Differential responses to selenomethionine supplementation by sex and genotype in healthy adults

A year-long intervention trial was conducted to characterise the responses of multiple biomarkers of Se status in healthy American adults to supplemental selenomethionine (SeMet) and to identify factors affecting those responses. A total of 261 men and women were randomised to four doses of Se (0, 50, 100 or 200 μg/d as L-SeMet) for 12 months. Responses of several biomarkers of Se status (plasma Se, serum selenoprotein P (SEPP1), plasma glutathione peroxidase activity (GPX3), buccal cell Se, urinary Se) were determined relative to genotype of four selenoproteins (GPX1, GPX3, SEPP1, selenoprotein 15), dietary Se intake and parameters of single-carbon metabolism. Results showed that supplemental SeMet did not affect GPX3 activity or SEPP1 concentration, but produced significant, dose-dependent increases in the Se contents of plasma, urine and buccal cells, each of which plateaued by 9-12 months and was linearly related to effective Se dose (μg/d per kg0·75). The increase in urinary Se excretion was greater for women than men, and for individuals of the GPX1 679 T/T genotype than for those of the GPX1 679 C/C genotype. It is concluded that the most responsive Se-biomarkers in this non-deficient cohort were those related to body Se pools: plasma, buccal cell and urinary Se concentrations. Changes in plasma Se resulted from increases in its non-specific component and were affected by both sex and GPX1 genotype. In a cohort of relatively high Se status, the Se intake (as SeMet) required to support plasma Se concentration at a target level (Se(pl-target)) is: Se(in) = [(Se(pl - target) - Se(pl))/(18.2ng d kg?.??/ml per mu g)] .     

中国成人硒需要量研究

目的 探讨使人体血浆硒蛋白P(SEPPI)达到饱和的硒摄入量,以评估硒需要量,为膳食硒参考摄入量DRIB的修订提供参考.方法 时98名低硒健康受试者(体重平均58kg)进行为期40w的双盲补硒实验.随机分为七组,补硒(以硒蛋氨酸形式)剂量分别为0、21、35、55、79、102和125 μg/d.定期检测血浆中谷胱甘肽...     

硒代蛋氨酸对肝细胞L02中硒蛋白表达的影响及丝氨酸的协同作用

目的观察硒代蛋氨酸对肝细胞L02硒蛋白表达的影响及丝氨酸的协同作用。方法培养L02细胞,分为硒代蛋氨酸组和丝氨酸+硒代蛋氨酸组。硒代蛋氨酸剂量设为0.001、0.01、0.1、1和10μmol/L,丝氨酸和硒代蛋氨酸按照2∶1摩尔比混合。作用于L02细胞48 h后,采用酶联免疫吸附试验(enzyme-linked immuno-sorbent assay,ELISA)双抗体夹心法检测细胞培养上清液中硒蛋白P和裂解液中谷胱甘肽过氧化物酶1(glutathione peroxidase 1,GPx1)浓度,采用免疫印迹法检测裂解液中硒蛋白P和GPx1表达水平。结果硒代蛋氨酸浓度为0.1和1μmol/L时,硒蛋白P和GPx1表达分别达到拐点,硒代蛋氨酸浓度为10μmol/L时,GPx1和硒蛋白P表达下降。硒代蛋氨酸剂量为0.001~10μmol/L时,丝氨酸对细胞内GPx1和硒蛋白P表达具有协同作用。结论硒代蛋氨酸作用于人正常肝细胞L02时,硒蛋白合成出现拐点,且丝氨酸对硒代蛋氨酸在肝细胞L02内表达GPx1和硒蛋白P具有协同作用。     

Serum selenium levels in cirrhotic patients are not influenced by the disease severity index

