Longnecker M P, Stampfer M J, Morris J S, Spate V, Baskett C, Mason M, Willett W C
Department of Epidemiology, University of California, Los Angeles School of Public Health 90024-1772.
Am J Clin Nutr. 1993 Mar;57(3):408-13. doi: 10.1093/ajcn/57.3.408.
The concentration of selenium in toenail clippings and blood reflects dietary intake better than does intake calculated from dietary data because of the highly variable selenium concentration in different samples of the same food. However, the time course of selenium intake in relation to subsequent concentrations in toenail clippings is unclear. Therefore, 12 males were fed high-dose (4.91 mumol Se/d), medium-dose (2.61 mumol Se/d), or control (0.41 mumol Se/d) whole-wheat-bread for 1 y and the concentration of selenium was measured in toenail clippings collected every 12 wk for 2 y. Toenail selenium concentration was unaffected by dietary intake in the previous 3 mo and appeared to provide a time-integrated measure of intake over a period of 26-52 wk. Use of selenium concentration in toenail clippings may be an alternative to blood when a measure of long-term average intake is desired. The absence of a short-term effect of diet on toenail selenium concentration also makes this a useful marker of intake in retrospective studies.
由于同一种食物的不同样本中硒浓度差异很大，所以脚趾甲屑和血液中的硒浓度比根据饮食数据计算出的摄入量更能反映饮食摄入情况。然而，硒摄入量与随后脚趾甲屑中硒浓度的时间关系尚不清楚。因此，12名男性连续1年分别食用高剂量（4.91 μmol硒/天）、中剂量（2.61 μmol硒/天）或对照剂量（0.41 μmol硒/天）的全麦面包，并在2年时间里每12周采集一次脚趾甲屑样本，测定其中的硒浓度。脚趾甲中的硒浓度在前3个月不受饮食摄入的影响，似乎能提供26至52周期间摄入量的时间积分测量值。当需要测量长期平均摄入量时，使用脚趾甲屑中的硒浓度可能是血液检测之外的另一种选择。饮食对脚趾甲硒浓度缺乏短期影响这一点，也使其成为回顾性研究中有用的摄入量标志物。
