Comparison of the serum selenium content of healthy adults living in the Antwerp region (Belgium) with recent literature data

Selenoprotein P increases upon selenium and coenzyme Q10 supplementation and is associated with telomere length, quality of life and reduced inflammation and mortality

BACKGROUND

Selenoprotein P (SELENOP) transports selenium to extrahepatic tissues and is a biomarker of selenium status. Low soil selenium leads to low dietary selenium intake. A consequence is an increased risk of cardiovascular disease.

OBJECTIVE

To investigate clinical aspects associated with SELENOP deficiency, including biomarkers of inflammation, quality of life, and mortality within 12 years, and the effect of dietary selenium and coenzyme Q10 supplementation on SELENOP.

METHODS

SELENOP was determined at inclusion and after four years of supplementation in 403 elderly community-living participants low in selenium receiving selenium yeast (200 μg/day) and coenzyme Q10 (200 mg/day), or placebo. Pre-intervention, the average serum selenium level was 67 μg/L. T-tests, repeated measures of variance, Cox proportional regressions analyses, Kaplan-Meier graphs and ANCOVA analyses were applied. Associations with biomarkers of inflammation, telomere length, quality of life and mortality were investigated. Benchmark modelling was used to determine the serum selenium concentration at which the saturation levels of SELENOP and GPx3 was achieved. Comparison with GPx3 and serum selenium to identify increased mortality risk was performed, and the effect of supplementation on SELENOP levels were evaluated.

RESULTS

Inverse associations were observed between the level of SELENOP at inclusion and biomarkers for inflammation. At follow-up, shorter telomere lengths were seen in those with low levels of SELENOP at inclusion, whereas high levels of SELENOP were associated with better quality of life and decreased mortality. SELENOP had increased prognostic power compared to GPx3 and selenium. Saturation of SELENOP was achieved at a serum selenium level of 146 μg/L, and for GPx3 at 99 μg/L. Supplementation induced higher levels of SELENOP.

CONCLUSION

Significant associations between SELENOP and inflammation, length of telomeres, quality of life, and mortality were observed. Thus, selenium supplementation improved SELENOP expression, thereby facilitating systemic selenium bioavailability and resulting in the observed positive health effects.

Supplementation with selenium and coenzyme Q10 in an elderly Swedish population low in selenium - positive effects on thyroid hormones, cardiovascular mortality, and quality of life

BACKGROUND

Selenium-dependent deiodinases play a central role in thyroid hormone regulation and metabolism. In many European countries, insufficient selenium intake may consequently lead to adverse effects on thyroid function. In this randomised placebo-controlled double-blind study, we examined the effect of supplementation with selenium and coenzyme Q10 on thyroid hormonal status, cardiovascular (CV) mortality and health-related quality of life (Hr-QoL).

METHODS

Free T3, free T4, reverse T3, and TSH were determined in 414 individuals at baseline, and the effect of selenium yeast (200 µg/day) and coenzyme Q10 (200 mg/day) supplementation on hormone concentrations, CV mortality and Hr-QoL was evaluated after 48 months using Short Form 36 (SF-36). Pre-intervention plasma selenium was low, mean 67 µg/L, corresponding to an estimated intake of 35 µg/day. Changes in concentrations of thyroid hormones following the intervention were assessed using T-tests, repeated measures of variance, and ANCOVA analyses.

RESULTS

In the total population, the group with the lowest selenium concentration at baseline presented with significantly higher levels of TSH and lower levels of fT3 as compared to subjects with the highest selenium concentration. Supplementation with selenium and coenzyme Q10 for 4 years significantly increased fT3 and rT3, decreased fT4, and diminished the increase in TSH levels compared with placebo treatment (p = 0.03, all). In the placebo group, TSH and fT4 values above the median were associated with an increase in 10-year CV mortality, as compared with the mortality rate among those with TSH and fT4 below the median (p < 0.04, both), with no difference in mortality rate according to TSH and fT4 levels in the active intervention group. Similarly, TSH > median and fT3 < median were associated with a decline in mental Hr-QoL measures vs. TSH < and fT3 > median in the placebo group during 4 years of follow-up, but this was wiped out in the active group.

CONCLUSIONS

Supplementation with selenium and coenzyme Q10 had a beneficial effect on thyroid hormones with respect to CV mortality and Hr-QoL outcomes. The initial deficient selenium status was associated with an impaired thyroid function and the changes in thyroid hormone levels can be explained by increased activity of deiodinases. We conclude that a substantial part of the elderly study population might suffer from suboptimal thyroidal function with adverse clinical implications due to selenium deficiency.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov and has the identifier NCT01443780. Since it was not mandatory to register at the time the study began, the study has been registered retrospectively.