Selenium (Se) is an antioxidant element that protects against cellular damage by reactive oxygen species. Therefore, total serum Se concentration may reflect protection during the development of cirrhosis, an oxidative stress-related disease. We hypothesized that serum Se levels are diminished in cirrhotic patients due to their enhanced oxidative stress, and serum Se levels are reduced the most in patients with the highest severity of cirrhosis. A case-control study was performed to determine whether cirrhosis is associated with changes in serum Se levels. Blood samples from 30 healthy controls and 93 cirrhotic patients were analyzed for total serum Se by hydride generation atomic absorption spectrometry. The Child-Pugh index score was used to evaluate the severity of liver disease. The mean serum Se concentration was significantly lower in patients vs controls (0.721 ± 0.239 vs 0.926 ± 0.241 μmol/L; P = .001). Mean serum Se levels were not significantly lower in patients with higher severity of cirrhosis (0.691 ± 0.229 vs 0.755 ± 0.255 μmol/L; P = .144). A positive and significant correlation was found between age and serum Se levels in patients (r = 0.277, P = .007). Patients showed significant sex differences in serum Se level (higher in male) and severity index (higher in female). The significantly decreased serum Se level in patients indicates that the Se component of the antioxidant system is severely impaired in cirrhosis. However, serum Se levels were not influenced by the severity of the disease.     

Tissue levels of mercury determined in a deceased worker after occupational exposure

Objectives: To examine mercury (Hg) and selenium (Se) levels in autopsy samples from a thermometer worker who had been exposed over a long period to, and monitored for, mercury vapor. Case report: Hg and Se levels were determined using radiochemical neutron activation analysis in a worker who had commited suicide 4 weeks after the end of 14 years of exposure and in an unexposed age-matched referent. Histochemical staining of cerebellum was performed according to the method of Danscher and Schrøder. Results: The Hg concentrations (wet weight) were 25?μg/g in the kidney cortex, 1.2?μg/g in the liver, 0.72?μg/g in the lung, 0.025?μg/g in the testis, and 0.014–0.018?μg/g in the cerebellum (gray matter, dentate nucleus, and white matter). The Se level in the kidney cortex was high, 4.6?μg/g, whereas the concentration detected in the other tissue samples was normal. Light microscopy of the cerebellum was normal, and no histochemical staining for mercury was observed. Autopsy samples from the referent showed low Hg and Se levels consistent with other reports. Conclusions: The observed kidney-Hg, which was 50–100 times higher than that occurring in the general population, is in agreement with previous sparse data from ongoing occupational exposure. The high Se level detected in the kidney indicates coaccumulation with mercury. The low Hg concentration found in the cerebellum was unexpected, since some reports have shown much higher brain-Hg long after the cessation of exposure.     

血清硒水平与糖尿病关系的横断面研究

目的探讨血清硒水平与糖尿病的关系。方法采用原子吸收法检测体检人群的血硒水平。结果体检人群中,1 157名非糖尿病患者群的血硒平均水平为98.9μg/L,173名糖尿病患者的血硒水平为97.6μg/L,差异无统计学意义(P=0.578)。logistic回归分析显示,人群中3个较高血硒区间(85.8~95.9μg/L,96.0~107.9μg/L,≥108.0μg/L)相对于最低血硒区间(85.8μg/L)的糖尿病发病优势比,分别为1.00、0.72、0.96,差异无统计学意义(P0.05)。结论研究提示血硒水平为96.0~107.9μg/L时糖尿病的发病率较低,但血清硒水平与糖尿病关系尚需前瞻性队列研究的进一步证实。     

Human biomonitoring of polychlorinated biphenyls (PCBs) in plasma of former underground miners in Germany – A case-control study

Polychlorinated biphenyls (PCBs) are very persistent organic pollutants of severe environmental concern due to their toxic properties. Former underground miners might have been exposed to this substance group due to the widespread use of PCBs in hydraulic oils from the late 1960s to the mid 1980s. We have conducted a blinded case-control study in order to evaluate the possibility of retrospective exposure assessment of PCBs using human biomonitoring in former underground miners decades after the last possible exposure.We have identified n?=?34 male former underground miners and n?=?136 age-matched male control persons from the database of patients of our occupational outpatient clinic aged between 47.9 and 83.7?years ?at the time of sampling (June 2006–June 2016). These archived plasma samples have been blinded and analysed for 21 different PCB-congeners using a validated and quality controlled procedure using GC/MS (LOQ: 0.01?μg/L).Highly significant differences between cases and age-matched controls were only found for the PCB-congeners PCB 74 and PCB 114. The median (95th percentile) levels of PCB 74 in cases and controls were 0.126?μg/L plasma (0.899?μg/L plasma) vs. 0.058?μg/L plasma (0.368?μg/L plasma) and the 95th percentile levels for PCB 114 were 0.039?μg/L plasma vs. 0.017?μg/L plasma. Linear regression models revealed that this difference in plasma levels was unequivocally attributed to the underground mining activity. Thus, retrospective exposure assessment for underground miners by use of human biomonitoring seems feasible and further studies with a particular focus on this special group of workers should be performed.     

