Lee W T, Leung S S, Fairweather-Tait S J, Leung D M, Tsang H S, Eagles J, Fox T, Wang S H, Xu Y C, Zeng W P
Department of Paediatrics, Faculty of Medicine, Chinese University of Hongkong, Shatin.
Br J Nutr. 1994 Dec;72(6):883-97. doi: 10.1079/bjn19940093.
True fractional Ca absorption (TFCA) was compared in children with different habitual Ca intakes using a double-label stable-isotope technique. Chinese children aged 7 years from Hongkong (n22) and Jiangmen (n12) participated in the study. An oral administration of 8 mg 44Ca in 100 g chocolate milk was given shortly after an intravenous injection of 0.75 mg 42Ca. Ca isotopic ratios were determined in urine samples collected 24 h later using thermal-ionization mass spectrometry. There was no significant difference in TFCA between Jiangmen and Hongkong children (P = 0.16). TFCA of a lower-Ca-intake group (Ca < or = 500 mg/d, n19) with mean Ca intake 359 mg/d was 63.1 (SD 10.7)% and that of a higher-Ca-intake group (Ca > 500 mg/d, n15) with mean Ca intake 862 mg/d was 54.8 (SD 7.3)%; the difference in TFCA was significant (P = 0.016). Serum levels of 25-hydroxycholecalciferol of the children were adequate (33.7 (SD 7.7) ng/ml). The present study indicates that growing children accustomed to a low-Ca diet appear to be able to enhance their absorptive capacity. If it is assumed that dietary Ca absorption by Chinese children resembles their TFCA from a single meal of chocolate milk, then the recommended dietary allowance (RDA) for Ca for Chinese children would be lower than the US RDA (800 mg/d), which is based on an estimated 40% Ca absorption as reported for Caucasian children. A comparative absorption study is necessary to determine whether there is any difference in TFCA between Caucasian and Chinese children.
采用双标记稳定同位素技术，对不同习惯性钙摄入量的儿童的真分数钙吸收（TFCA）进行了比较。来自香港（n = 22）和江门（n = 12）的7岁中国儿童参与了该研究。在静脉注射0.75 mg ⁴²Ca后不久，口服100 g巧克力牛奶中含有的8 mg ⁴⁴Ca。24小时后收集尿液样本，使用热电离质谱法测定钙同位素比率。江门儿童和香港儿童的TFCA没有显著差异（P = 0.16）。钙摄入量较低组（钙≤500 mg/d，n = 19）的平均钙摄入量为359 mg/d，其TFCA为63.1（标准差10.7）%；钙摄入量较高组（钙＞500 mg/d，n = 15）的平均钙摄入量为862 mg/d，其TFCA为54.8（标准差7.3）%；TFCA的差异具有显著性（P = 0.016）。儿童血清25-羟基胆钙化醇水平充足（33.7（标准差7.7）ng/ml）。本研究表明，习惯低钙饮食的成长中儿童似乎能够提高其吸收能力。如果假设中国儿童的膳食钙吸收类似于他们从一顿巧克力牛奶餐中的TFCA，那么中国儿童的钙推荐膳食摄入量（RDA）将低于美国的RDA（800 mg/d），美国的RDA是基于白种儿童报告的估计40%的钙吸收率。有必要进行一项比较吸收研究，以确定白种儿童和中国儿童在TFCA方面是否存在差异。