Selenium Concentration Is Positively Associated with Triglyceride-Glucose Index and Triglyceride Glucose-Body Mass Index in Adults: Data from NHANES 2011-2018

Compiling evidence supports that selenium plays a vital role in glucose metabolism. Triglyceride-glucose index (TyG) and triglyceride-glucose-body mass index (TyG-BMI) are commonly used in epidemiologic studies to evaluate insulin resistance and cardiovascular disease (CVD) risks. This study is aimed to investigate the association between whole blood selenium concentration and TyG and TyG-BMI. A total of 6290 participants (age ≥ 20 years) from the National Health and Nutrition Examination Survey (NHANES) 2011-2018 were included. Multiple linear regression models were used to examine the association between blood selenium quartiles and TyG and TyG-BMI. Subgroup analysis stratified by diabetes status was also performed. The adjusted model showed a positive association between TyG and blood selenium concentration (β [95%CI] = 0.099 [0.063, 0.134], p < 0.001) and TyG-BMI (β [95%CI] = 3.185 [2.102, 4.268], p < 0.001). The association persisted after stratification by diabetes status (p < 0.001). Participants were stratified into four quartiles based on selenium concentration (Q1: 1.08-2.24 μmol/L, Q2: 2.25-2.42 μmol/L, Q3: 2.43-2.62 µmol/L, Q4: 2.63-8.08). Compared with the Q1 group, TyG in the Q3 and Q4 groups was significantly higher (β = 0.075 [95%CI 0.039 to 0.112] and β = 0.140 [95%CI 0.103 to 0.176], respectively). Additionally, TyG-BMI in the Q2, Q3, and Q4 groups was higher than that in the Q1 group (β = 1.189 [95%CI 0.065 to 2.314], β = 2.325 [95%CI 1.204 to 3.446], and β = 4.322 [95%CI 3.210 to 5.435], respectively). Blood level of selenium was positively associated with TyG and TyG-BMI, indicating that excessive blood selenium may be associated with impaired insulin sensitivity and increased risk of cardiovascular disease.

Effects of an Intervention with Selenium and Coenzyme Q10 on Five Selected Age-Related Biomarkers in Elderly Swedes Low in Selenium: Results That Point to an Anti-Ageing Effect-A Sub-Analysis of a Previous Prospective Double-Blind Placebo-Controlled Randomised Clinical Trial

Background: Ageing is associated with cardiovascular disease (CVD). As no single biomarker reflects the full ageing process, we aimed to investigate five CVD- and age-related markers and the effects of selenium and coenzyme Q10 intervention to elucidate the mechanisms that may influence the course of ageing. Methods: This is a sub-study of a previous prospective double-blind placebo-controlled randomized clinical trial that included 441 subjects low in selenium (mean age 77, 49% women). The active treatment group (n = 220) received 200 µg/day of selenium and 200 mg/day of coenzyme Q10, combined. Blood samples were collected at inclusion and after 48 months for measurements of the intercellular adhesion molecule (ICAM-1), adiponectin, leptin, stem cell factor (SCF) and osteoprotegerin (OPG), using ELISAs. Repeated measures of variance and ANCOVA evaluations were used to compare the two groups. In order to better understand and reduce the complexity of the relationship between the biomarkers and age, factor analyses and structural equation modelling (SEM) were performed, and a structural model is presented. Results: Correlation analyses of biomarker values at inclusion in relation to age, and relevant markers related to inflammation, endothelial dysfunction and fibrosis, demonstrated the biomarkers' association with these pathological processes; however, only ICAM1 and adiponectin were directly correlated with age. SEM analyses showed, however, that the biomarkers ICAM-1, adiponectin, SCF and OPG, but not leptin, all had significant associations with age and formed two independent structural factors, both significantly related to age. While no difference was observed at inclusion, the biomarkers were differently changed in the active treatment and placebo groups (decreasing and increasing levels, respectively) at 48 months (p ≤ 0.02 in all, adjusted), and in the SEM model, they showed an anti-ageing impact. Conclusions: Supplementation with selenium/Q10 influenced the analysed biomarkers in ways indicating an anti-ageing effect, and by applying SEM methodology, the interrelationships between two independent structural factors and age were validated.

Plasma and vitreous selenium concentrations in patients with type 2 diabetes and diabetic retinopathy

BACKGROUND

This work aimed to determine and compare plasma and vitreous selenium (Se) concentrations in patients with type 2 diabetes and diabetic retinopathy (DR).

