年轻男性和老年男性锌吸收与保留的稳定同位素研究。

Stable isotope studies of zinc absorption and retention in young and elderly men.

作者信息

Turnlund J R, Durkin N, Costa F, Margen S

出版信息

J Nutr. 1986 Jul;116(7):1239-47. doi: 10.1093/jn/116.7.1239.

DOI:10.1093/jn/116.7.1239

Abstract

Zinc absorption was determined with 67Zn and 70Zn, stable isotopes of zinc, in six young men and six elderly men who were confined to a metabolic unit for 12 wk. Their purified formula diets, supplemented with select food items, contained 15 mg of zinc per day. Zinc absorption was determined twice for each subject by combining zinc enriched with either 70Zn or 67Zn with the formula diet. Serum, urinary, and fecal zinc and zinc balance were determined by atomic absorption spectrometry. Zinc absorption averaged 17% in elderly men, significantly less than average zinc absorption of 31% in young men. Serum zinc was also lower in elderly men and increased in both groups during the course of the study. Zinc balance did not differ between groups, and endogenous zinc losses were less in the elderly than in the young men. The results suggest that while zinc absorption is less in elderly men than in young men, the lower absorption may reflect a lower requirement for absorbed zinc by the elderly. Alternatively, less efficient zinc absorption could result in decreased endogenous losses.

摘要

采用锌的稳定同位素67Zn和70Zn，对6名青年男性和6名老年男性进行了锌吸收测定，这些受试者被限制在代谢单元中12周。他们的纯化配方饮食添加了特定食物，每天含有15毫克锌。通过将富含70Zn或67Zn的锌与配方饮食混合，对每个受试者进行了两次锌吸收测定。采用原子吸收光谱法测定血清、尿液和粪便中的锌以及锌平衡。老年男性的锌吸收平均为17%，显著低于青年男性31%的平均锌吸收。老年男性的血清锌也较低，且两组在研究过程中血清锌均有所增加。两组之间的锌平衡没有差异，老年男性的内源性锌损失比青年男性少。结果表明，虽然老年男性的锌吸收比青年男性少，但较低的吸收可能反映出老年人对吸收锌的需求较低。或者，较低效的锌吸收可能导致内源性损失减少。