clinical Nutrition
Udgave nummer5
Sider (fra-til)1301-1309
Antal sider9
StatusUdgivet - 2016

Bibliografisk note

CURIS 2016 NEXS 268

ID: 166241090