深圳市母乳中矿物质含量及重金属负荷水平研究

目的了解深圳市初产、顺产妇的乳汁中8种矿物质(钙、钾、钠、镁和微量元素锌、铁、硒、铜)含量和3种有毒元素(铅、砷、镉)负荷水平,以评估该地婴儿8种常量元素和微量元素的营养状况和3种有毒元素污染水平。方法于2007年7～10月采集在深圳生活5年以上20～35岁的初产妇产后3周～2月龄的母乳共60份,采用电感耦合等离子体质谱法及电感耦合等离子体发射光谱法测定母乳中的常量元素钙、钾、钠、镁和微量元素锌、铁、硒、铜及有毒元素铅、砷、镉的含量。结果所测母乳的8种矿物质和重金属中,常量元素钙、钾、钠、镁的平均含量分别是280.22、498.61、188.65和28.31mg/L,微量元素锌、铁、硒、铜的平均含量分别是2.29mg/L、358.88μg/L、8.28μg/L和339.16μg/L,铅的平均含量是2.13μg/L。砷和镉的含量均小于0.005μg/L。结论与国际原子能机构的标准及国内的一些地区调查结果比较,深圳地区母乳中常量元素钙、钾、钠、镁和锌、铁、铜7种矿物质的平均含量基本合理,砷、镉的污染水平低,但是存在微量元素硒的缺乏和重金属铅的污染。     

胃癌患者血清瘦互与营养状况的关系

目的探讨肥胖基因表达产物瘦素与胃癌病人营养状况的关系。方法采用放射免疫分析法测定86例胃癌病人血清瘦素含量,同时测定身高、体重、疾病分期、ECOG。体质指数(BMI)=体重(kg)/身高(m)２。营养正常的BMI范围为18.5～25;BMI<18.5为营养不良;BMI>25为肥胖。结果胃癌病人合并营养不良组的血清瘦素平均含量明显低于营养正常组或肥胖组。男性胃癌病人合并营养不良、营养正常及肥胖组血清瘦素水平分别为(2.41±1.59)μg/L、(4.80±3.21)μg/L、(9.16±2.81)μg/L;女性则分别为(5.53±3.06)μg/L、(8.94±4.78)μg/L、(20.58±9.48)μg/L。全组男性、女性胃癌病人的血清瘦素水平分别为(4.39±3.42)μg/L、(8.97±6.56)μg/L;女性均值高于男性一倍。胃癌病人的血清瘦素水平与BMI显著相关(男性r=0.538,P<0.05;女性r=0.785,P<0.05)。BMI正常的胃癌病人的血清瘦素与健康人无差异。结论血清瘦素含量可以反映胃癌病人的BMI变化和营养状况,且可作为判断胃癌病人营养状况的指标。     

Mineral Concentrations in Cow's Milk from the Canary Island

Concentrations of selenium (Se), iron (Fe), copper (Cu), zinc (Zn), sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) were determined in samples of raw and sterilized cow's milk. The following mean concentrations (and ranges) were recorded in raw cow's milk: Se (μg/L), 16.44 (6.8–28.6); Fe (mg/L), 0.515 (0.19–1.00); Cu (mg/L), 0.076 (0.03–0.16); Zn (mg/L), 4.41 (2.3–6.6); Na (mg/L), 534.1 (278–870); K (mg/L), 1424 (1035–1874); Ca (mg/L), 1653 (1196–2236); Mg (mg/L), 113.9 (71.5–159.4). The sterilized cow's milk showed mean concentrations of Fe (0.170 mg/L) and Zn (3.06 mg/L) significantly lower than the concentrations observed in raw cow's milk; however, the mean concentrations of Se (14.90 μg/L) and Cu (0.110 mg/L) were similar and significantly higher than in raw cow's milk, respectively. No significant differences for Na, K and Mg were observed between the mean concentrations in raw and sterilized cow's milk. An important contribution to the daily intake of Ca and K for Canarian people due to the consumption of cow's milk was observed. Moderate amounts of Mg and Na, and smaller amounts of Zn and Se are also supplied. Our data for the mineral concentrations in cow's milk were within normal intervals of concentration described in the literature. The concentrations of Fe, Cu, Na, K and Ca in raw cow's milk remained approximately constant during the 12 months sampled. In contrast, the Se, Mg and Zn concentrations varied significantly with the climatic season, presenting the lowest mean concentrations during autumn.     

