Dietary Protein-Induced Increases in Urinary Calcium Are Accompanied by Similar Increases in Urinary Nitrogen and Urinary Urea: A Controlled Clinical Trial
Dietary Protein-Induced Increases in Urinary Calcium Are Accompanied by Similar Increases in Urinary Nitrogen and Urinary Urea: A Controlled Clinical Trial
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DOI：
10.1016/j.jand.2012.11.002
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发表时间：
2013-03-01
影响因子：
4.8
通讯作者：
Insogna, Karl L.
中科院分区：
文献类型：
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作者：
Bihuniak, Jessica D.;Simpson, Christine A.;Insogna, Karl L.
为了确定尿尿素作为膳食蛋白质摄入指数的有用性，10名绝经后妇女参加并完成了一项随机，双盲，交叉喂养试验，从2008年9月至2010年5月，比较了10天的45 g乳清补充剂与10天的45 g麦芽糊精对照。在第0、7和10天测量尿氮、尿钙、尿尿素和骨转换标志物。采用配对样本t检验、Pearson相关统计和简单线性回归评估治疗之间的差异和尿代谢物之间的相关性。补充乳清后，尿氮/尿肌酐从12.3 +/- 1.7 g/g（99.6 +/- 13.8 mmol/mmol）上升至16.8 +/- 2.2 g/g（135.5 +/- 17.8 mmol/mmol），但麦芽糊精没有变化。补充乳清导致尿钙升高4.76 +/- 1.84 mg（1.19 +/- 0.46 mmol），而骨转换标志物没有变化。由于我们的目标是从尿氮/尿肌酐估计蛋白质摄入量，因此我们使用我们的数据建立了以下方程：蛋白质摄入量（g/天）= 71.221+ 1.719 x（尿氮，g）/肌酐，g）（R=0.46，R-2=0.21）。作为尿氮/尿肌酐的更快速且成本更低的替代方案，我们接下来确定尿尿素是否可以预测蛋白质摄入量，并发现蛋白质摄入量（g/天）= 63.844+ 1.11 x（尿尿素，g/肌酐，g）（R=0.58，R-2=0.34）。这些数据表明，尿尿素/尿肌酐至少与尿氮一样是膳食蛋白质摄入量的标志物，并且在营养干预试验中更容易定量。Acad Nutr Diet. 2013;113：447-451.
To determine the usefulness of urinary urea as an index of dietary protein intake, 10 postmenopausal women were enrolled in and completed a randomized, double-blind, cross-over feeding trial from September 2008 to May 2010 that compared 10 days of a 45-g whey supplement with 10 days of a 45-g maltodextrin control. Urinary nitrogen, urinary calcium, urinary urea, and bone turnover markers were measured at days 0, 7, and 10. Paired sample t tests, Pearson's correlation statistic, and simple linear regression were used to assess differences between treatments and associations among urinary metabolites. Urinary nitrogen/urinary creatinine rose from 12.3 +/- 1.7 g/g (99.6 +/- 13.8 mmol/mmol) to 16.8 +/- 2.2 g/g (135.5 +/- 17.8 mmol/mmol) with whey supplementation, but did not change with maltodextrin. Whey supplementation caused urinary calcium to rise by 4.76 +/- 1.84 mg (1.19 +/- 0.46 mmol) without a change in bone turnover markers. Because our goal was to estimate protein intake from urinary nitrogen/urinary creatinine, we used our data to develop the following equation: protein intake (g/day)= 71.221+1.719x(urinary nitrogen, g)/creatinine, g) (R=0.46, R-2=0.21). As a more rapid and less costly alternative to urinary nitrogen/urinary creatinine, we next determined whether urinary urea could predict protein intake and found that protein intake (g/day)= 63.844+1.11x(urinary urea, g/creatinine, g) (R=0.58, R-2=0.34). These data indicate that urinary urea/urinary creatinine is at least as good a marker of dietary protein intake as urinary nitrogen and is easier to quantitate in nutrition intervention trials. Acad Nutr Diet. 2013;113:447-451.