硒的人体最大安全摄入量研究 五、硒的日摄入量和血、尿以及组织中硒含量的相关性分析

用回归分析方法,在双对数纸上计算并绘制出日平均硒摄入量和全血硒浓度、24小时尿硒排出量及奶硒浓度间的回归方程式及线图。通过这些回归方程,可从人的全血或其它体液中硒的含量计算出日平均硒摄入量。同时又测定出全血与发、趾甲及指甲组织中硒含量间的相关性,从而可将其它组织中硒的浓度换算为全血硒浓度,最终计算出日平均硒摄入量。此外,通过血浆硒和24小时尿硒排出量间的相关性可将血浆硒浓度换算为日平均硒摄入量。在高硒地区,由于每日硒进食量的变动性,通过短期内的膳食调查,难以测出某一受试者有代表性的日硒摄入量。由于血硒浓度的相对稳定性,通过血硒值换算为摄入量,结果稳定而具有代表性。     

硒的人体最大安全摄入量的研究 一、居民硒的日摄入量和组织硒的含量

在恩施高硒及邻近地区选择了高、中及低硒三个试验点,各点间的距离不超过20～30公里。低、中及高硒点成年居民年平均硒摄入量分别为66.3,196.4及1338.4μg,组织中硒含量随硒摄入量的增加而增加。在摄入量处于营养水平时,血硒的变化具有一定的代表性。但当硒摄入量超过正常水平时,血硒的反应不如发及甲硒灵敏,后者硒浓度的变化与尿近似,它们似具有明显的排泄功能。文中界限摄入量即根据血硒值计算而得。本研究课题总的实验设计在文中作了纲要性的叙述。     

硒的人体最大安全摄入量的研究——一、居民硒的日摄入量和组织硒的含量

在恩施高硒及邻近地区选择了高、中及低硒三个试验点,各点间的距离不超过20～30公里。低、中及高硒点成年居民年平均硒摄入量分别为66.3,196.4及1338.4μg,组织中硒含量随硒摄入量的增加而增加。在摄入量处于营养水平时,血硒的变化具有一定的代表性。但当硒摄入量超过正常水平时,血硒的反应不如发及甲硒灵敏,后者硒浓度的变化与尿近似,它们似共有明显的排泄功能。文中界限摄入量即根据血硒值计算而得。本研究课题总的实验设计在文中作了纲要性的叙述。     

硒的人体最大安全摄入量研究 六、硒的最高界限摄入量和最大安全摄入量

体检349名成年居民结果,发现血硒水平在1.02μg/ml以下者无硒中毒病人,又5名指甲变形长期不能恢复正常者,他们中间最低血浓度为1.054μg/ml(硒日摄入量910μg)。生化检查结果发现当血硒浓度上升到1μg/ml(硒日摄入量850μg)时,凝血酶原时间延长的病例显著上升;此外,在血硒浓度接近0.9μg/ml(硒日摄入量743μg)时,血浆硒/红血球硒的比值下降至低血硒状态时的1/3至1/4。据上述结果,界限日硒摄入量应在750～850μg范围内。考虑到个体差异,建议用2.0作为安全因子,即最高安全摄入量为400μg。又考虑我国高硒区的某些具体情况如居民适应性及环境中某些拮抗元素的存在等,建议在高硒区用1.3作为安全因子,即最高安全摄入量约为每日550μg。     

硒的人体最大安全摄入量研究 六、硒的最高界限摄入量和最大安全摄入量

体检349名成年居民结果,发现血硒水平在1.02μg/ml以下者无硒中毒病人,又5名指甲变形长期不能恢复正常者,他们中间最低血浓度为1.054μg/ml(硒日摄入量910μg)。生化检查结果发现当血硒浓度上升到1μg/ml(硒日摄入量850μg)时,凝血酶原时间延长的病例显著上升;此外,在血硒浓度接近0.9μg/ml(硒日摄入量743μg)时,血浆硒/红血球硒的比值下降至低血硒状态时的1/3至1/4。据上述结果,界限日硒摄入量应在750～850μg范围内。考虑到个体差异,建议用2.0作为安全因子,即最高安全摄入量为400μg。又考虑我国高硒区的某些具体情况如居民适应性及环境中某些拮抗元素的存在等,建议在高硒区用1.3作为安全因子,即最高安全摄入量约为每日550μg。     

