Selenium level in the environment and the population of Zhoukoudian area, Beijing, China

Epigallocatechin gallate (EGCG) nanoselenium application improves tea quality (Camellia sinensis L.) and soil quality index without losing microbial diversity: A pot experiment under field condition

Applying selenium (Se) fertilizer is the only way to alleviate soil Se deficiency. Although effects of nanoselenium foliar application on plant growth and stress resistance have been extensively investigated, soil application of nanoselenium on soil microorganisms and their relationship with crop quality and soil health remains unclear. In this study, a steady-state homogeneous nanoparticle of epigallocatechin gallate Se (ESe) was synthesized, and a pot experiment was conducted applying ESe at five concentrations (0, 1, 10, 50, and 100 mg kg-1) to the tea planattion soil. The study revealed a significant increase in Se concentration in soil and tea with ESe application and identified 2.43-7.8 mg kg-1 as the safe and optimal range for soil application. Specifically, the moderate dose of ESe improved the tea quality [reduced tea polyphenols (TP), increased free amino acids (AA), and reduced TP/AA] and soil quality index (SQI). Besides, in marure tea leaves, antioxidant enzyme activities [promote catalase (CAT) superoxide dismutase (SOD), and peroxidase (POD)] increased, while level of oxidative stress [malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2-)] decreased with ESe application. The 16S rRNA of the soil bacteria showed that ESe application significantly changed the community structure of soil bacteria but did not alter the diversity of the bacteria and the abundance of dominant taxa (phylum and genus levels). Statistical analysis of the taxonomic and functional profiles (STAMP) detected 21 differential taxa (genus level), mainly low-abundance ones, under the ESe application. Linear regression and random forest (RF) modeling revealed that the low-abundance bacterial taxa were significantly correlated with SQI (R2 = 0.28, p < 0.01) and tea quality (R2 = 0.23-0.37, p < 0.01). Thus, the study's findings suggest that ESe application affects soil and tea quality by modulating the low-abundance taxa in soil. The study also highlights the crucial role of low-abundance bacterial taxa of the rhizosphere in regulating soil functions under the ESe application.

Selenium deficiency-induced multiple tissue damage with dysregulation of immune and redox homeostasis in broiler chicks under heat stress

Broiler chicks are fast-growing and susceptible to dietary selenium (Se) deficiency. This study sought to reveal the underlying mechanisms of how Se deficiency induces key organ dysfunctions in broilers. Day-old male chicks (n=6 cages/diet, 6 chicks/cage) were fed with a Se-deficient diet (Se-Def, 0.047 mg Se/kg) or the Se-Def+0.3 mg Se/kg (Control, 0.345 mg Se/kg) for 6 weeks. The serum, liver, pancreas, spleen, heart, and pectoral muscle of the broilers were collected at week 6 to assay for Se concentration, histopathology, serum metabolome, and tissue transcriptome. Compared with the Control group, Se deficiency induced growth retardation and histopathological lesions and reduced Se concentration in the five organs. Integrated transcriptomics and metabolomics analysis revealed that dysregulation of immune and redox homeostasis related biological processes and pathways contributed to Se deficiency-induced multiple tissue damage in the broilers. Meanwhile, four metabolites in the serum, daidzein, epinephrine, L-aspartic acid and 5-hydroxyindoleacetic acid, interacted with differentially expressed genes with antioxidative effects and immunity among all the five organs, which contributed to the metabolic diseases induced by Se deficiency. Overall, this study systematically elucidated the underlying molecular mechanisms in the pathogenesis of Se deficiency-related diseases, which provides a better understanding of the significance of Se-mediated heath in animals.

A pilot survey of selenium status and its geospatial variation among children and women in three rural districts of Zimbabwe

Introduction

Selenium (Se) deficiency is increasingly recognized as a public health problem in sub-Saharan Africa.

Methods

The current cross-sectional study assessed the prevalence and geospatial patterns of Se deficiency among children aged 6-59 months (n = 741) and women of 15-49 years old (n = 831) selected by simple random sampling in rural Zimbabwe (Murewa, Shamva, and Mutasa districts). Venous blood samples were collected and stored according to World Health Organization guidelines. Plasma Se concentration was determined by inductively coupled plasma-mass spectrometry.

Results

Median, Q1, and Q3 plasma Se concentrations were 61.2, 48.7, and 73.3 μg/L for women and 40.5, 31.3, and 49.5 μg/L for children, respectively. Low plasma Se concentrations (9.41 μg/L in children and 10.20 μg/L in women) indicative of severe Se deficiency risk was observed. Overall, 94.6% of children and 69.8% of women had sub-optimal Se status defined by plasma Se concentrations of <64.8 μg/L and <70 μg/L, respectively.

Discussion

High and widespread Se deficiency among women and children in the three districts is of public health concern and might be prevalent in other rural districts in Zimbabwe. Geostatistical analysis by conditional kriging showed a high risk of Se deficiency and that the Se status in women and children in Murewa, Shamva, and Mutasa districts was driven by short-range variations of up to ⁓12 km. Selenium status was homogenous within each district. However, there was substantial inter-district variation, indicative of marked spatial patterns if the sampling area is scaled up. A nationwide survey that explores the extent and spatial distribution of Se deficiency is warranted.

Maternal micronutrient disturbance as risks of offspring metabolic syndrome

Metabolic syndrome (MetS) is defined as a constellation of individual metabolic disturbances, including central obesity, hypertension, dyslipidemia, and insulin resistance. The established pathogenesis of MetS varies extensively with gender, age, ethnic background, and nutritional status. In terms of nutritional status, micronutrients are more likely to be discounted as essential components of required nutrition than macronutrients due to the small amount required. Numerous observational studies have shown that pregnant women frequently experience malnutrition, especially in developing and low-income countries, resulting in chronic MetS in the offspring due to the urgent and increasing demands for micronutrients during gestation and lactation. Over the past few decades, scientific developments have revolutionized our understanding of the association between balanced maternal micronutrients and MetS in the offspring. Examples of successful individual, dual, or multiple maternal micronutrient interventions on the offspring include iron for hypertension, selenium for type 2 diabetes, and a combination of folate and vitamin D for adiposity. In this review, we aim to elucidate the effects of maternal micronutrient intake on offspring metabolic homeostasis and discuss potential perspectives and challenges in the field of maternal micronutrient interventions.

Effects of organic and inorganic selenium on selenium bioavailability, growth performance, antioxidant status and meat quality of a local beef cattle in China

Selenium (Se) is an essential nutrient with multiple health benefits to humans and animals. Cattle generally require dietary Se supplementation to meet their daily requirements. The two main forms of dietary Se in cattle are organic Se and inorganic Se. Data comparing the health and productivity effects of organic Se and inorganic Se on cattle are still insufficient, and it is necessary to conduct more research to evaluate the bioavailability, nutritional value, deposition, and body functions of Se sources in different breeds and physiological stages of cattle raised in areas with different Se levels. The objectives of this study were to determine the effects of organic and inorganic sources of Se on plasma biochemical indices, Se bioavailability, deposition in body tissues and organs, growth performance, antioxidant capacity and meat quality of beef cattle raised in Se-deficient areas. Fifteen Chinese Xiangzhong Black beef cattle with an average weight of 254.5 ± 8.85 kg were assigned to three dietary groups. The three groups were fed the same basal ration and supplemented with either an inorganic [sodium selenite (SS)] or organic [selenomethionine (SM) or Se-enriched yeast (SY)] source of Se (0.1 mg/kg dry matter) for 60 days. At the end of the experiment, three cattle from each group were randomly selected and slaughtered, and samples were collected from tissues and organs for analysis. The results revealed that growth performance, slaughter performance, Se content of tissues and organs, meat quality characteristics including chemical composition, pH_45min, pH_24h, drip loss, and cooking losses did not differ (p > 0.05) due to supplementation of the different organic and inorganic sources of Se. SM and SY were more effective in increasing (p < 0.05) immunoglobulin M (IgM) concentrations in the blood and reducing (p < 0.05) malondialdehyde (MDA) content in the longissimus dorsi than SS. In conclusion, organic Se is more effective than inorganic Se in improving the immune and antioxidant capacity of Chinese Xiangzhong Black beef cattle.

