14至18岁青少年维生素D膳食需求量的估计：一项剂量反应、双盲、随机安慰剂对照试验。
Estimation of the dietary requirement for vitamin D in adolescents aged 14-18 y: a dose-response, double-blind, randomized placebo-controlled trial.
作者信息
Smith Taryn J, Tripkovic Laura, Damsgaard Camilla T, Mølgaard Christian, Ritz Christian, Wilson-Barnes Saskia L, Dowling Kirsten G, Hennessy Áine, Cashman Kevin D, Kiely Mairead, Lanham-New Susan A, Hart Kathryn H
机构信息
Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom;
Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.
出版信息
Am J Clin Nutr. 2016 Nov;104(5):1301-1309. doi: 10.3945/ajcn.116.138065. Epub 2016 Sep 21.
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 D 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 clinicaltrials.gov as NCT02150122 and as International Standard Randomized Controlled Trial Number ISRCTN40736890.
背景
青少年是维生素D水平低下的高危人群，但确定膳食维生素D需求量的证据基础仍然薄弱。
目的
旨在确定英国（北纬51°）14 - 18岁白人男性和女性在冬季将血清25 - 羟基维生素D[25(OH)D]浓度维持在建议临界值（25、30、40和50 nmol/L）以上所需的维生素D摄入量分布。
设计
在一项剂量反应试验中，110名青少年（年龄15.9±1.4岁；43%为男性）在冬季被随机分配，每天接受0、10或20μg维生素D补充剂，持续20周。对总维生素D摄入量和干预后血清25(OH)D浓度拟合非线性回归模型，回归预测值估计了将血清25(OH)D浓度维持在特定临界值以上所需的维生素D摄入量。
结果
10μg/d组和20μg/d组的血清25(OH)D平均浓度±标准差分别从49.2±12.0 nmol/L升至56.6±12.4 nmol/L，从51.7±13.4 nmol/L升至63.9±10.6 nmol/L，安慰剂组从46.8±11.4 nmol/L降至30.7±8.6 nmol/L（所有P≤0.001）。估计97.5%的青少年将25(OH)D浓度维持在>25和>30 nmol/L所需的维生素D摄入量分别为10.1和13.1μg/d；将50%的青少年25(OH)D浓度维持在>40 nmol/L所需摄入量为6.6μg/d。由于25(OH)D的反应在46 nmol/L时达到平台期，因此在估计97.5%的青少年将25(OH)D浓度维持在>50 nmol/L所需的维生素D摄入量时存在不确定性，但超过了30μg/d。
结论
冬季白人青少年每天需要摄入10至约30μg维生素D，以将血清25(OH)D浓度维持在>25 - 50 nmol/L，具体取决于所选的血清25(OH)D阈值。该试验在clinicaltrials.gov上注册为NCT02150122，国际标准随机对照试验编号为ISRCTN40736890。
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