Schwartz R, Grunes D L, Wentworth R A, Wien E M
J Nutr. 1980 Jul;110(7):1365-71. doi: 10.1093/jn/110.7.1365.
Five leafy vegetables were grown in nutrient solutions in which the natural magnesium was replaced by the stable isotope, 26Mg. They were fed to rats in a test meal together with the extrinsic tracer 28Mg: a) to determine to what extent the instrinsic tracer (26Mg) was exchangeable with extrinsic 28Mg during the digestion and absorption processes, and b) measure the relative Mg availability from the different vegetables. The two tracers, 26Mg and 28Mg, were close to 100% exchangeable, as judged by the ratio of 26Mg/28Mg in the livers. Mean relative Mg absorption from the various vegetables ranged from 108 to 118% of the Mg absorbed from a standard test meal containing MgSO4. There were no statistically significant differences between the rates of Mg absorption from the five vegetables although two of the vegetables tested contained oxalate. The usefulness of stable 26Mg as a tracer in Mg bioavailability tests is discussed.
五种叶菜类蔬菜种植于营养溶液中，其中天然镁被稳定同位素²⁶Mg所取代。将这些蔬菜与外源性示踪剂²⁸Mg一起加入大鼠的试验餐中：a）以确定在消化和吸收过程中内源性示踪剂（²⁶Mg）与外源性²⁸Mg的可交换程度，以及b）测量不同蔬菜中镁的相对可利用性。根据肝脏中²⁶Mg/²⁸Mg的比例判断，这两种示踪剂²⁶Mg和²⁸Mg几乎100%可交换。从各种蔬菜中吸收的镁的平均相对吸收率为含有MgSO₄的标准试验餐中吸收的镁的108%至118%。尽管所测试的两种蔬菜含有草酸盐，但五种蔬菜的镁吸收速率之间没有统计学上的显著差异。本文讨论了稳定的²⁶Mg作为镁生物利用度测试示踪剂的实用性。