Selenium Deficiency Dysregulates One-Carbon Metabolism in Nutritional Muscular Dystrophy of Chicks

BACKGROUND

Nutritional muscular dystrophy (NMD) in animals is induced by dietary selenium (Se) deficiency.

OBJECTIVES

This study was conducted to explore the underlying mechanism of Se deficiency-induced NMD in broilers.

METHODS

One-day-old male Cobb broilers (n = 6 cages/diet, 6 birds/cage) were fed a Se-deficient diet (Se-Def, 47 μg Se/kg) or the Se-Def supplemented with 0.3 mg Se/kg (control) for 6 wk. Thigh muscles of broilers were collected at week 6 for measuring Se concentration, histopathology, and transcriptome and metabolome assays. The transcriptome and metabolome data were analyzed with bioinformatics tools and other data were analyzed with Student's t tests.

RESULTS

Compared with the control, Se-Def induced NMD in broilers, including reduced (P < 0.05) final body weight (30.7%) and thigh muscle size, reduced number and cross-sectional area of fibers, and loose organization of muscle fibers. Compared with the control, Se-Def decreased (P < 0.05) the Se concentration in the thigh muscle by 52.4%. It also downregulated (P < 0.05) GPX1, SELENOW, TXNRD1-3, DIO1, SELENOF, H, I, K, M, and U by 23.4-80.3% in the thigh muscle compared with the control. Multi-omics analyses indicated that the levels of 320 transcripts and 33 metabolites were significantly altered (P < 0.05) in response to dietary Se deficiency. Integrated transcriptomics and metabolomics analysis revealed that one-carbon metabolism, including the folate and methionine cycle, was primarily dysregulated by Se deficiency in the thigh muscles of broilers.

CONCLUSIONS

Dietary Se deficiency induced NMD in broiler chicks, potentially with the dysregulation of one-carbon metabolism. These findings may provide novel treatment strategies for muscle disease.

Association between plasma selenium and risk of ischemic stroke: A community-based, nested, and case-control study

Background

The prospective association between plasma Se and stroke risk remains inconclusive. The relationship between Se and ischemic stroke among a low circulating Se status population deserves more attention, especially for Chinese people who were a high-risk group for Se deficiency.

Objective

The relationship between plasma Se concentration and ischemic stroke risk in a large-scale Chinese community-based population and any potential effect modifiers were investigated.

Methods

A nested, case-control study, using data from the “China H-type Hypertension Registry Study” were conducted. A total of 1,904 first ischemic stroke cases and 1,904 controls matched for age, sex, and village were included in this study. The association between plasma Se and first ischemic stroke was evaluated by conditional logistic regression analyses.

Results

The median value of plasma Se was 65.8 μg/L among total participants. Overall, a significant inverse relationship between plasma Se and first ischemic stroke risk was found (per SD increment; adjusted OR: 0.87; 95% CI: 0.80 and 0.95). Accordingly, a significantly lower risk of first ischemic stroke was found in participants in quartile 3 (65.8−&lt;77.8 μg/L) (adjusted OR: 0.78; 95% CI: 0.63 and 0.96) and quartile 4 (≥77.8 μg/L) (adjusted OR: 0.76; 95% CI: 0.59 and 0.96), compared with those in quartile 1 (&lt;56.0 μg/L). Furthermore, a significantly lower ischemic stroke risk was found in those with lower low-density lipoprotein cholesterol (LDL-C) levels (&lt;3.4 vs. ≥3.4 mmol/L; P for interaction = 0.015) or those with lower homocysteine levels (&lt;12.1 (median) vs. ≥12.1 μmol/L; P for interaction = 0.027) at baseline.

Conclusion

Plasma Se was significantly inversely associated with the risk of first ischemic stroke among a large-scale Chinese community-based population (most adults with hypertension and elevated total homocysteine), especially among those with lower LDL-C and lower homocysteine levels.

Environmental effects on trace elements in the fingernails of centenarians and their offspring

Bio-monitoring is commonly used to investigate trace elements, and the human nail provides an ideal medium for such testing. Toxic and essential trace metals (Cd, Pb, Fe, and Se) in the fingernails of participants from the Hainan Province were investigated. Samples included 136 centenarians and 197 offspring (101 older adult children and 96 middle-aged grandchildren) who were also sampled for comparison. As a hotspot for longevity, participants in the Hainan Province were found to have high essential nutrients of Fe and Se, and lacked the toxic element Pb. A similar trend was found for trace elements in soil and rice in the Hainan Province. The trace elements preserved in nails revealed dietary and environmental influences that varied among different generations. For the grandchildren's generation, the environment played an important role in elements in their nails, and a significant correlation and linear relationships were found, especially for Fe and Se. As the participants increased in age (from the grandchildren to the centenarians), the correlation between various elements decreased. For centenarians, the influence of beneficial or harmful properties of the elements became more important than their environment. The results also pointed to the important role of trace elements in human health, especially Fe and Se as essential elements. This study can provide information on the factors that influence the existence of trace elements in the human body and demonstrate the advantage of using the human fingernail in bio-monitoring.

Hair Selenium of Residents in Keshan Disease Endemic and Non-endemic Regions in China

Few nationwide investigations on hair selenium (Se) and Keshan disease (KD) have been conducted. KD is closely associated with Se deficiency. Hair Se is an important biomarker for selenium nutrition. This research aimed to provide evidence for assessment of KD prevention, control, and elimination at the molecular level from the etiological perspective of selenium nutrition. The hair Se of the residents living in the KD endemic and non-endemic areas were determined through atomic fluorescence spectrometer. The median of the hair Se levels of the inhabitants living in KD endemic counties was significantly lower than that in KD non-endemic counties (0.34 vs 0.39 mg/kg, U = -10.03, P < 0.0001). The proportion of Se-deficient or Se-marginal residents in KD endemic counties was significantly higher than that in KD non-endemic counties (56.9% vs 36.6%, U = -9.57, P < 0.0001). The medians of the hair Se levels in KD endemic provinces of Shannxi, Heilongjiang, and Gansu were the lowest (0.35mg/kg), and in the category of Se-marginal status. The hair Se level featured a positive Spearman correlation with per capita disposable income (r_s = 0.20, P < 0.0001). In conclusion, the median of the hair Se contents of residents living in KD endemic counties was significantly lower than that in KD non-endemic counties. The hair Se contents of nearly 57% of inhabitants living in KD endemic regions were in Se-deficient or Se-marginal status. The KD endemic provinces of Shannxi, Heilongjiang, and Gansu should be given high priority in KD prevention and control.