METHODS

A total of 60 type-2-diabetes patients including 20 without DR, 20 with non-proliferative DR (NPDR), and 20 with proliferative diabetic retinopathy (PDR), were involved in this study. Blood plasma samples were collected from above 60 patients and 20 normal controls (without diabetes). Twenty control vitreous samples were obtained from the eyes presenting a macular hole and epimacular membrane. Vitreous samples were also collected from PDR patients receiving one-week intravitreal anti-VEGF therapy or not. Plasma and vitreous Se concentrations were determined by inductively coupled plasma mass spectrometry.

RESULTS

Plasma Se concentrations in PDR patients (163.74 ± 32.68 μg/L) were significantly higher than those in normal control patients (121.59 ± 28.33 μg/L), NPDR patients (130.34 ± 29.11 μg/L), and the patients without DR (81.23 ± 20.59 μg/L) (all P < .001). Similarly, Se concentrations in vitreous samples of PDR patients (56.30 ± 12.03 μg/L) were consistently higher than those in control vitreous samples (26.26 ± 6.53 μg/L). In addition, vitreous Se concentrations in PDR patients decreased to 47.76 ± 9.72 μg/L after intravitreal injection of the anti-VEGF drug ranibizumab for one week, which was significantly lower than those before injection (P = .02). Plasma VEGF levels of diabetic patients were lower than those of the normal controls (P < .001). On the contrary, the vitreous VEGF level in the PDR group (913.61 ± 193.32 pg/mL) was significantly higher than that of the normal control group (101.23 ± 21.33 pg/mL) (P < .001).

CONCLUSION

The elevation of Se concentrations may be an important risk factor in plasma and vitreous with diabetic retinopathy among type-2-diabetes patients. The elevated VEGF may be also closely related to the intraocular Se concentration in PDR patients.

Serum selenium concentration in patients with autoimmune thyroid disease

Abstract.

Improved cardiovascular health by supplementation with selenium and coenzyme Q10: applying structural equation modelling (SEM) to clinical outcomes and biomarkers to explore underlying mechanisms in a prospective randomized double-blind placebo-controlled intervention project in Sweden

Purpose

Selenium and coenzyme Q10 have synergistic antioxidant functions. In a four-year supplemental trial in elderly Swedes with a low selenium status, we found improved cardiac function, less cardiac wall tension and reduced cardiovascular mortality up to 12 years of follow-up. Here we briefly review the main results, including those from studies on biomarkers related to cardiovascular risk that were subsequently conducted. In an effort, to explain underlying mechanisms, we conducted a structured analysis of the inter-relationship between biomarkers.

Methods

Selenium yeast (200 µg/day) and coenzyme Q10 (200 mg/ day), or placebo was given to 443 elderly community-living persons, for 48 months. Structural Equation Modelling (SEM) was used to investigate the statistical inter-relationships between biomarkers related to inflammation, oxidative stress, insulin-like growth factor 1, expression of microRNA, fibrosis, and endothelial dysfunction and their impact on the clinical effects. The main study was registered at Clinicaltrials.gov at 30th of September 2011, and has the identifier NCT01443780.

Results

In addition to positive clinical effects, the intervention with selenium and coenzyme Q10 was also associated with favourable effects on biomarkers of cardiovascular risk. Using these results in the SEM model, we showed that the weights of the first-order factors inflammation and oxidative stress were high, together forming a second-order factor inflammation/oxidative stress influencing the factors, fibrosis (β = 0.74; p < 0.001) and myocardium (β = 0.65; p < 0.001). According to the model, the intervention impacted fibrosis and myocardium through these factors, resulting in improved cardiac function and reduced CV mortality.

Conclusion

Selenium reduced inflammation and oxidative stress. According to the SEM analysis, these effects reduced fibrosis and improved myocardial function pointing to the importance of supplementation in those low on selenium and coenzyme Q10.

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.

Pharmaconutrition revisited for critically ill patients with coronavirus disease 2019 (COVID-19): Does selenium have a place?

Coronavirus disease 2019 (COVID-19) is a global pandemic causing one of the biggest challenges for critical care medicine. Mortality from COVID-19 is much greater in elderly men, many of whom succumb to acute respiratory distress syndrome (ARDS) triggered by the viral infection. Because there is no specific antiviral treatment against COVID-19, new strategies are urgently needed. Selenium is an essential trace element with antioxidant and immunomodulatory effects. Poor nutritional status increases the pathogenicity of viruses and low selenium in particular can be a determinant of viral virulence. In the past decade, selenium pharmaconutrition studies have demonstrated some reduction in overall mortality, including how reduced incidence of ventilator-associated pneumonia and infectious complications such as ARDS in the critically ill. Consequently, we postulate that intravenous selenium therapy, could be part of the therapeutic fight against COVID-19 in intensive care unit patients with ARDS and that outcomes could be affected by age, sex, and body weight. Our working hypothesis addresses the question: Could high-dose selenite pharmaconutrition, as an early pharmacologic intervention, be effective at reducing the incidence and the progression from type 1 respiratory failure (non-ARDS) to severe ARDS, multiorgan failure, and new infectious complications in patients with COVID-19 patients?