Biomonitoring of metals and trace elements in urine of central Ethiopian populations

Biomonitoring of chemical concentrations in humans is important for detecting, monitoring, and addressing a wide range of health threats. However, it is virtually absent across many African nations, including Ethiopia. This study aims to determine urinary concentrations for metals and trace elements in populations living in the central Ethiopian Rift Valley. The region is unindustralized, rural, and characterized by unique geologic rifting and volcanic activities that have produced vast pyroclastic materials, forming its aquifer and fertile agricultural soils. Millions of people in the region rely on wells for drinking water and are engaged in cereal-based subsistence agriculture. We enrolled a total of 386 residents aged 10–50 years old (201 females and 185 males). The levels of 23 elements except F^─ were quantified in water and urine samples by ICP-MS. Mean concentrations of B, F^─, Ca, and Mg were measured in mg/L levels, while concentrations of Mo, Zn, Sr, Rb, and Li ranged between 100 and 700?μg/L. Mean concentrations between 5 and 15?μg/L were found for Ni, Cu, and Mn, while Ag, Be, Cd, Co, Pb, Sb, Th, TI, and U were all below 5?μg/L. Arsenic and Al had mean concentrations between 30 and 50?μg/L. Mean urinary concentrations of Ca, Cu, Mg, Pb, Sr, and Zn were significantly higher in males than females, whereas Co and Mn were higher in females. Finally, younger individuals (10–30 years) had significantly higher mean concentrations of B, Cd, Co, Mg, Mo, and Pb than those between 31 and 50 years, whereas only Ca was higher in the older age group. The concentration ranges of B, Mo, Mn, TI, Li, Zn, and in particular F^─ (0.44–44.6?mg/L) and As (2.2–164?μg/L) in urine were higher than the reference ranges reported in healthy unexposed North American and European populations, while those for the remaining 16 elements were comparable to published reference ranges from such settings. The established concentration ranges are important to monitor future changes in exposure, and risk factors for disease, that might stem from the economic growth and industrialization that is currently underway in the region.     

A critical body residue approach for predicting persistent bioaccumulative toxicant effects on reproduction and population dynamics of meiobenthic copepods

Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose-response on a dry-weight or lipid-normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E-2317-14) produced biomass sufficient for dry mass and lipid-normalized CBR estimates of reproduction (fertility) and population growth suppression. Significant FS toxic effects were delayed naupliar development (at ≥0.10?μg?L(-1)), delayed copepodite development (at 0.85?μg?L(-1)), decreased reproductive success (at ≥ 0.39?μg?L(-1)), and decreased offspring production (at 0.85?μg?L(-1)). A reproductive median effective concentration (EC50) of 0.16?μg?L(-1) (95% CI: 0.12-0.21?μg?L(-1)) corresponded to an adult all-sex CBR and lipid-normalized CBR of 0.38?pg FS?·?μg(-1) dry weight (95% CI: 0.27-0.52?pg FS?·?μg(-1)) or 2.8?pg FS?·?μg(-1) lipid (95% CI: 2.2-3.6?pg FS?·?μg(-1)), respectively. Copepod log bioconcentration factor (BCF)?=?4.11?±?0.2. Leslie matrix projections regressed against internal dose predicted fewer than five gravid females in a population by the third generation at 0.39 and 0.85?μg FS?·?L(-1) (i.e., 9.6-10.2?μg FS?·?μg(-1) lipid), and 50% population suppression at a CBR of 1.6?pg FS?·?μg(-1) lipid. This more integrative population CBR as a management tool would fall 1.75 times below the CBR for the single most sensitive endpoint-fertility rate.     