Arbuscular Mycorrhizal Fungal Inoculation Increases Organic Selenium Accumulation in Soybean (Glycine max (Linn.) Merr.) Growing in Selenite-Spiked Soils

Selenium (Se) is an essential trace element for humans. Arbuscular mycorrhizal fungi (AMF) play a crucial role in increasing plant micronutrient acquisition. Soybean (Glycine max (Linn.) Merr.) is a staple food for most people around the world and a source of Se. Therefore, it is necessary to study the mechanism of Se intake in soybean under the influence of AMF. In this study, the effects of fertilization with selenite and inoculation with different AMF strains (Claroideoglomus etunicatum (Ce), Funneliformis mosseae (Fm)) on the accumulation and speciation of Se in common soybean plants were discussed. We carried out a pot experiment at the soil for 90 days to investigate the impact of fertilization with selenite and inoculation with Ce and Fm on the Se fractions in soil, soybean biomass, accumulation and speciation of Se in common soybean plants. The daily dietary intake of the Se (DDI) formula was used to estimate the risk threshold of human intake of Se from soybean seeds. The results showed that combined use of both AMF and Se fertilizer could boost total Se and organic Se amounts in soyabean seeds than that of single Se application and that it could increase the proportion of available Se in soil. Soybean inoculated with Fm and grown in soil fertilized with selenite had the highest organic Se. The results suggest that AMF inoculation could promote root growth, more soil water-soluble Se and higher Se uptake. The maximum Se intake of soybean for adults was 93.15 μg/d when treated with Se fertilizer and Fm, which satisfies the needs of Se intake recommended by the WHO. Combined use of AMF inoculation and Se fertilizer increases the bioavailable Se in soil and promotes the total Se concentration and organic Se accumulation in soybean. In conclusion, AMF inoculation combined with Se fertilization can be a promising strategy for Se biofortification in soybean.

Combined exogenous selenium and biochemical fulvic acid reduce Cd accumulation in rice

Paddy soil Cd contamination and the related accumulation risk in rice grains have attracted global attention. The application of selenium and humic substances is considered to be a cost-effective Cd mitigation measure. However, the effect of a combined application of the two materials remains unclear. Therefore, a 2-season pot experiment was conducted, wherein sodium selenite (Se) and biochemical fulvic acid (BFA) were applied alone and together. Paddy soils with two levels of Cd contamination were used. The results indicate that Se application alone considerably decreased the rice grain Cd content by 36.1-48.7% compared to the control rice grain Cd concentration, which was above the food safety limit (0.2 mg kg^-1). Although the application of BFA alone decreased the soil pH, it also increased the soil CaCl₂ extractable Cd content by 0.2 to 19.3% and had a limited effect on Cd in the rice grains. The combined application of Se and BFA did not affect the soil pH or the CaCl₂ extractable Cd, and more effectively reduced the Cd contents of the rice grains by 50.2 to 57.1%, except for the control rice grain Cd content, which was below the limit. The combined application of Se and BFA also inhibited Se accumulation in rice grains, maintaining the Se content at a safe level (0.33-0.58 mg kg^-1) compared to Se application alone. The effects of reducing the Cd content of rice grains while safely increasing their Se contents could persist for at least two seasons. Therefore, the combined application of Se and BFA should be recommended to mitigate Cd contamination risks in Cd-contaminated paddy soil.

A Cross-Sectional Study of the Distribution Patterns and Potential Determinants in Plasma Selenium Status Among Chinese Adults With Hypertension

Selenium (Se) is an essential trace element in selenoproteins biosynthesis for the human body and plays an important role in the prevention and control of subsequent cardiovascular disease in adults with hypertension. However, reports on Se status and its potential determinants in populations from different regions of China are limited, especially data on adults with hypertension, a high-risk group more vulnerable to oxidative stress. Thus, we conducted a cross-sectional study from February 2017 to May 2018 of 2,599 participants (1,389 men and 1,210 women) on middle-aged to elderly adults with hypertension with a mean age of 63.1 years (SD 13.3) from 14 provinces of China and aimed to examine the relationship of plasma Se status with demographic characteristics and lifestyles. Overall, the male participants (mean value 75.0 μg/L) tended to have higher plasma Se concentrations than the female participants (73.7 μg/L) when controlling for relevant factors. There were significant differences among regions, and in age and body mass index (BMI) in plasma Se distribution, and plasma Se concentrations were significantly lower among those in the regions with relatively lower Se, aged 60 years or older, and with BMI lower than 28 kg/m². Moreover, a higher frequency of meat consumption (1-2 or ≥3 times/week vs. <1 time/week) was significantly associated with higher plasma Se concentrations in men and women, and male alcohol drinkers had significantly higher plasma Se concentrations than non-alcohol drinkers. Adequate consumption of fruits and vegetables (0.5-1.5 kg/week) was associated with higher plasma Se concentrations among women, but was associated with relatively lower plasma Se concentrations in men. Our results indicated relatively low plasma Se status in Chinese adults with hypertension from 14 provinces, while specific factors including geographic, demographic, and lifestyle characteristics and blood pressure were significantly associated with plasma Se status in this hypertensive population. In addition, more studies are required to further evaluate dietary structure and other lifestyle factors that influence circulating Se status.

Reference Ranges of Selenium in Plasma and Whole Blood for Child-Bearing-Aged Women in China

Selenium (Se) is a "dual-surface" element. Both Se-deficiency and Se-overload have bad effects on humans. The amount of Se in the blood is a good indicator of Se intake, and there are considerable differences in the reference ranges among different regions and populations. The purpose of this study was to establish the age-specific reference interval of blood Se in healthy child-bearing-aged women in China. A total of 187 healthy women aged 18-45 years old were enrolled with strict inclusion criteria from the China Adult Chronic Disease and Nutrition Surveillance (2015 CACDNS) database to establish the reference interval of Se. Plasma and whole-blood Se were detected by inductively coupled plasma mass spectrometry (ICP-MS). The reference range (RR) estimated as P2.5-P97.5 percentiles (geometric mean) was 73.81-140.75 (100.94) μg/L and P2.5-P97.5 percentiles (median) 81.06-164.75 (121.05) μg/L for plasma and whole-blood Se, respectively. The proposed RR of plasma Se in this study was used to evaluate the Se nutritional status of a representative sample of 1950 women of child-bearing age who were randomly selected from 2015 CACDNS. The proportion of Se level lower than P2.5 cut-off value was 24.05%, and there were 5.08% child-bearing-aged women with plasma Se higher than the upper limit of RR. Women in the western and rural areas tend to have lower Se levels.

Marketing Healthy Diets: The Impact of Health Consciousness on Chinese Consumers’ Food Choices

Dietary choices, as the types and amounts of foods that individuals consume, are a major determinant of human health and environmental sustainability. From a marketing perspective, it becomes imperative to identify and understand the factors that motivate consumers to adopt a sustainable diet and purchase healthy food. This research is an attempt to contribute to the literature by revealing the major driving forces leading to healthy food consumption and identifying its underlying mechanism. Based on a survey of the diets and lifestyles of 307 Chinese consumers in several cities of the Jiangxi and Guangdong provinces, our empirical results indicate that consumer health consciousness is a major predictor of the intention to purchase healthy products. Such a relationship is explained by the psychological benefits associated with the consumption experience and the perceived naturalness of the product. Moreover, a high perceived nutritional value will enhance the mediation influences of the psychological benefit and the perceived naturalness on purchase intention while a low perceived nutritional value tends to negate such an impact.