北京市机关职工及托幼儿童每日硒摄入量的评价

北京市内居民平均每日膳食硒摄入量为66.4μg,托幼儿童为34.7μg,已达到目前的推荐膳食供给量标准。在成人膳食中,硒主要来源于谷类,占摄入量的63.6％,其次是动物性食品,占25.9％,其它植物性食品占10.5％;儿童膳食硒主要来源于谷类和动物性副食,各占48.9％和44.3％。 全血平均硒含量为0.146ppm,发硒含量0.578ppm。全血硒和发硒含量与每日膳食硒摄入量间均呈显著的正相关。 汞、砷及镉的每日摄入量分别为3.4,52.7和42.7μg,未超过正常地区的允许范围,不致于显著增加硒的需要量。 由于调查对象硒的营养状况正常,且每日摄入的拮抗元素为量不多,故所调查出的每日硒摄入量应为我国健康人的正常摄入量,可供制定供给量时参考。     

恩施高硒区居民膳食硒摄入量监测报告

目的:通过比对恩施高硒区及其他地区居民膳食硒摄入量、血硒水平,了解不同时期恩施高硒区居民膳食硒摄入量。方法:对20世纪60年代、80年代及2012年的膳食硒摄入量、全血硒水平及癌症患病情况进行比对。结论:恩施高硒区居民每日膳食硒摄入量、血硒水平已经趋于正常;高硒区的癌症患者数量明显少于低硒区,适量硒摄入对癌症有一定的预防作用。     

人和大鼠尿中三甲基硒离子(TMSe~+)排出量和硒摄入量的关系

建立了用离子交换层析法测定人及动物尿中三甲基硒离子(TM-Se~+)的分析方法,方法的精密度及准确度良好,可以用于不同硒状态尿中三甲基硒离子的测定。给大鼠注射大剂量亚硒酸钠后,在一定剂量下,TMSe~+的排出率随剂量的增加而上升,超过剂量后则变化不大。测定高硒地区居民尿中TMSe~+后,发现尿中TMSe~+-Se的浓度和排出量均相应的随尿硒(T-Se)浓度及总排出量的增加而增加,但TMSe~+-Se/T-Se比率的增加只限于尿中T-Se排出量在80μg以下的12小时夜尿样品。     

硒的人体最大安全摄入量研究 四、硒摄入量不同时人尿中三甲基硒离子(TMSe~+)排出量

用离子交换层析法测定了湖北恩施高硒和其邻近地区居民以及口服补充不同剂量硒的北京居民尿中三甲基硒离子硒(TMSe~+-Se)的排出量.现场和补充实验的结果显示尿中TMSe~+-Se排出量随尿总硒(T-Se)量的增加而增加,但TMSe~+-Se不是尿硒的主要成分,即使在慢性硒中毒的居民尿中TMSe~+-Se排出量也只占尿总硒(T-Se)的5%左右.T-Se量和TMSe~+-Se/T-Se比值之间无显著的正相关.因此,尿中TMSe~+-Se排出量不能作为人体摄入过量硒或硒中毒的生化指标.     

硒的人体最大安全摄入量研究 四、硒摄入量不同时人尿中三甲基硒离子(TMSe~+)排出量

用离子交换层析法测定了湖北恩施高硒和其邻近地区居民以及口服补充不同剂量硒的北京居民尿中三甲基硒离子硒(TMSe~+-Se)的排出量。现场和补充实验的结果显示尿中TMSe~+-Se排出量随尿总硒(T-Se)量的增加而增加,但TMSe~+-Se不是尿硒的主要成分,即使在慢性硒中毒的居民尿中TMSe~+Se排出量也只占尿总硒(T-Se)的5％左右。T-Se量和TMSe~+-Se/T-Se比值之间无显著的正相关。因此,尿中TMSe~+-Se排出量不能作为人体摄入过量硒或硒中毒的生化指标。     

Daily Intake and Serum Levels of Copper,Selenium and Zinc According to Glucose Metabolism: Cross-Sectional and Comparative Study

