代谢平衡法与粪便监测法评价藏族成年男子膳食锌吸收率的比较

COMPARISON OF METABOLIC BALANCE AND FECAL MORNITORING METHODS FOR ESTIMATING THE DIETARY ZINC ABSORPTION IN TIBETAN MEN

目的：比较代谢平衡法（MB）和粪便监测法（FM）评价藏族成年男子膳食锌（Zn）吸收率。方法：进行14d人体现场代谢试验,受试者于D5晚一次性口服浓集^67Zn的稳定性同位素示踪剂4.0mg及稀土元素镱（Yb）1.0mg,口服卡红标记、并收集D4-12的粪便和尿液样品,同时收集膳食、饮水样品;用感耦等离子体质谱仪测定粪样^67Zn/^68Zn的比值,并用原子吸收分光光度计分析所收集样品中的锌含量,比较用两种方法测定该人群膳食Zn吸收率的结果。结果：MB和FM评价藏族成年男子膳食Zn吸收率分别为（23.8±3.9）%、（21.4±4.3）%,二者的差异（配对t检验）和相关性（Pearson）均有统计学意义;未吸收的Zn示踪剂和Yb经胃肠道排出情况几乎一致,主要在口服后5d内排出。结论：14d代谢试验评价膳食Zn吸收率时,MB略高于FM,后者的试验期可依据Yb的排出情况缩短至4-5d。两种方法评价的结果都表明藏族成年男子膳食Zn吸收尚可。

Objective： To compare the methods of metabolic balance （MB） and fecal monitoring （FM） for evaluating the dietary zinc （Zn） absorption in Tibetan men. Methods： In 14 d field trial on 16 adult Tibetan men, capsules of carmine were given to mark the feces from D4 to D12, and samples of diet, water, feces and urine were collected during the period. In addition, 4.0 mg zinc tracer （enriched with 67Zn） and 1.0 mg recovery indicator ytterbium （Yb） were orally administrated to the subjects in the evening meal of the D5. The ratio of 67Zn/68Zn in fecal samples was determined by inductively coupled plasma mass spectrometry, and then the zinc absorption was calculated based on the principle of isotope dilution. Results： The dietary zinc absorption in Tibetan men was （23.8±3.9） % evaluated by MB and （21.4±4.3） % by FM with significant difference （by paired-samples t test） and linear correlation （Pearson）. The unabsorbed zinc tracer and Yb had the similar behavior through the digestive tract, mostly excreted within5 d following the intake. Conclusion： In the 14d metabolic period, the dietary zinc absorption from MB was a little higher than that from FM. Using FM, the metabolic period can be shortened to 4-5 days according to excretion of Yb. Both methods suggested that the dietary zinc absorption in the adult Tibetan men was good.