Supplemental selenium and coenzyme Q10 reduce glycation along with cardiovascular mortality in an elderly population with low selenium status - A four-year, prospective, randomised, double-blind placebo-controlled trial

BACKGROUND

A low intake of selenium has been shown to increase the risk of cardiovascular mortality, and supplementation of selenium and coenzyme Q10 influences this. The mechanism behind is unclear although effects on inflammation, oxidative stress and microRNA expression have been reported. Fructosamine, a marker of long-term glycaemic control, is also a marker of increased risk of heart disease and death, even in non-diabetics.

OBJECTIVE

To analyse the impact of selenium and coenzyme Q10 supplementation on the concentration of fructosamine. Also, the relation between pre-intervention serum selenium concentration and the effect on fructosamine of the intervention was studied.

METHODS

Fructosamine plasma concentration was determined in 219 participants after six and 42 months of intervention with selenium yeast (200 μg/day) and coenzyme Q10 (200 mg/ day) (n = 118 of which 20 had diabetes at inclusion), or placebo (n = 101 of which 18 had diabetes at inclusion). Pre-intervention, the serum selenium levels were 67 μg/L (active treatment group: 66.6 μg/L; placebo group: 67.4 μg/L), corresponding to an estimated intake of 35 μg/day. Changes in concentrations of fructosamine following intervention were assessed by the use of T-tests, repeated measures of variance, and ANCOVA analyses.

RESULTS

Post-intervention selenium concentrations were 210 μg/L in the active group and 72 μg/L in the placebo group. A lower concentration of fructosamine could be seen as a result of the intervention in the total population (P = 0.001) in both the males (P = 0.04) and in the females (P = 0.01) in the non-diabetic population (P = 0.002), and in both the younger (<76 years) (P = 0.01) and the older (≥76 years) participants (P = 0.03). No difference could be demonstrated in fructosamine concentration in the diabetic patients, but the total sample was small (n = 38). In subjects with a low pre-intervention level of serum selenium the intervention gave a more pronounced decrease in fructosamine compared with those with a higher baseline selenium level.

CONCLUSION

A significantly lower concentration of fructosamine was observed in the elderly community-living participants supplemented with selenium and coenzyme Q10 for 42 months compared to those on the placebo. As oxidative mechanisms are involved in the glycation of proteins, less glycoxidation could be a result of the supplementation of selenium and coenzyme Q10, which could have contributed to lower cardiac mortality and less inflammation, as has earlier been reported. This study was registered at Clinicaltrials.gov, and has the identifier NCT01443780.

Significant decrease of von Willebrand factor and plasminogen activator inhibitor-1 by providing supplementation with selenium and coenzyme Q10 to an elderly population with a low selenium status

Purpose

Endothelial dysfunction and inflammation are conditions which fuel atherosclerosis and ischaemic heart disease. We have previously reported reduced cardiovascular (CV) mortality following supplementation with selenium and coenzyme Q10 to 443 elderly individuals with low selenium status (mean 67 μg/L) for 4 years. Here, we wanted to evaluate a possible association between the supplementation and the plasma concentrations of the von Willebrand factor (vWf), and the plasminogen activator inhibitor-1 (PAI-1), as they, besides other functions, are also strongly associated with endothelial function.

Methods

In this sub-study, 308 individuals (active substance: 157, placebo: 151) were included. Blood samples were drawn after 6 and 36 months and vWf and PAI-1 were determined in plasma by ELISA. Changes in concentrations of the biomarkers were evaluated by the use of T tests, repeated measures of variance, and ANCOVA analyses.

Results

The active treatment group presented a lower level of vWf after 36 months compared with the placebo group (1.08 U/mL vs. 5.10 U/mL; p = 0.0007). The results were validated through the repeated measures of variance evaluation. The PAI-1 levels showed an equally significant decrease in the active group (26.2 ng/mL vs. 49.2 ng/mL; p = 0.0002) and were also validated through repeated measures of variance evaluation.

Conclusion

In this sub-study on elderly receiving selenium and coenzyme Q10, or placebo we found significantly lower levels of vWf and PAI-1 in the active treatment group as compared to the placebo group. We interpret this as a better endothelial function because of the intervention, which accords with a previous finding of reduced CV mortality.

