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目的:测定山东农村儿童代表性膳食中锌(Zn)的人体吸收率。方法:模拟山东农村典型膳食模式,采用富集的天然低丰度稳定性同位素67Zn标记ZnCl2,使用热电离质谱法(TIMS)检测膳食和粪便中总锌含量与67Zn/68Zn比值,计算锌的真吸收率;使用原子吸收分光光度计穴AAS雪测定膳食与粪便的总锌,计算锌的表观吸收率。同时测定影响锌吸收的因子膳食脂肪、蛋白、植酸、纤维素和维生素C(Vc)的含量,计算日平均摄入量,将其结果与我国儿童每日推荐膳食营养素摄入量(RNIs)进行比较。结果:锌的真吸收率为(12.94±3.32)%,锌的表观吸收率为(22.37±1.59)%,两者差异有统计学意义(P<0.05)。锌的平均日摄入量为11.16mg,占RNI的111.6%,高于推荐量。蛋白质和Vc的日摄入量分别为31.2g与13.3mg,占RNIs的56.73%和29.60%,低于推荐量。脂肪、植酸和膳食纤维的日摄入量较高。结论:在蛋白质和Vc的日摄入量较低,脂肪、植酸和膳食纤维的日摄入量较高的条件下,锌的真吸收率较低。
OBJECTIVE: To determine the human absorption rate of zinc (Zn) in the representative diet of children in Shandong rural areas. Methods: The typical dietary patterns in Shandong rural areas were simulated. Enrichment of natural low abundance stable isotope 67Zn labeled ZnCl2 was used to determine the ratio of total zinc to 67Zn / 68Zn in dietary and fecal samples by using thermal ionization mass spectrometry (TIMS) Absorbency; AAS snow was used to determine the total dietary zinc and zinc of the faeces by atomic absorption spectrophotometer, and the apparent zinc absorption rate was calculated. At the same time, the contents of dietary fat, protein, phytic acid, cellulose and vitamin C (Vc) that affect the zinc absorption were determined, and the average daily intake was calculated. The results were compared with the daily recommended dietary nutrient intake (RNIs) Compare. Results: The true absorption rate of zinc was (12.94 ± 3.32)%, while the apparent absorption rate of zinc was (22.37 ± 1.59)%, the difference was statistically significant (P <0.05). The average daily intake of zinc was 11.16mg, accounting for 111.6% of RNI, higher than the recommended amount. Daily intakes of protein and Vc were 31.2g and 13.3mg, accounting for 56.73% and 29.60% of RNIs respectively, lower than the recommended level. Daily intake of fat, phytic acid and dietary fiber is higher. CONCLUSIONS: True daily absorption of zinc is low with lower daily intakes of protein and Vc, and higher daily intakes of fat, phytate and dietary fiber.