Phytochemical profiles and antioxidant activity of 27 cultivars of tea

Tea, rich in phytochemicals, has been suggested to have human health benefits. The phenolic profiles, antioxidant and antiproliferative activities of 27 tea cultivars were determined. Wide ranges of variation were found in analyzed cultivars for the contents of water-soluble phenolics (121.6–223.7?mg/g dry weight (DW)), total catechins (TC) (90.5–177.2?mg/g DW), antioxidant activities (PSC values 627.3–2332.3?μmol of vitamin C equiv/g DW, ORAC values (1865.1–3489.3?μmol of vitamin C equiv/g DW), CAA values (37.7–134.3?μmol of QE/g DW without PBS wash and 25.3–75.4?μmol of QE/g DW with PBS wash) and antiproliferative activity (53.0–90.8% at the concentration of 400?μg/mL extracts). The PSC, ORAC and CAA values were significantly correlated with phenolics, epicatechin gallate (ECG), CC and TC. Knowledge of specific differences among tea cultivars is important for breeding tea cultivars and gives sights to its potential application to promote health.     

Determination of Bioaccumulation of Heavy Metals and Selenium in Tissues of Brown Trout Salmo trutta macrostigma (Duméril, 1858) from Munzur Stream, Tunceli, Turkey

The objective of the present work was to determine the bioaccumulation of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), uranium (U) and selenium (Se) in gill, liver, and muscle tissues of the fresh water fish Salmo trutta macrostigma (Duméril, 1858) in Munzur Stream, Tunceli, Turkey. The highest concentrations of U (1.83?μg?kg^?1), Pb (119.84?μg?kg^?1) and Se (1.31?μg?kg^?1) were recorded in the gills of S. t. macrostigma. Concentrations of As (46.27?μg?kg^?1), Cd (109.19?μg?kg^?1), Hg (16.40?μg?kg^?1), Cu (18.19?μg?kg^?1) were recorded at highest levels in the liver. The results showed that there were significant differences in concentrations of As, Cd, Cu, Pb, Se, U and Hg in gill, liver and muscle tissue (p?<?0.05). Heavy metals were within the edible parts of the investigated fish were in the permissible safety levels for human uses.     

微波消解-电感耦合等离子体质谱法测定小麦中的8种元素

目的利用微波消解-电感耦合等离子体质谱法测定小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的含量。方法样品经过微波消解后,用ICP-MS法同时测定小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的含量,以45 Sc、72Ge、103Rh、209Bi作为内标元素采用电感耦合等离子体质谱法测定,用标准曲线法进行定量。结果小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的回收率在95.6%~106.8%,线性相关系数(r)≥0.9995,Pb、Cd、As、Cr、Se、Ni、Al、Cu的检出限分别为0.0049μg/L、0.0023μg/L、0.012μg/L、0.016μg/L、0.026μg/L、0.0099μg/L、0.0070μg/L、0.0027μg/L;生物成分分析标准物质(小麦)的各元素的测定结果均在标准值不确定度范围内;同时对3份小麦样品进行连续6次测定,各元素的相对标准偏差(RSD)≤5%。结论本法线性范围宽、抗干扰能力强、测定周期短,完全满足分析的要求,适用于日常样品的检测。     

Factors associated with the blood and urinary selenium concentrations in the Canadian population: Results of the Canadian Health Measures Survey (2007–2011)

Objective

The objective of the present work is to assess the factors associated with whole blood and urinary selenium (Se) concentrations in Canadians aged 6–79 years old, and to interpret the data in the context of exposure guidance values.