The role of selenium in depression: a systematic review and meta-analysis of human observational and interventional studies

The results of human studies are inconsistent regarding selenium and depressive disorders. Therefore, we aimed to conduct a systematic review and meta-analysis of observational and interventional studies and provided an overview of the role of selenium in depression. Three databases including Medline, Scopus, and Web of Science were searched on June 30, 2020 and updated on April 12, 2021. Also, we searched in electronical databases of WHO Global Index Medicus and ClinicalTrials.gov. No time or language restrictions were used for the search. A random effects model was used to pool effect sizes. In total, 20 studies were included in the systematic review, and 15 studies were included in the meta-analysis. There were no significant differences in serum selenium levels between patients with depression and healthy subjects (WMD: 2.12 mg/L; 95% CI: - 0.11, 4.36; I2 = 98.0%, P < 0.001). Also, no significant correlation was found between serum levels of selenium and depression scores (r: - 0.12; 95% CI: - 0.33, 0.08; I2 = 73.5%, P = 0.010). Nevertheless, there was a significant negative association between high selenium intake and the risk of postpartum depression (OR: 0.97; 95% CI: 0.95, 0.99; I2 = 0.0%, P = 0.507). In addition, selenium supplementation significantly reduced depressive symptoms (WMD: - 0.37; 95% CI: - 0.56, - 0.18; I2 = 0.0%, P = 0.959). Taken these results together, selenium seems to have a protective role against postpartum depression and can be considered as a beneficial adjuvant therapy in patients with depression. Further studies are necessary to draw definitive conclusions.

Plasma selenium and the risk of first stroke in adults with hypertension: a secondary analysis of the China Stroke Primary Prevention Trial

BACKGROUND

Previous studies have indicated that selenium (Se) may play an important role in cardio-cerebrovascular disease. However, the relation between circulating selenium and risk of first stroke remains inconclusive.

OBJECTIVES

We conducted a secondary analysis of the China Stroke Primary Prevention Trial (CSPPT), using a nested case-control design, and aimed to investigate the correlation between Se concentration and first stroke risk in adults with hypertension and examine the potential effect modifiers.

METHODS

In the CSPPT, a total of 20,702 adults with hypertension were randomly assigned to a double-blind daily treatment with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. A total of 618 first stroke cases and 618 controls matched for age, sex, treatment group, and study site were included in this study.

RESULTS

During a median follow-up duration of 4.5 y (IQR: 4.2-4.6 y), there was a significant inverse association between plasma Se and the risk of first stroke (per SD increment; adjusted OR: 0.81; 95% CI: 0.68, 0.96) and ischemic stroke (per SD increment; adjusted OR: 0.76; 95% CI: 0.62, 0.93). Furthermore, a stronger inverse association between plasma Se and first stroke was observed in participants with higher folate concentrations at baseline [≥7.7 ng/mL (median), adjusted OR: 0.67; 95% CI: 0.54, 0.85, compared with <7.7 ng/mL, adjusted OR: 0.98; 95% CI: 0.80, 1.21; P-interaction = 0.008] and those with higher time-averaged systolic blood pressure (SBP) over the treatment period (≥140 mm Hg, adjusted OR: 0.71; 95% CI: 0.58, 0.86, compared with <140 mm Hg, adjusted OR: 0.96; 95% CI: 0.77, 1.20; P-interaction = 0.023).

CONCLUSIONS

There was a significant inverse association between plasma Se and risk of first stroke in Chinese adults with hypertension, especially among those with higher baseline folate concentrations and those with higher time-averaged SBP over the treatment period. This trial was registered at clinicaltrials.gov as NCT00794885.

Effect of foliar application of the selenium-rich nutrient solution on the selenium accumulation in grains of Foxtail millet (Zhangzagu 10)

The foliar application of selenium (Se) is an effective method for biofortification of Se in crop grains in order to provide sufficient Se for human health. As a staple food in China, the foxtail millet (Setaria italica L.), which had been Se biofortification, would be helpful to overcome Se deficiency in the diet. The Se fertilizer and its application technology are vital for reducing environmental risk while enriching selenium. Hence, the Se-rich nutrient solution developed by ourselves was used, and the effect of its amount and growth stage applied on the accumulation of Se in grains of foxtail millet (Setaria italica L.) was studied in the present study. The results were as follows: (1) the Se concentration in grains increased with the Se application rate increasing, and the highest Se concentration in grains was 1.83 mg kg^-1 at the sprayed concentration of 61.5 gSe hm^-2; (2) the accumulation of Se sprayed in the grain-filling stage was 1.3-1.6 times higher than that in the joint stage; and (3) the organ damage could be found under low Se/S ratio, which happened in the rice leaves when the Se rate was higher than 76.875 gSe m^-2 with the low sulfate application compared with the formulation. This Se-rich nutrient solution could be used to produce the Se-rich millet grains and foliar application in the reproductive stage to produce qualified Se-rich millet.

Associations between urinary heavy metal concentrations and blood pressure in residents of Asian countries

BACKGROUND

Previous studies have suggested that exposures to heavy metals (arsenic, cadmium, lead, and selenium) may be associated with differences in blood pressure. However, the findings of these studies have been inconsistent. This study was performed to examine the associations between urinary heavy metal concentrations and blood pressure among residents of four Asian countries (Bangladesh, Indonesia, Nepal, and Vietnam).

METHODS

This cross-sectional study examined 1899 adults in four Asian countries. Urinary concentrations of heavy metals were measured by inductively coupled plasma mass spectrometry. A questionnaire survey was administered regarding individual characteristics. Anthropometric measurements (height and weight) were performed. Systolic and diastolic blood pressures were measured after a short rest. Multiple linear regression models were applied to investigate associations between urinary heavy metal concentrations and blood pressure after adjustments for age, sex, and body mass index.

RESULTS

The geometric means of the urinary concentrations of arsenic, cadmium, lead, and selenium were 84.6, 0.885, 2.09, and 16.5 μg/g creatinine, respectively. The urinary arsenic concentrations were slightly higher than those typically reported in non-polluted populations, while urinary cadmium, lead, and selenium concentrations were equivalent or slightly lower. The urinary lead concentrations were positively associated with both systolic and diastolic blood pressure, but urinary selenium concentrations were negatively associated with them.

CONCLUSIONS

Variations in the urinary concentrations of lead and selenium were associated with blood pressure at low levels of exposure/intake.

Biogenic Selenium Nanoparticles: Potential Solution to Oxidative Stress Mediated Inflammation in Rheumatoid Arthritis and Associated Complications

Rheumatoid arthritis (RA) is a common chronic inflammation-mediated disorder having systematic complications. RA triggers a self-directed inflammatory and immunological cascade that culminates in joint destruction. Though a range of treatment options are available, none of them are without adverse effects and this has led researchers to search for alternative solutions. Nanomedicine has emerged as a powerful therapeutic alternative, and selenium (Se) is an essential micronutrient trace element that has a crucial role in human health and disease. Selenium nanoparticles (SeNPs) derived from biological sources, such as plants, bacteria, fungi, and proteins, have exhibited remarkable candidate properties and toxicological profiles, and hence have shown potential to be used as antirheumatic agents. The potential of SeNPs can be attributed to the effect of functional groups bound to them, concentration, and most importantly to their nano range size. The antirheumatic effect of SeNPs is considerable due to its potential in amelioration of oxidative stress-mediated inflammation via downregulation of radical and nonradical species, markers of inflammation, and upregulation of inherent antioxidant defenses. The size and concentration impact of SeNPs has been shown in the subsequent antioxidant and anti-inflammatory properties. Moreover, the article emphasizes the role of these biogenic SeNPs as a notable option in the nanomedicine arena that needs to be further studied as a prospective remedial alternative to cure RA and medication-related adverse events.

