Evans G W, Johnson P E
Am J Clin Nutr. 1977 Jun;30(6):873-8. doi: 10.1093/ajcn/30.6.873.
The absorption of intrinsic 65Zn and extrinsic 65Zn from corn and liver was measured in rats. No significant difference between the absorption of intrinsic- and extrinsic-label was observed. These results indicate that endogenous zinc and exogenous 65Zn enter a common pool prior to being absorbed from the intestine. Since extrinsic 65Zn enters a common pool with intrinsic zinc, whole-body absorption of extrinsic 65Zn can be used to obtain an accurate estimate of the availability of zinc in food. The availability of zinc in human breast milk, in cow's milk, in infant formulas, and in reconstituted dry milk was analyzed by use of the extrinsic label. The zinc in human breast milk was most available (59%) while the zinc in the infant formulas was the least available (26 to 37%). Zinc from both raw and cooked corn was more available than zinc from either cooked or uncooked rat liver.
在大鼠中测量了玉米和肝脏中内源性65锌和外源性65锌的吸收情况。未观察到内源性标记和外源性标记吸收之间的显著差异。这些结果表明，内源性锌和外源性65锌在从肠道吸收之前进入一个共同的池。由于外源性65锌与内源性锌进入一个共同的池，外源性65锌的全身吸收可用于准确估计食物中锌的可利用性。通过使用外源性标记分析了人母乳、牛奶、婴儿配方奶粉和复原干奶中锌的可利用性。人母乳中的锌最易吸收（59%），而婴儿配方奶粉中的锌最不易吸收（26%至37%）。生玉米和熟玉米中的锌比生大鼠肝脏或熟大鼠肝脏中的锌更易吸收。