Ion-release kinetics and ecotoxicity effects of silver nanoparticles

The environmental toxicity associated with silver nanoparticles (AgNPs) has been a major focus in nanotoxicology. The Ag(+) released from AgNPs may affect ecotoxicity, although whether the major toxic effect is governed by Ag(+) ions or by AgNPs themselves is unclear. In the present study, we have examined the ecotoxicity of AgNPs in aquatic organisms, silver ion-release kinetics of AgNPs, and their relationship. The 48-h median effective concentration (EC50) values for Daphnia magna of powder-type AgNP suspensions were 0.75?μg/L (95% confidence interval [CI]?=?0.71-0.78) total Ag and 0.37?μg/L (95% CI?=?0.36-0.38) dissolved Ag. For sol-type AgNP suspension, the 48-h EC50 values for D. magna were 7.98?μg/L (95% CI?=?7.04-9.03) total Ag and 0.88?μg/L (95% CI?=?0.80-0.97) dissolved Ag. The EC50 values for the dissolved Ag of powder-type and sol-type AgNPs for D. magna showed similar results (0.37?μg/L and 0.88?μg/L) despite their differences of EC50 values in total Ag. We observed that the first-order rate constant (k) of Ag(+) ions released from AgNPs was 0.0734/h at 0.05?mg/L total Ag at 22°C within 6?h. The kinetic experiments and the toxicity test showed that 36% and 11% of sol-type AgNPs were converted to the Ag(+) ion form under oxidation conditions, respectively. Powder-type AgNPs showed 49% conversion rate of Ag(+) ion from AgNPs. We also confirmed that Ag(+) ion concentration in AgNP suspension reaches an equilibrium concentration after 48?h, which is an exposure time of the acute aquatic toxicity test.     

Selenite toxicity and mercury-selenium interactions in Juvenile Fish

Acute lethal toxicities of selenium and the effects of selenium on mercury accumulation were determined in freshwater fish species. Selenite concentrations required to produce 50% mortality were approximately 11 mg Se/L in northern pike (Esox lucius), 29 mg Se/L in white sucker (Catostomus commersoni), and 5 mg Se/L in yellow perch (Perca flavescens) after 75, 96, and 240 hr of exposure, respectively. Two approaches were used to determine effects of water-borne selenium on mercury concentrations in northern pike. In the first, a trend of reduced mercury contamination at a low selenium concentration (1 ug Se/L) with maintenance at control mercury contamination levels at a higher selenium concentration (100μg Se/L) was apparent. In the second, a similar response of decreased CH₃ ²⁰³Hg accumulation in muscle-skin at lower selenium concentrations (1 and 10μg Se/L), but maintenance at control accumulation levels at a higher selenium concentration (100μg Se/L) was observed. Results and knowledge requirements are discussed with emphasis on relevance to increasing deposition rates of these chemical elements to freshwater ecosystems and using selenium to treat mercury-contaminated aquatic systems.     

Depressed serum selenoprotein P: possible new predicator of increased risk for cerebrovascular events

Selenium protection against cellular damage by oxygen radicals is accomplished through selenoproteins. Thus, selenium protection during the development of stroke, an oxidative stress–related disease, may not be appropriately reflected in the total serum selenium concentration. Therefore, we hypothesized that serum selenoproteins should also be measured to understand the relationship between selenium status and oxidative stress. To establish whether stroke is associated with changes in serum selenoprotein levels, a population-based, nested case-control study was performed. The subjects were recruited from 1632 residents older than 40 years who had completed health examinations in 1992. Blood samples collected from 30 controls and 30 initial stroke victims between 1992 and 1994 were analyzed for total serum selenium and selenium-containing protein distribution. Selenium-containing proteins were separated using 2 high-performance liquid chromatography columns in tandem and detected by inductively coupled plasma–mass spectrometry. The mean serum selenium concentration was lower in the patients who had a stroke than in the controls (105.2 vs 116.5 μg/L). Selenium contents in glutathione peroxidase and albumin did not show any significant difference; however, selenoprotein P was significantly lower in the stroke cases than in the controls (54.5 vs 63.0 μg/L, P = .006). Results from multivariate logistic regression analysis showed that reduced serum level of selenoprotein P was associated with a higher risk of stroke (odds ratio = 0.28; 95% confidence interval, 0.10-0.85).     

正常妊娠妇女血清锌及发锌含量的研究

分别测定了8个地区2833例健康非孕及妊娠妇女血清锌、发锌的含量。结果表明,妊娠妇女整个孕期血锌含量平均下降23.8%,发锌下降49%。统计分析表明,血清锌、发锌与某些重要的血清生化指标呈显著正相关,血清锌与膳食锌、低体重儿出生率亦有一定关系。作者认为,孕妇血清锌、发锌含量是评价妊娠期锌营养状况的重要实验室指标,初步建议妊娠期妇女血清锌低限正常参考值为:早期9.18μmol/L、中期8.87μmol/L、晚期8.42μmol/L;发锌:早、中期为110μg/g、晚期为100μg/g。