Exogenous selenium (cadmium) inhibits the absorption and transportation of cadmium (selenium) in rice

Antagonism between selenium (Se) and cadmium (Cd) has been demonstrated in plants. However, a mutual suppression threshold for Se and Cd has not been identified in previous studies using Cd or Se individually. To fill this knowledge gap, we determined the levels of Se and Cd in various tissues of rice under concentration gradients of Se and Cd with different Se application times via hydroponic experiments. The results showed that the application of exogenous Se or Cd reduced the uptake and transport of the other. When the molar ratio of Se/Cd (R (Se/Cd)) was higher than 1, the concentration and transfer factor of Cd (TF-Cd) in all parts of rice simultaneously reached the lowest values. The minimum Se absorption in rice was obtained at R (Cd/Se) greater than 20, while no inhibition threshold was found for Se transport. In addition, approximately 1:1 R (Se/Cd) was observed in roots and the addition of exogenous Cd or Se promoted the enrichment of the other element in roots. These data suggested a mutual inhibition of Se and Cd in their absorption, transportation and accumulation in rice, which might be related to the formation of insoluble Cd-Se complexes in roots. This study provided new insights into a plausible explanation of the interactions between Se and Cd and contributed to the remediation and treatment of combined Se and Cd pollution in farmland systems.

Selenium Nutritional Status of Rural Residents and Its Correlation with Dietary Intake Patterns in a Typical Low-Selenium Area in China

China is recognized as a selenium-deficient country, and nutritional selenium intake has always been a concern. To clarify the current inhabitants’ selenium nutrition status and the characteristics of dietary consumption in low-selenium areas, samples of human hair and grains were collected, and food frequency questionnaires were administered in Binxian County, Shaanxi Province, a typical low-selenium area in the Loess Plateau. The subject number of the study is 85, and the age range is from 11 to 81 years, with an average of 60. The results showed that the average hair selenium content of the residents was 231.7 μg/kg, and 62.4% of the participants had levels higher than the selenium deficiency threshold (200 μg/kg). There was a significant positive correlation between the hair selenium content and the food consumption score after adjusting for rice outsourcing. Three different dietary patterns were noted according to hierarchical cluster analysis. This study provides a tool for assessing the selenium nutrition of inhabitants in low-selenium areas and has considerable significance for improving the dietary pattern of residents.

Preparation of Selenium-Enriched Yeast by Re-Using Discarded Saccharomyces cerevisiae from the Beer Industry for Se-Supplemented Fodder Applications

Both inorganic and organic selenium (Se) can prevent and treat various diseases caused by Se deficiency. However, organic Se has less toxicity and a higher absorption rate than inorganic Se. In this study, inorganic Se (Na2SeO3) was bio-transformed into Se-enriched discarded beer yeast (Se-enriched DB-yeast) through fermentation accumulation by re-using discarded Saccharomyces cerevisiae from the beer industry for Se-enriched fodder application. Through a single-factor experiment and L9(34)-orthogonal test for optimization of fermentation conditions, the Se content and biomass of Se-enriched DB-yeast were calculated as 14.95 mg/L and 7.3 g/L, respectively, under the optimized condition. The total amino-acid content of Se-enriched DB-yeast was increased by 9.9% compared with that from DB yeast. Additionally, alkaline amino-acid content was increased, whereas acidic amino-acid and sulfur-containing amino-acid contents were decreased. Reducing capacity, hydroxyl radical removal capacity, and sulfhydryl content after treatment with H2O2 of the Se-enriched DB-yeast extracted protein were obviously increased compared with those of the DB-yeast extracted protein. Mouse and genetically improved farmed tilapia (Oreochromis niloticus) (GIFT) bioassays showed that the Se sedimentation of organs and serum indexes after feeding Se-enriched DB-yeast-containing fodder were higher than those of DB-yeast-containing fodder. The half lethal dose (LD50) of Se-enriched DB-yeast (9260.0 mg/kg body weight (BW), 18.97 mg/kg of Se content, non-toxic level) was considerably higher than that of Na2SeO3 (20.0 mg/kg BW, 5.08 mg/kg of Se content, highly toxic level) against mouse. Therefore, Se-enriched yeast prepared by re-using discarded S. cerevisiae from beer industry fermentation accumulation has the potential to be a safe and effective Se-enriched fodder additive.

Association of serum copper, zinc and selenium levels with risk of metabolic syndrome: A nested case-control study of middle-aged and older Chinese adults

Trace elements, such as copper, zinc and selenium, have been linked to the development of metabolic syndrome. However, previous studies concerning these trace elements in association with metabolic syndrome have presented conflicting results in different countries. The aim of this study was to analyse the association between serum copper, zinc and selenium concentrations and the risk of metabolic syndrome among middle-aged and older Chinese adults. We performed a nested case-control study that included 349 individuals who developed metabolic syndrome (125 males and 224 females) during a 3-year follow-up and 349 controls matched by baseline age (±1 years), sex and area. Serum trace element concentrations were measured using atomic absorption spectrometry. The median serum selenium levels in males and females in the metabolic syndrome group were 82.2 (13.4) μg/L and 82.6 (11.1) μg/L, respectively, which were significantly higher than the serum selenium levels in the control group (p = 0.001 and p < 0.001). After adjusting for potential confounders, the odds ratios of risk for metabolic syndrome in the highest tertile of serum selenium levels were 2.72 [95% confidence interval (CI) 1.43-5.20; p for trend 0.002] for males and 5.30 (95% CI 3.31-8.74; p for trend <0.001) for females, respectively, compared with the lowest tertile. In addition, serum selenium levels were positively correlated with postprandial plasma glucose in both genders (for males: odds ratio 2.42; 95% CI 1.27-4.61; for females: odds ratio 2.11; 95% CI 1.32-3.37) and negatively associated with high-density lipoprotein in only females (odds ratio 3.21; 95% CI 1.75-5.91). These results suggest that higher levels of serum selenium might be an independent risk factor for metabolic syndrome, especially in relation to elevated postprandial plasma glucose and reduced high-density lipoprotein levels. However, we failed to demonstrate an association between copper or zinc status and metabolic syndrome or its components.

Aqueous humor selenium level and open-angle glaucoma

PURPOSE

Selenium supplementation was seen to be linked to glaucoma disease in a previous study (Lillico A. JE, Reid M et al. (2002) Selenium Supplementation and Risk of Glaucoma in the NPC trial University of Arizona, Tucson, AZ., Arizona Cancer Center). As aqueous humor levels of selenium seemed to be associated with primary open-angle glaucoma (POAG), the aim of this study was to analyze concentrations of selenium in aqueous humor samples of patients with POAG and pseudoexfoliation glaucoma (PEXG) in comparison to normal samples.

PATIENTS AND METHODS

Thirty-eight aqueous humor samples from patients undergoing cataract surgery were collected: Eleven patients with PEXG (age 65.8 ± 10.69, female 6, male 5), 12 patients with POAG (age 65.3 ± 10.50, female 7, male 5) and 15 patients without glaucoma (age 70.9 ± 12.83, female 10, male 5, controls). Aqueous humor levels of selenium were measured by Flow-Injection-Inductively-Coupled-Plasma-DRC-Mass-Spectrometry (ICP-DRC-MS).

RESULTS

Maximum likelihood estimation of the least squares means (LS-means) and the relative 95% confidence limits of selenium aqueous humor levels were 6.90 ± 1.03 μg/L (control), 6.74 ± 1.14 μg/L (POAG) and 8.25 ± 1.18 μg/L (PEXG). The data were modeled using a generalized linear model (GLM) analysis, where selenium was set as dependent variable. The model was corrected for group differences in age and gender. The data show no differences among all the calculated differences between the least square means (LS means), taking in consideration the simultaneous 95% confidence limit and the multiple comparison tests with Tukey-Cramer adjustment. The evaluation of the model disclosed that POAG and PEXG patients had no significantly different aqueous humor selenium concentrations compared to controls and to each other. However, the quantile regression analysis of selenium aqueous humor levels showed differences in quantiles for open-angle glaucoma patients considering age and gender.

CONCLUSION

As no significant difference in aqueous humor concentration of selenium was detected between open-angle glaucoma and controls, however, quantile analysis showed differences in quantiles levels for different age ranges in open-angle glaucoma patients, the trace element selenium seemed to be linked to glaucoma disease, yet not in a major role.