Trace elements play an important role in metabolism. We compared the daily intake and serum concentrations of copper (Cu), selenium (Se), and zinc (Zn) across a spectrum of glucose tolerance status in a representative U.S. population. Daily intake and serum concentrations of Cu, Zn and Se in 5087 adults from the 2011–2016 National Health and Nutrition Examination Survey (NHANES) were examined and compared to normal (NGT) and abnormal (AGT) glucose tolerance and the presence of diabetes mellitus (DM). Other than Zn deficiency (21.15%), the prevalence of Zn, Se, and Cu excess and Se and Cu deficiency were low (<4.00%). As compared to the NGT group, Cu and Se supplementation was higher in the AGT and DM groups (p < 0.0001 for all). Serum Se and Zn, but not Cu, concentrations were highly correlated with daily intake (p < 0.0001 for both). As compared to the NGT group, serum Cu concentration was highest in the AGT group (p = 0.03), serum Se concentration was highest in the DM group (p < 0.0001), and serum Zn concentration was highest in the AGT group (p < 0.0001). Serum Se and Zn concentration was correlated with daily Se and Zn intake. Even within the reference range for serum Cu, Se, and Zn concentrations, a higher serum concentration of Cu, Se, and Zn was associated with abnormal glucose metabolism. Although the casual relationship remains to be elucidated, these data suggest caution in Cu, Se and Zn supplementation in non-deficient individuals.     

Longitudinal study on the selenium status of healthy adults in Finland during 1975–1984

A systematic study on the change in selenium (Se) status of a Finnish subpopulation is described. Serum samples were obtained bimonthly between 1975 and 1984 and 24-hr urine samples in 1983. The mean serum Se concentration varied between 52 ug/l in 1977 to 99 ug/l in 1982. The correlation between the annual serum Se concentration and estimated national Se intake was, r=0.89. The mean daily urinary Se excretion was 16.7 ug, which converted to daily intake, 33 ug was in fairly good agreement with the estimated national Se intake, 38 ug. Strict quality control measures were taken including analysis of both internal and external standard materials in each series throughout the study. The results demonstrate that the serum Se concentration has varied widely in Finland between 1975 and 1984 due to temporary importation of Se- rich grain and that serum Se is a useful indicator of Se status.     

A Review of Dietary Selenium Intake and Selenium Status in Europe and the Middle East

This is a systematic review of existing data on dietary selenium (Se) intake and status for various population groups in Europe (including the United Kingdom (UK)) and the Middle East. It includes English language systematic reviews, meta-analyses, randomised controlled trials, cohort studies, cross-sectional and case-control studies obtained through PUBMED searches from January, 2002, to November, 2014, for European data and from 1990 to November 2014, for Middle Eastern data. Reports were selected if they included data on Se intake and status. The search identified 19 European/UK studies and 15 investigations in the Middle East that reported Se intake and Se concentration in water and/or food and 48 European/UK studies and 44 investigations in the Middle East reporting Se status. Suboptimal Se status was reported to be widespread throughout Europe, the UK and the Middle East, and these results agreed with previous reports highlighting the problem. Eastern European countries had lower Se intake than Western European countries. Middle Eastern studies provided varying results, possibly due to varying food habits and imports in different regions and within differing socioeconomic groups. In conclusion, Se intake and status is suboptimal in European and Middle Eastern countries, with less consistency in the Middle East.     

On supplementing the selenium intake of New Zealanders. 2. Prolonged metabolic experiments with daily supplements of selenomethionine, selenite and fish