Is selenium intake associated with the presence of depressive symptoms among US adults? Findings from National Health and Nutrition Examination Survey (NHANES) 2011-2014

OBJECTIVES

This study aimed to examine the cross-sectional association between dietary and serum selenium measures and depressive symptoms among a nationally representative sample of US adults.

METHODS

Dietary selenium intake and serum selenium concentration were evaluated on 7725 adult participants from National Health and Nutrition Examination Survey (NHANES) 2011-2014. Participants' selenium intake, assessed by 24-h recall, was classified based on the recommended dietary allowance (dietary selenium intake ≥ 55 μg/d) and estimated average requirement (dietary selenium intake ≥ 45 μg/d) criteria. Serum selenium and depressive symptoms were assessed using inductively coupled plasma mass spectrometry and a patient health questionnaire or use of an antidepressant, respectively. Univariate and multivariate logistic regression, accounting for the complex survey design of NHANES, were employed to estimate the cross-sectional association between measures of selenium and the presence of depressive symptoms.

RESULTS

The median selenium concentration was 193.9 µg/L (interquartile range = 179.3-209.3). Approximately 8% of the participants met the case definition for depressive symptoms. Based on the recommended dietary allowance of selenium, participants not meeting the recommended dietary intake, compared with those meeting the requirement, had higher odds of depressive symptoms (odds ratio [OR] = 1.57, 95% confidence interval [CI]: 1.03-2.38). When analyzing by quintile of dietary selenium intakes, compared with the first quintile, participants in higher quintiles had significantly lower odds of depressive symptoms. However, based on quintiles of serum selenium and using the first quintile as referent category, except for quintile 3, results indicated a higher but not significant association (quintile 2 [OR = 1.08, 95% CI: 0.73-1.61], quintile 4 [OR = 1.17, 95% CI: 0.89-1.55], and quintile 5 [OR = 1.14, 95% CI: 0.83-1.58]). Power analysis indicated sufficient power. Notably, study participants had a very high serum selenium concentration. The findings, although not significant, between serum selenium concentrations and depressive symptoms had a U-shaped association, supported by the current literature.

CONCLUSIONS

Our study supports an inverse association between participants recommended dietary intake of selenium and depressive symptoms. Although results were not statistically significant for the association by quartile of serum selenium concentrations and depressive symptoms, a U-shaped association was identified.

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.

The Protective Role of Selenium in AFB1-Induced Tissue Damage and Cell Cycle Arrest in Chicken's Bursa of Fabricius

Aflatoxin B₁ (AFB₁) is a naturally occurring secondary metabolites of Aspergillus flavus and Aspergillus parasiticus, and is the most toxic form of aflatoxins. Selenium (Se) with antioxidant and detoxification functions is one of the essential trace elements for human beings and animals. This study aims to evaluate the protective effects of Se on AFB₁-induced tissue damage and cell cycle arrest in bursa of Fabricius (BF) of chickens. The results showed that a dietary supplement of 0.4 mg·kg^-1 Se alleviated the histological lesions induced by AFB₁, as demonstrated by decreasing vacuoles and nuclear debris, and relieving oxidative stress. Furthermore, flow cytometry studies showed that a Se supplement protected AFB₁-induced G₂M phase arrest at 7 days and G₀G₁ phase arrest at 14 and 21 days. Moreover, the mRNA expression results of ATM, Chk2, p53, p21, cdc25, PCNA, cyclin D₁, cyclin E₁, cyclin B₃, CDK6, CDK2, and cdc2 indicated that Se supplement could restore these parameters to be close to those in the control group. It is concluded that a dietary supplement of 0.4 mg kg^-1 Se could diminish AFB₁-induced immune toxicity in chicken's BF by alleviating oxidative damage and cell cycle arrest through an ATM-Chk2-cdc25 route and the ATM-Chk2-p21 pathway.

Life satisfaction among elderly patients in Nepal: associations with nutritional and mental well-being

BACKGROUND

Nepal's demography is aging rapidly, yet few studies to date have examined how this has affected the health and well-being of the elderly, defined as those above 60 years in Nepal's Senior Citizen Act (2006). Our study, abbreviated NepEldQOLII, aims to assess perceived life satisfaction, and evaluate its relationship with nutritional health and mental well-being among the burgeoning Nepalese elderly population.

METHODS

A cross-sectional survey among 289 Nepalese elderly, aged ≥60 years, attending an outpatient clinic of a hospital in Kathmandu, Nepal was conducted. Nutritional status, depression, and life satisfaction were assessed by a mini-nutritional assessment scale (range: 0-14), a geriatric depression scale (range: 0-15), and a satisfaction with life scale (range: 5-35), respectively. Mediation analyses, adjusted for age, sex, marital status, and family type, were used to assess mediating relationships between nutritional and mental wellbeing with life satisfaction as the outcome.