Effects of Chinese Cooking Methods on the Content and Speciation of Selenium in Selenium Bio-Fortified Cereals and Soybeans

Cereals and soybeans are the main food sources for the majority of Chinese. This study evaluated the effects of four common cooking methods including steaming, boiling, frying, and milking on selenium (Se) content and speciation in seven selenium bio-fortified cereals and soybeans samples. The Se concentrations in the selected samples ranged from 0.91 to 110.8 mg/kg and selenomethionine (SeMet) was detected to be the main Se species. Total Se loss was less than 8.1% during the processes of cooking except milking, while 49.1% of the total Se was lost in milking soybean for soy milk due to high level of Se in residuals. It was estimated that about 13.5, 24.0, 3.1, and 46.9% of SeMet were lost during the processes of steaming, boiling, frying, and milking, respectively. Meanwhile, selenocystine (SeCys₂) and methylselenocysteine (SeMeCys) were lost completely from the boiled cereals. Hence, steaming and frying were recommended to cook Se-biofortified cereals in order to minimize the loss of Se.

Selenium distribution in the Chinese environment and its relationship with human health: A review

This paper reviewed the Se in the environment (including total Se in soil, water, plants, and food), the daily Se intake and Se content in human hair were also examined to elucidate Se distribution in the environment and its effects on human health in China. Approximately 51% of China is Se deficiency in soil, compared with 72% in the survey conducted in 1989. Low Se concentrations in soil, water, plants, human diet and thus human hair were found in most areas of China. The only significant difference was observed between Se-rich and Se-excessive areas for Se contents in water, staple cereal, vegetables, fruits, and animal-based food, no remarkable contrast was found among other areas (p>0.05). This study also demonstrated that 39-61% of Chinese residents have lower daily Se intakes according to WHO/FAO recommended value (26-34μg/day). Further studies should focus on thoroughly understanding the concentration, speciation, and distribution of Se in the environment and food chain to successfully utilize Se resources, remediate Se deficiency, and assess the Se states and eco-effects on human health.

Relationship between higher serum selenium level and adverse blood lipid profile

BACKGROUND

As the key component of glutathione peroxidase with unique antioxidant properties, selenium has been considered to play an important part on lipid metabolism. However, the associations of serum selenium concentrations with lipid concentrations and dyslipidemia are still controversial.

METHODS

We analyzed cross-sectional data including serum selenium levels, lipid concentrations and other related indexes of 8198 rural Chinese. Serum selenium was measured by inductively coupled plasma mass spectrometry, and total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-c) and low density lipoprotein-cholesterol (LDL-c) of serum were measured with kits.

RESULTS

Overall, mean serum selenium was 120 μg/l. Multivariate liner regression revealed that selenium concentrations were positively correlated with TC (P < 0.001), HDL-c (P < 0.001), TG (P < 0.001) and LDL-c (P < 0.001). Compared with the lowest quintile of serum selenium, participants in quintile 3, 4 and 5 had higher risks of High-TC dyslipidemia (P ≤ 0.02) and High-LDLC dyslipidemia (P < 0.02) after adjusting for covariates. In the stratified analyses, we found that the selenium-dyslipidemia associations were significantly stronger in post-menopausal women (OR: 2.72; 95% CI: 1.97, 4.17) and diabetics (OR: 9.40; 95% CI: 3.02, 29.26).

CONCLUSION

Elevated serum selenium levels were correlated with the increased concentrations of TC, LDL-c, HDL-c and TG, and increased the risk of High-TC and High-LDLC dyslipidemia among rural Chinese. However, the real associations between serum selenium and lipid profile should be verified in specifically designed randomized trials in future.

Relationship between serum selenium, sociodemographic variables, other trace elements and lipid profile in an adult Spanish population

INTRODUCTION

Several studies have shown an inverse relationship between selenium status and cardiovascular health, although epidemiologic evidence yielded by the randomized trials did not find a beneficial effect of selenium administration. The aim of this study was to analyze the association between serum selenium levels and lipid profile adjusted by age, sex and other associated factors among a general adult population in Spain.

MATERIALS AND METHODS

We recruited 372 hospital employee volunteers (60 men and 312 women) with a mean age of 47 (SD: 10.9), whom were given a standardized questionnaire. Serum selenium concentration was measured by electrothermal atomization atomic absorption spectrometry. Serum copper and zinc concentrations were measured using flame atomic absorption spectrometry.

RESULTS

The mean of serum selenium was 79.5μg/L (SD: 11.7) with no sex-dependent differences. In the multivariate linear regression analysis, the associated factors with the mean levels of selenium were: age (β=0.223; CI 95%: 0.101-0.345), p<0.001; widowhood (β=-9.668; CI 95%: -17.234 to -2.102), p=0.012; calcium supplements (β=3.949; CI 95%: 0.059-7.838), p=0.047; zinc (β=0.126; CI 95%: 0.013-0.238), p=0.028 and glucose (β=0.172; CI 95%: 0.062- 0.281), p=0.002; Participants with serum selenium≥79.5μg/L were 1.98 (OR=1.98; CI 95% 1.17-3.35; p=0.011) and 2.04 times (OR=2.04; CI 95% 1.06-3.97; p=0.034) more likely to have cholesterol ≥200mg/dL and LDL-c ≥100mg/dL respectively than those with serum selenium <79.5μg/L.

CONCLUSIONS

Higher selenium was positively associated with increased total and LDL cholesterol but not with HDL-c and triglycerides. More studies are needed in order to confirm the lower serum selenium findings in widows.

Determination of Trace Metal Levels in the General Population of Korea

The purpose of this study was to determine the levels of trace metals in the blood of the general Korean population. A total of 258 healthy individuals, according to their regular medical check-ups, (119 males and 139 females, age ranging from 12 to 78 years old) were enrolled from December 2014 to December 2016. Levels of 10 trace elements were determined using inductively coupled plasma mass spectrometry (ICP-MS). The geometric mean (GM) levels for lead, arsenic, cesium, mercury, aluminum, cadmium, copper, manganese, selenium, and zinc were 15.97 μg/L, 7.19 μg/L, 2.39 μg/L, 3.41 μg/L, 10.57 μg/L, 0.78 μg/L, 979.8 μg/L, 11.06 μg/L, 111.37 μg/L, and 872.7 μg/L, respectively. There were significant gender-related differences in the levels of several metals; male individuals had higher Pb, As, Cs, Hg, and Se than females, while females had higher Cd, Cu, and Mn than males. We noticed remarkably high blood levels of Hg, As and Al in the Korean population. The element concentrations reported represent a new contribution to the knowledge of the blood chemistry for the Korea population. The data can be used to assess the clinical health of this population.

Role of essential trace elements in tuberculosis infection: A review article

Malnutrition is one of the risk factors in tuberculosis (TB) infection. Mineral levels perturbation is seen in patients with TB. Moreover there are some strategies to starve pathogens of essential metals. Here we decided to conclude association between some essential elements and TB. Copper, calcium and iron are essential for hosts' immune system although calcium and iron are necessary for Mycobacterium tuberculosis vitality. Changing these elements alongside with anti-TB therapy is suggested for better treatment outcomes.