1. The daily intake of selenium by three subjects was supplemented with 100 microgram Se as selenomethionine (Semet-Se) or sodium selenite (selenite-Se)/d for 10-11 weeks, or with 65 microgram Se as in mackerel (Scomber japonicus) (fish-Se)/d for 4 weeks. 2. Urinary and faecal excretion of Se was measured and also Se concentration in whole blood, plasma and erythrocytes. Measurements on blood were made at intervals after supplementation had ceased. 3. Selenite-Se was not as well absorbed (0.46 of the intake) during the first 4 weeks as Semet-Se (0.75 of the intake) and fish Se (0.66 of the intake). 4. Blood Se increased steadily with Semet-Se, from 0.08 to 0.18 microgram Se/ml, but more slowly with selenite-Se, reaching a plateau in 7-8 weeks at 0.11 microgram Se/ml. Plasma Se increased more rapidly with Semet-Se than with selenite-Se, so that initially with Semet-Se plasma Se was greater than erythrocyte Se. 5. Daily urinary excretion increased with all forms of supplement, with initially a greater proportion of absorbed selenite-Se being excreted than Semet-Se or fish-Se. A close relationship was found between plasma Se and 24 h urinary excretion. The findings suggested that there was a rapid initial excretion of presumably unbound Se then a slower excretion of residual unbound, loosely bound or bound Se. 6. Total retentions of 3.5 mg selenite-Se and 4.5 mg Semet-Se were large when compared with an estimate of body content of 6 mg Se, derived in another paper (Stewart, Griffiths, Thomson & Robinson, 1978). Retention of Semet-Se and fish-Se appeared to be reflected in blood Se, whereas for selenite-Se, blood Se reflected retention for only a short period after which Se appeared to be retained without altering the blood Se. This suggested that Semet-Se and selenite-Se were metabolized differently. 7. A double blind-dosing trail with 100 microgram Semet-Se was carried out for 12 weeks on twenty-four patients with muscular complaints in Tapanui, a low-Se-soil area. Blood Se increased in the experimental group (from 0.067 to 0.143 microgrm Se/ml); clinical findings were not conclusive and will be presented elsewhere. 8. Bood Se was measured in New Zealand residents before travelling to Europe or to North America. On return their blood Se was increased, and depending upon the period of time spent outside New Zealand some values reached concentrations found in visitors and new settlers to New Zealand. 9. The results from these studies and the earlier studies of single and multiple dosing have been used to look at the various criteria in use for assessing Se status of subjects. It is suggested that plasma Se be used in preference to 24 h urinary excretion, and in addition to whole blood Se and glutathione peroxidase (EC 1.11.1.9) activity.     

Daily Dietary Selenium Intake in a High Selenium Area of Enshi,China

Enshi is a high selenium (Se) region in Hubei, China, where human selenosis was observed between 1958 and 1963. This study investigated the daily dietary Se intake of residents in Shadi, a town located 72 km northeast of Enshi City, to assess the risk of human selenosis in the high Se area. Foods consumed typically by the local residents and their hair samples were analyzed for total Se concentration. Concentrations of Se in different diet categories were as follows: cereals: 0.96 ± 0.90 mg kg⁻¹ DW in rice and 0.43 ± 0.55 mg kg⁻¹ DW in corn; tuber: 0.28 ± 0.56 mg kg⁻¹ in potato and 0.36 ± 0.12 mg kg⁻¹ in sweet potato; vegetables: ranging from 0.23 ± 1.00 mg kg⁻¹ in carrot to 1.57 ± 1.06 mg kg⁻¹ in kidney bean; animal proteins: 1.99 ± 1.11 mg kg⁻¹ in chicken and egg. Based on the food Se concentrations and the daily per-capita consumption, the estimated daily Se intake in Shadi was 550 ± 307 µg per capita. Moreover, the Se concentrations in the hairs of local adult residents were 3.13 ± 1.91 mg kg⁻¹ (n = 122) and 2.21 ± 1.14 mg kg⁻¹ (n = 122) for females and males, respectively, suggesting that females might be exposed to higher levels of Se from daily cooking. Although there was no human selenosis occurrence in recent years, the high level of the daily Se intake suggested that the potential risk of selenosis for local residents, especially females, might be a matter of concern.     

硒的人体最大安全摄入量研究 三、恩施高硒点居民血和发中某些拮抗金属元素的含量

恩施高硒区的硒来源于煤.煤中除硒外,尚有高含量的氟.此外,本地尚分布有丰富的硫铁矿,居民用作生产硫磺.由于环境污染严重,因此在观察硒的毒性时,应考虑其它有关元素的含量.本文测定了居民发中的Cd,Hg,As以及全血中的Cd,Zn和Cu等元素.从组织和血中这些元素的含量来考虑,唯有Cd对硒中毒的影响值得注意.     

硒的人体最大安全摄入量研究 三、恩施高硒点居民血和发中某些拮抗金属元素的含量

恩施高硒区的硒来源于煤。煤中除硒外,尚有高含量的氟。此外,本地尚分布有丰富的硫铁矿,居民用作生产硫磺。由于环境污染严重,因此在观察硒的毒性时,应考虑其它有关元素的含量。本文测定了居民发中的Cd,Hg,As以及全血中的Cd,Zn和Cu等元素。从组织和血中这些元素的含量来考虑,唯有Cd对硒中毒的影响值得注意。