RESULTS

Approximately 21% of the participants were dissatisfied with their life. Life satisfaction was positively associated with being married, high family income, involvement in active earning, and a high nutritional score. Conversely, life satisfaction was inversely associated with living in a nuclear (as opposed to joint) family, the perception of having worse health than peers, the perception of being ignored/hated due to old age, and a higher depression score. In mediation analyses, both nutrition (β = 0.48, bias-corrected and accelerated (BCa) 95% CI: 0.27, 0.69) and depression (β = - 0.87, BCa 95% CI: -1.01, - 0.74) had significant direct associations with life satisfaction. Furthermore, both nutrition (β = 0.30, BCa 95% CI: 0.13, 0.49) and depression (β = - 0.07, BCa 95% CI: -0.14, - 0.03) mediate each other's association with life satisfaction. Nutritional score mediated 7% of the total association between depression and life satisfaction; depression mediated 38% of the total association between nutrition and life satisfaction.

CONCLUSIONS

Life satisfaction shows a pattern of decline as nutritional and mental health status decrease. Both depression and under-nutrition had a significant association with life satisfaction. The pathway by which nutrition affects life satisfaction is influenced by depression as a mediator. Moreover, nutritional status explained a small portion of the relationship between depression and life satisfaction. These observed preliminary findings should be confirmed in future longitudinal studies.

Still reduced cardiovascular mortality 12 years after supplementation with selenium and coenzyme Q10 for four years: A validation of previous 10-year follow-up results of a prospective randomized double-blind placebo-controlled trial in elderly

BACKGROUND

Selenium and coenzyme Q10 are both necessary for optimal cell function in the body. The intake of selenium is low in Europe, and the endogenous production of coenzyme Q10 decreases as age increases. Therefore, an intervention trial using selenium and coenzyme Q10 for four years as a dietary supplement was performed. The main publication reported reduced cardiovascular mortality as a result of the intervention. In the present sub-study the objective was to determine whether reduced cardiovascular (CV) mortality persisted after 12 years, in the supplemented population or in subgroups with diabetes, hypertension, ischemic heart disease or reduced functional capacity due to impaired cardiac function.

METHODS

From a rural municipality in Sweden, four hundred forty-three healthy elderly individuals were included. All cardiovascular mortality was registered, and no participant was lost to the follow-up. Based on death certificates and autopsy results, mortality was registered.

FINDINGS

After 12 years a significantly reduced CV mortality could be seen in those supplemented with selenium and coenzyme Q10, with a CV mortality of 28.1% in the active treatment group, and 38.7% in the placebo group. A multivariate Cox regression analysis demonstrated a reduced CV mortality risk in the active treatment group (HR: 0.59; 95%CI 0.42-0.81; P = 0.001). In those with ischemic heart disease, diabetes, hypertension and impaired functional capacity we demonstrated a significantly reduced CV mortality risk.

CONCLUSIONS

This is a 12-year follow-up of a group of healthy elderly participants that were supplemented with selenium and coenzyme Q10 for four years. Even after twelve years we observed a significantly reduced risk for CV mortality in this group, as well as in subgroups of patients with diabetes, hypertension, ischemic heart disease or impaired functional capacity. The results thus validate the results obtained in the 10-year evaluation. The protective action was not confined to the intervention period, but persisted during the follow-up period. The mechanisms behind this effect remain to be fully elucidated, although various effects on cardiac function, oxidative stress, fibrosis and inflammation have previously been identified. Since this was a small study, the observations should be regarded as hypothesis-generating.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01443780.

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.

Supplementation with Selenium and Coenzyme Q10 Reduces Cardiovascular Mortality in Elderly with Low Selenium Status. A Secondary Analysis of a Randomised Clinical Trial

Background

Selenium is needed by all living cells in order to ensure the optimal function of several enzyme systems. However, the selenium content in the soil in Europe is generally low. Previous reports indicate that a dietary supplement of selenium could reduce cardiovascular disease but mainly in populations in low selenium areas. The objective of this secondary analysis of a previous randomised double-blind placebo-controlled trial from our group was to determine whether the effects on cardiovascular mortality of supplementation with a fixed dose of selenium and coenzyme Q10 combined during a four-year intervention were dependent on the basal level of selenium.

Methods

In 668 healthy elderly individuals from a municipality in Sweden, serum selenium concentration was measured. Of these, 219 individuals received daily supplementation with selenium (200 μg Se as selenized yeast) and coenzyme Q10 (200 mg) combined for four years. The remaining participants (n = 449) received either placebo (n = 222) or no treatment (n = 227). All cardiovascular mortality was registered. No participant was lost during a median follow-up of 5.2 years. Based on death certificates and autopsy results, all mortality was registered.