Selenium deficiency induced damages and altered expressions of metalloproteinases and their inhibitors (MMP1/3, TIMP1/3) in the kidneys of growing rats

Selenium is an essential trace element for the maintenance of structures and functions of kidney. To evaluate the effects of low selenium on the kidneys of growing rats, newborn rats were fed with selenium deficient and normal diets respectively for 109 days. As a result, rats fed with low selenium diets resulted in a decline in the body weight and the concentration of selenium in the kidney, especially the male rats from the low selenium groups. Moreover, the ultrastructure of glomerulus and tubules were damaged in low selenium group: the glomeruli were observed with hyperplasia of mesangial cells, fusion of podocyte foot processes and thickening of basement membrane; and the tubules were observed with vacuolar degenerated epithelial cells, increased edema fluid or protein solution between cells, microvilli edema, increased cell gaps and decreased cell links. Furthermore, the pathological changes in selenium deficient group included the increase of fibers around renal hilum aorta and in the renal collecting duct, and shed of cells in the proximal convoluted tubules. In addition, up-regulated expressions of matrix metalloproteinases (MMP1/3) and down-regulated expressions of their inhibitors (TIMP1/3) at the mRNA and protein levels were also appeared to be relevant to low selenium. The results suggested that low selenium in diet may cause low selenium concentration in the kidney of growing rat and lead to damages of the ultrastructure and extracellular matrix (ECM) of kidney.

Longitudinal Association between Selenium Levels and Hypertension in a Rural Elderly Chinese Cohort

OBJECTIVES

Results from previous studies have been inconsistent on the association between selenium and hypertension, and very few studies on this subject have focused on the elderly population. The purpose of this study is to examine the relationship between selenium level and hypertension in a rural elderly Chinese cohort.

DESIGN

A longitudinal study was implemented and data were analyzed using logistic regression models and Cox proportional hazards regression model adjusting for potential confounders. The associations between selenium level and prevalent hypertension at baseline and between selenium and incident hypertension were examined.

SETTING

Community-based setting in four rural areas in China.

SUBJECTS

A total of 2000 elderly aged 65 years and over (mean 71.9±5.6 years) participated in this study.

MEASUREMENTS

Nail selenium levels were measured in all subjects at baseline. Blood pressure measures and self-reported hypertension history were collected at baseline, 2.5 years and 7 years later. Hypertension was defined as systolic blood pressure 140 mmHg or higher, diastolic blood pressure 90 mmHg or higher, or reported use of anti-hypertensive medication.

RESULTS

The rate of baseline hypertension was 63.50% in this cohort and the mean nail selenium level is 0.413±0.183μg/g. Multi-covariate adjusted cross-sectional analyses indicated that higher selenium level was associated with higher blood pressure measures at baseline and higher rates of hypertension. For the 635 participants with normal blood pressure at baseline, 360 had developed hypertension during follow-up. The incidence rate for hypertension was 45.83%, 52.27%, 62.50%, 70.48%, and 62.79% from the first selenium quintile to the fifth quintile respectively. Comparing to the lowest quintile group, the hazard ratios were 1.41 (95%CI: 1.03 to1.94), 1.93 (95%CI: 1.40 to 2.67), 2.35 (95%CI: 1.69 to 3.26) and 1.94 (95%CI: 1.36 to 22.77) for the second selenium quintile to the fifth quintile respectively.

CONCLUSIONS

Our findings suggest that high selenium may play a harmful role in the development of hypertension. Future studies are needed to confirm our findings and to elucidate a plausible biological mechanism.

Hair Selenium Levels of School Children in Kashin-Beck Disease Endemic Areas in Tibet, China

Previous studies have shown that the selenium (Se) deficiency is an important factor for the etiology of Kashin-Beck disease (KBD). Although KBD is presently controlled in most regions of China, it is still active in the Tibetan Plateau. The present study aimed to assess the nutritional status of selenium in school children by using the Se level in hair as a biomarker in KBD endemic areas of Lhasa in Tibet, China. Hair samples of 155 school children aged 6-15 years were collected in both KBD areas and non-KBD areas of Lhasa in 2013. The Se level in the hair samples was determined by inductive coupled plasma mass spectrometry (ICP-MS). The average concentration of Se in children's hair was 0.232 μg/g in KBD areas of Lhasa, which was significantly higher than the data reported decades ago. A significant difference in hair Se was observed between the boys (0.255 μg/g) and the girls (0.222 μg/g) in the studied KBD areas (P < 0.01, Mann-Whitney U test), but hair Se did not vary by age or region. School children in KBD endemic areas in Lhasa likely have improved Se status as a result of high Se content staple food substitution with the enforcement of Free Education Policy and Nutrition Improvement Plan in Tibet. Nevertheless, there were still 20.3 % of students with low Se status (hair Se <0.20 μg/g), which showed that Se status of school children was also partly affected by low Se environment in KBD endemic areas of Lhasa.

Understanding the paradox of selenium contamination in mercury mining areas: high soil content and low accumulation in rice

Rice is an important source of Se for billions of people throughout the world. The Wanshan area can be categorized as a seleniferous region due to its high soil Se content, but the Se content in the rice in Wanshan is much lower than that from typical seleniferous regions with an equivalent soil Se level. To investigate why the Se bioaccumulation in Wanshan is low, we measured the soil Se speciation using a sequential partial dissolution technique. The results demonstrated that the bioavailable species only accounted for a small proportion of the total Se in the soils from Wanshan, a much lower quantity than that found in the seleniferous regions. The potential mechanisms may be associated with the existence of Hg contamination, which is likely related to the formation of an inert Hg-Se insoluble precipitate in soils in Wanshan.

The changing selenium nutritional status of Chinese residents

The selenium (Se) content in human hair is useful as an indicator of human Se intake and status. In this regard, when measuring the hair Se concentrations in Chinese inhabitants across northeast to southeast China, the results indicated that generally 84% of all residents have normal hair Se content. Between the sexes, the average hair Se content of males was higher than that of females, irrespective of districts. When comparing geographical regions, the average hair Se content of southern residents was greater than that of northern residents, regardless of gender. Historically, the overall hair Se content of today’s inhabitants decreased between 24% and 46% when compared with the inhabitants living in the same geographic region 20 years ago. The decrease of hair Se content may be related to the overall decrease of grain consumption and the lower Se content in the staple food rice.

Selenium levels and hypertension: a systematic review of the literature

OBJECTIVE

Se is an antioxidant micronutrient and has been studied for its potential role in CVD prevention. The purpose of the present study was to conduct a systematic review of the literature on the relationship between Se and hypertension.

DESIGN

We conducted a systematic literature search in PubMed and OVID of studies on Se levels and hypertension or blood pressure published in English up to June 2011. Articles meeting inclusion criteria were reviewed and the following information was gathered from each publication: study setting, participant demographics, exclusion criteria, intervention if applicable, medium of Se measure, mean level of Se, outcome definition, relationship between Se and the outcome variable, significance of this relationship, and covariates. In studies that also reported glutathione peroxidase levels, we extracted results on the relationship between glutathione peroxidase and hypertension.

RESULTS

Twenty-five articles were included. Approximately half of the studies reported no significant relationship between Se and hypertension. Of the remaining studies, about half found that higher Se levels were associated with lower blood pressure and the other half found the opposite relationship. The studies varied greatly in terms of study population, study design and Se levels measured in participants.

CONCLUSIONS

Based on the present systematic review, there is no conclusive evidence supporting an association between Se and hypertension. Randomized controlled trials and prospective studies with sufficient sample size in populations with different Se levels are needed to fully investigate the relationship between Se and hypertension.

Blood selenium concentration in a selected population of children inhabiting industrial regions in Upper Silesia (Poland)

PURPOSE

Present study aimed at determining blood selenium concentration (Se-B) in a selected population of children inhabiting industrial regions.

METHODS

The studies were conducted on a group of 267 children inhabiting industrial regions in Upper Silesia (Poland). Determination of Se-B was performed using hydride generation atomic absorption technique.

