Jackman L A, Millane S S, Martin B R, Wood O B, McCabe G P, Peacock M, Weaver C M
Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907-1264, USA.
Am J Clin Nutr. 1997 Aug;66(2):327-333. doi: 10.1093/ajcn/66.2.327.
Achievement of maximal calcium retention during adolescence may influence the magnitude of peak bone mass and subsequently lower the risk of osteoporosis. Calcium retention is generally considered to reach a plateau at a certain calcium intake. To test this hypothesis, calcium balance was measured in 35 females with a mean (+/-SD) age of 12.7 +/- 1.2 y (range: 12-15 y) who consumed from 841 +/- 153 to 2173 +/- 149 mg Ca/d. Subjects ate a basal diet that included a fortified beverage containing different amounts of calcium citrate malate. Twenty-one subjects were studied at two dietary calcium intakes with use of a crossover design. Results from a previous study in 14 subjects who were studied at only one calcium intake were included in the data analysis. Calcium retention was modeled as a nonlinear function of calcium intake that included a parameter representing mean maximal retention. Mean maximal calcium retention was 473 mg/d (95% CI: 245, 701 mg Ca/d). At higher postmenarcheal ages, maximal calcium retention was lower but the intake required to achieve this was not affected. Calcium intake explained 79% and 6%, respectively, of the variation in fecal and urinary calcium excretion. Intake of 1200 mg Ca/d, the recommended dietary allowance for calcium published in 1989, resulted in a mean calcium retention that was 57% of the maximal value (95% CI: 25%, 89%). Intake of 1300 mg Ca/d was the smallest intake that allowed some adolescent females to achieve 100% of maximal calcium retention (95% CI: 26%, 100%). These data support the idea that calcium retention plateaus at a certain calcium intake although it continues to increase at intakes > 2 g/d.
青春期实现最大钙潴留量可能会影响峰值骨量的大小，并随后降低骨质疏松症的风险。一般认为，钙潴留量在一定的钙摄入量时会达到平台期。为了验证这一假设，对35名平均年龄（±标准差）为12.7±1.2岁（范围：12 - 15岁）的女性进行了钙平衡测量，她们的钙摄入量为841±153至2173±149毫克/天。受试者食用一种基础饮食，其中包括一种含有不同量柠檬酸苹果酸钙的强化饮料。21名受试者采用交叉设计在两种膳食钙摄入量下进行研究。对之前仅在一种钙摄入量下研究的14名受试者的研究结果也纳入了数据分析。钙潴留量被建模为钙摄入量的非线性函数，其中包括一个代表平均最大潴留量的参数。平均最大钙潴留量为473毫克/天（95%置信区间：245，701毫克钙/天）。在初潮后年龄较大时，最大钙潴留量较低，但达到此水平所需的摄入量不受影响。钙摄入量分别解释了粪便和尿液钙排泄量变化的79%和6%。1989年公布推荐膳食钙摄入量为1200毫克/天，其导致的平均钙潴留量为最大值的57%（95%置信区间：25%，89%）。1300毫克/天的摄入量是使一些青春期女性能够达到100%最大钙潴留量的最小摄入量（95%置信区间：26%，100%）。这些数据支持了这样一种观点，即尽管在摄入量超过每日2克时钙潴留量仍会继续增加，但钙潴留量在一定的钙摄入量时会达到平台期。