Findings

The mean serum selenium concentration among participants at baseline was low, 67.1 μg/L. Based on the distribution of selenium concentration at baseline, the supplemented group was divided into three groups; <65 μg/L, 65–85 μg/L, and >85 μg/L (45 and 90 percentiles) and the remaining participants were distributed accordingly. Among the non-treated participants, lower cardiovascular mortality was found in the high selenium group as compared with the low selenium group (13.0% vs. 24.1%; P = 0.04). In the group with the lowest selenium basal concentration, those receiving placebo or no supplementation had a mortality of 24.1%, while mortality was 12.1% in the group receiving the active substance, which was an absolute risk reduction of 12%. In the middle selenium concentration group a mortality of 14.0% in the non-treated group, and 6.0% in the actively treated group could be demonstrated; thus, there was an absolute risk reduction of 8.0%. In the group with a serum concentration of >85 μg/L, a cardiovascular mortality of 17.5% in the non-treated group, and 13.0% in the actively treated group was observed. No significant risk reduction by supplementation could thus be found in this group.

Conclusions

In this evaluation of healthy elderly Swedish municipality members, two important results could be reported. Firstly, a low mean serum selenium concentration, 67 μg/L, was found among the participants, and the cardiovascular mortality was higher in the subgroup with the lower selenium concentrations <65 μg/L in comparison with those having a selenium concentration >85 μg/L. Secondly, supplementation was cardio-protective in those with a low selenium concentration, ≤85 at inclusion. In those with serum selenium>85 μg/L and no apparent deficiency, there was no effect of supplementation. This is a small study, but it presents interesting data, and more research on the impact of lower selenium intake than recommended is therefore warranted.

Trial Registration

Clinicaltrials.gov NCT01443780

Relatively high mortality risk in elderly Swedish subjects with low selenium status

Background/Objectives:

The daily dietary intake of selenium (Se), an essential trace element, is still low in Sweden in spite of decades of nutritional information campaigns and the effect of this on the public health is presently not well known. The objective of this study was to determine the serum Se levels in an elderly Swedish population and to analyze whether a low Se status had any influence on mortality.

Subjects/Methods:

Six-hundred sixty-eight (n=668) elderly participants were invited from a municipality and evaluated in an observational study. Individuals were followed for 6.8 years and Se levels were re-evaluated in 98 individuals after 48 months. Clinical examination of all individuals included functional classification, echocardiography, electrocardiogram and serum Se measurement. All mortality was registered and endpoints of mortality were assessed by Kaplan–Meier plots, and Cox proportional hazard ratios adjusted for potential confounding factors were calculated.

Results:

The mean serum Se level of the study population (n=668) was 67.1 μg/l, corresponding to relatively low Se intake. After adjustment for male gender, smoking, ischemic heart disease, diabetes, chronic obstructive pulmonary disease and impaired heart function, persons with serum Se in the lowest quartile had 43% (95% confidence interval (CI): 1.02–2.00) and 56% (95% CI: 1.03–2.36) increased risk for all-cause and cardiovascular mortality, respectively. The result was not driven by inflammatory effects on Se concentration in serum.

Conclusion:

The mean serum Se concentration in an elderly Swedish population was 67.1 μg/l, which is below the physiological saturation level for several selenoprotein enzymes. This result may suggest the value of modest Se supplementation in order to improve the health of the Swedish population.

The role of selenium in human conception and pregnancy

Selenium (Se) is a trace element essential for the appropriate course of vital processes in the human body. It is also a constituent of the active center of glutathione peroxidase that protects cellular membranes against the adverse effects of H2O2 lipid peroxides. Epidemiological surveys have demonstrated that selenium deficiency in the body may contribute to an increased risk for certain neoplasmic diseases (including colonic carcinoma, gastric carcinoma, pulmonary carcinoma and prostate carcinoma), as well as diseases of the cardiovascular, osseous and nervous systems. Apart from its cancer prevention and antioxidative activities, selenium protects the body against detrimental effects of heavy metals and determines the proper functioning of the immunological system. Furthermore, selenium plays a significant role in the undisturbed functioning of the reproductive system. Many studies have addressed correlations between its intake and fertility as well as disorders of procreation processes. Selenium deficiencies may lead to gestational complications, miscarriages and the damaging of the nervous and immune systems of the fetus. A low concentration of selenium in blood serum in the early stage of pregnancy has been proved to be a predictor of low birth weight of a newborn. A deficiency of this element may also cause infertility in men by causing a deterioration in the quality of semen and in sperm motility. For this reason, supplementation in the case of selenium deficiencies in the procreation period of both women and men is of utmost significance.