RESULTS

In the studied group of children mean Se-B amounted to 76.75±12.52μg/L. Only in 38.20% of studied children the estimated Se-B could be regarded as an optimal. Children with underweight (BMI<15th centile) manifested a significantly lower Se-B than children with BMI within the normal range (BMI 15-85th centile). In the entire study group of children a significant positive linear correlation was disclosed between BMI and Se-B (r=0.16, p<0.05). Regression analysis demonstrated that in the studied subgroup of children (with normal height, body mass and BMI) a higher BMI represented an independent factor of Se-B increase and a more pronounced age an independent factor of Se-B decrease. Moreover, maternal education represented an independent factor of Se-B increase in the studied group of children (with normal height, body mass and BMI).

CONCLUSIONS

Se-B in the studied group children from industrial area in Upper Silesia corresponded with the lower range of blood selenium concentrations noted in recent years in other populations. A negative relationship was documented between age and Se-B and a positive relationship between BMI of a child and maternal education on one hand and Se-B of a child on the other.

Group I mGluR antagonist rescues the deficit of D1-induced LTP in a mouse model of fragile X syndrome

BACKGROUND

Fragile X syndrome (FXS) is caused by the absence of the mRNA-binding protein Fragile X mental retardation protein (FMRP), encoded by the Fmr1 gene. Overactive signaling by group 1 metabotropic glutamate receptor (Grp1 mGluR) could contribute to slowed synaptic development and other symptoms of FXS. Our previous study has identified that facilitation of synaptic long-term potentiation (LTP) by D1 receptor is impaired in Fmr1 knockout (KO) mice. However, the contribution of Grp1 mGluR to the facilitation of synaptic plasticity by D1 receptor stimulation in the prefrontal cortex has been less extensively studied.

RESULTS

Here we demonstrated that DL-AP3, a Grp1 mGluR antagonist, rescued LTP facilitation by D1 receptor agonist SKF81297 in Fmr1KO mice. Grp1 mGluR inhibition restored the GluR1-subtype AMPA receptors surface insertion by D1 activation in the cultured Fmr1KO neurons. Simultaneous treatment of Grp1 mGluR antagonist with D1 agonist recovered the D1 receptor signaling by reversing the subcellular redistribution of G protein-coupled receptor kinase 2 (GRK2) in the Fmr1KO neurons. Treatment of SKF81297 alone failed to increase the phosphorylation of NR2B-containing N-methyl D-aspartate receptors (NMDARs) at Tyr-1472 (p-NR2B-Tyr1472) in the cultures from KO mice. However, simultaneous treatment of DL-AP3 could rescue the level of p-NR2B-Tyr1472 by SKF81297 in the cultures from KO mice. Furthermore, behavioral tests indicated that simultaneous treatment of Grp1 mGluR antagonist with D1 agonist inhibited hyperactivity and improved the learning ability in the Fmr1KO mice.

CONCLUSION

The findings demonstrate that mGluR1 inhibition is a useful strategy to recover D1 receptor signaling in the Fmr1KO mice, and combination of Grp1 mGluR antagonist and D1 agonist is a potential drug therapy for the FXS.

Speciation of selenium in groundwater: seasonal variations and redox transformations

Speciation of selenium in groundwater is essential from the viewpoint of toxicity to organisms and biogeochemical cycling. Selenium speciation in groundwater is controlled by aquifer redox conditions, microbial transformations, dissolved oxygen (DO) and other redox couples. A suburban area of Chennai city in India, where improper waste disposal measures have been practiced is selected for this study. Se(IV), Se(VI) and other hydrochemical parameters were monitored in shallow ground water during pre- and post-monsoon seasons for a period of three years. The objective of the study was to investigate the effect of groundwater recharge on selenium speciation. The concentration of Se(IV), and Se(VI) ranged between 0.15-0.43 μg L(-1) and 0.16-4.73 μg L(-1), respectively. During post-monsoon period the concentration of Se(IV), and Se(VI) ranged between 0.15-1.25 μg L(-1) and 0.58-10.37 μg L(-1), respectively. Se(VI) was the dominant species of selenium during the pre- and post-monsoon periods. During the post-monsoon periods, leaching of selenium from soil was more effective due to the increased oxidizing nature of the groundwater as indicated by the DO and redox potential (Eh) measurements. This finding has important implications on the behavior of selenium in groundwater, and also on the health of people consuming groundwater from seleniferous areas.

Assessment of reference ranges for blood Cu, Mn, Se and Zn in a selected Italian population

The reference ranges for blood Cu, Mn, Se and Zn of 215 adult subjects non-occupationally exposed and living in the Nuoro province (Sardinia, insular Italy) were assessed. Metals were determined by sector field inductively coupled plasma mass spectrometry after microwave-assisted acid digestion of blood. The blood reference ranges estimated as P5-P95 percentiles (geometric mean, GM) were 776-1495μg/L (1036μg/L) for Cu; 4.73-17.0μg/L (8.91μg/L) for Mn; 106-185μg/L (140μg/L) for Se and 4686-8585μg/L (6418μg/L) for Zn. These results were then stratified for sex, age, alcohol consumption, smoking habit and living area. The GM value of Cu was significantly higher in females (1127μg/L) than in males (957μg/L). Age, alcohol intake, smoking habit and residential area did not influence blood Cu. The GM of Mn was significantly higher in females (9.98μg/L) respect to males (8.01μg/L) and in drinkers (9.67μg/L) compared to non-drinkers (8.38μg/L). The other variables did not change the Mn data. Selenium concentrations did not differ significantly as a function of individuals factors. With reference to Zn, males had GM of 6804μg/L and females of 6031μg/L, and more blood Zn was found in subjects consuming alcohol (6618μg/L) respect to abstainers (6155μg/L). In addition, blood Zn was not affected by age, smoking habit and place of living.

Environmental and human health risk assessment for essential trace elements: considering the role for geoscience

In environmental and human health protection, the role for geoscience may be expressed by how it enhances certainty in the hazard potential models that support risk assessment. For geochemical hazards, certainty reflects how well geoscience simplifies variability in the element concentrations and in the environmental conditions associated with exposure pathways. Through mineralogy, geoscience establishes natural geochemical background variability in terms of provenance, process, and past, and it links hazard potential to the physical and chemical transformation due to weathering and soil formation. The interpretation of hazard potential may be expressed by how analytical protocol, expressed by grain size and strength of acid decomposition, combines with geological factors, expressed by (1) mineralogy and mineral partitioning and (2) environmental cofactors, including moisture, pH, buffering capacity, and porosity. With this type of knowledge, geoscience enhances the potential to identify covariant relations between hazard indicators and disease, and to resolve potential causal factors.

Serum selenium level in healthy Koreans

Of trace elements in the serum of living organisms, selenium (Se) is an essential mineral and plays the role of an antioxidant as selenoproteins protecting the organism against oxidative damage induced by hydrogen peroxide, other lipid hydroperoxides, and their derivatives. The aim of this study was to determine the mean serum Se levels in healthy Korean volunteers (50 males and 50 females) by using an inductively coupled plasma-mass spectrometry method. The samples were collected at the Health Promotion Centre of Kangnam St. Mary's Hospital, College of Medicine, the Catholic University of Korea, Kangnam District, Seoul in accordance with procedures approved by the Institutional Review Board of the Catholic University of Korea. The mean serum Se level in healthy subjects was 112.05 +/- 30.42 microg/l. For gender, it was 120.81 +/- 27.37 microg/l for females and 103.29 +/- 31.05 microg/l for males. From the study result, there was a significant difference between the mean Se concentrations of gender groups (p = 0.0035). Also, the study indicated no effect of age on Se levels (p > 0.05) in the healthy individuals.