True fractional calcium absorption in Chinese children measured with stable isotopes (42Ca and44Ca)

作者：Warren T.L. Lee, Sophie S.F. Leung, Susan Jane Fairweather‐Tait, Doram. Y. Leung, Heidi S. Y. Tsang, John Eagles, Tom E. Fox, S.H. Wang, Ying-Qi Xu, W. P. Zeng, Joseph T. F. Lau, J.R.L. Masarei · 发表于：British Journal Of Nutrition · 年份：1994 · DOI：10.1079/bjn19940093 · 被引用次数：44 · 研究领域：Magnesium in Health and Disease、Renal function and acid-base balance、Parathyroid Disorders and Treatments

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 betwee...