Cashman Kevin D, Hill Tom R, Lucey Alice J, Taylor Nicola, Seamans Kelly M, Muldowney Siobhan, Fitzgerald Anthony P, Flynn Albert, Barnes Maria S, Horigan Geraldine, Bonham Maxine P, Duffy Emeir M, Strain J J, Wallace Julie M W, Kiely Mairead
Department of Food and Nutritional Sciences, University College, Cork, Ireland.
Am J Clin Nutr. 2008 Dec;88(6):1535-42. doi: 10.3945/ajcn.2008.26594.
Knowledge gaps have contributed to considerable variation among international dietary recommendations for vitamin D.
We aimed to establish the distribution of dietary vitamin D required to maintain serum 25-hydroxyvitamin D [25(OH)D] concentrations above several proposed cutoffs (ie, 25, 37.5, 50, and 80 nmol/L) during wintertime after adjustment for the effect of summer sunshine exposure and diet.
A randomized, placebo-controlled, double-blind 22-wk intervention study was conducted in men and women aged 20-40 y (n = 238) by using different supplemental doses (0, 5, 10, and 15 microg/d) of vitamin D(3) throughout the winter. Serum 25(OH)D concentrations were measured by using enzyme-linked immunoassay at baseline (October 2006) and endpoint (March 2007).
There were clear dose-related increments (P < 0.0001) in serum 25(OH)D with increasing supplemental vitamin D(3). The slope of the relation between vitamin D intake and serum 25(OH)D was 1.96 nmol x L(-1) x microg(-1) intake. The vitamin D intake that maintained serum 25(OH)D concentrations of >25 nmol/L in 97.5% of the sample was 8.7 microg/d. This intake ranged from 7.2 microg/d in those who enjoyed sunshine exposure, 8.8 microg/d in those who sometimes had sun exposure, and 12.3 microg/d in those who avoided sunshine. Vitamin D intakes required to maintain serum 25(OH)D concentrations of >37.5, >50, and >80 nmol/L in 97.5% of the sample were 19.9, 28.0, and 41.1 microg/d, respectively.
The range of vitamin D intakes required to ensure maintenance of wintertime vitamin D status [as defined by incremental cutoffs of serum 25(OH)D] in the vast majority (>97.5%) of 20-40-y-old adults, considering a variety of sun exposure preferences, is between 7.2 and 41.1 microg/d.
知识空白导致国际上维生素D膳食建议存在显著差异。
我们旨在确定在调整夏季阳光照射和饮食的影响后，冬季维持血清25-羟基维生素D[25(OH)D]浓度高于几个建议临界值（即25、37.5、50和80 nmol/L）所需的膳食维生素D分布情况。
对20 - 40岁的男性和女性（n = 238）进行了一项为期22周的随机、安慰剂对照、双盲干预研究，在整个冬季使用不同补充剂量（0、5、10和15 μg/d）的维生素D(3)。在基线（2006年10月）和终点（2007年3月）通过酶联免疫测定法测量血清25(OH)D浓度。
随着维生素D(3)补充量增加，血清25(OH)D有明显的剂量相关增加（P < 0.0001）。维生素D摄入量与血清25(OH)D之间关系的斜率为1.96 nmol × L(-1) × μg(-1)摄入量。在97.5%的样本中维持血清25(OH)D浓度>25 nmol/L所需的维生素D摄入量为8.7 μg/d。该摄入量在有阳光照射的人群中为7.2 μg/d，有时有阳光照射的人群中为8.8 μg/d，避免阳光照射的人群中为12.3 μg/d。在97.5%的样本中维持血清25(OH)D浓度>37.5、>50和>80 nmol/L所需的维生素D摄入量分别为19.9、28.0和41.1 μg/d。
考虑到各种阳光照射偏好，在绝大多数（>97.5%）20 - 40岁成年人中确保维持冬季维生素D状态[由血清25(OH)D的递增临界值定义]所需的维生素D摄入量范围为7.2至41.1 μg/d。