Selenium status in patients with autoimmune and non-autoimmune thyroid diseases from four European countries

CONTEXT

Selenium supplementation has been suggested for Hashimoto thyroiditis and Graves' ophthalmopathy. Objective, Design: Our aim is to measure selenium status (p-Se, p-SePP), urine iodine (UI) levels and urine iodine/creatinine ratio (UI/C) in different thyroid diseases (n = 416) from four European countries and to compare the results between patients with and without thyroid autoimmunity.

RESULTS

p-Se and p-SePP showed positive correlation and did not correlate with UI/C. Also, these measurements were higher in patients from Italy in comparison with the other countries. Austria had the lowest UI/C ratios. Selenium deficiency exists in these four European countries. Selenium status was lower in patients with Hashimoto thyroiditis and Graves' disease in comparison with non-autoimmune thyroid disease patients and did not differ between autoimmune patients with or without thyroid peroxidase antibodies. The latter correlated positively with age.

CONCLUSIONS

Our findings suggest that Se supplementation might have a beneficial effect in autoimmune thyroid patients.

The impact of GPX1 on the association of groundwater selenium and depression: a Project FRONTIER study

BACKGROUND

Prior animal model and human-based studies have linked selenium concentrations to decreased risk for depression; however, this work has not focused on household groundwater levels or specific depressive symptoms. The current study evaluated the link between groundwater selenium levels and depression. We also sought to determine if a functional polymorphism in the glutathione peroxidase 1 (GPX1) gene impacted this link.

METHODS

We used a cross-sectional design to analyze data from 585 participants (183 men and 402 women) from Project FRONTIER, a study of rural health in West Texas. Residential selenium concentrations were estimated using Geospatial Information System (GIS) analyses. Linear regression models were created using Geriatric Depression Scale (GDS-30) total and subfactor scores as outcome variables and selenium concentrations as predictor variables. Analyses were re-run after stratification of the sample on GPX1 Pro198Leu genotype (rs1050454).

RESULTS

Selenium levels were significantly and negatively related to all GDS and subfactor scores accounting for up to 17% of the variance beyond covariates. Selenium was most strongly protective against depression among homozygous carriers of the C allele at the Pro198Leu polymorphism of the GPX1 gene. Analyses also point towards a gene-environmental interaction between selenium exposure and GPX1 polymorphism.

CONCLUSION

Our results support the link between groundwater selenium levels and decreased depression symptoms. These findings also highlight the need to consider the genetics of the glutathione peroxidase system when examining this relationship, as variation in the GPX1 gene is related to depression risk and significantly influences the protective impact of selenium, which is indicative of a gene-environment interaction.

Predicted dietary intake of selenium by the general adult population in Belgium

The total selenium content of about 800 food products purchased in Belgium was determined and combined with food records to determine the nutritional selenium status of Belgian people. The largest selenium concentrations (>1 mg kg(-1)) were found in Brazil nuts and offal, of which the consumption is limited. Usually consumed food groups with the highest selenium concentrations were fish and shellfish (0.2-0.9 mg kg(-1)), eggs, poultry meat, cheese, mushrooms and pasta (approximately 0.2 mg kg(-1)). The mean dietary selenium intake was calculated to be 60 µg day(-1), which is at the lower end but within the range recommended by the Superior Health Council in Belgium (60-70 µg day(-1)), and adequate according to the 55 µg day(-1) recommended by the Scientific Committee on Food (SCF) of the European Commission. The major sources of selenium intake are meat and meat products (31%), fish and shellfish (20%), pasta and rice (12%), and bread and breakfast cereals (11%).

Daily intake of selenium and concentrations in blood of residents of Riyadh City, Saudi Arabia

Concentrations of selenium (Se) in food from local markets of Riyadh, Kingdom of Saudi Arabia (KSA) were measured and daily intake calculated based on information from a questionnaire of foods eaten by healthy Saudis. The daily intake of Se was then compared to concentrations of Se in blood serum. Primary sources of Se in the diet of Saudis were as follows: meat and meat products (31%), egg (20.4%), cereals and cereal products (16%), legumes (8.7%), fruits (6.8%), milk and dairy products (2.0%), beverages (2%), sweets (1.8%), pickles (0.2%), and oil (0.02%). Daily intake of Se, estimated to be 93 μg Se/person/day, was slightly greater than that calculated from the Food and Agriculture Organization (FAO) food balance sheet for KSA, which was approximately 90 μg Se/person/day. The daily intake of Se by Saudis in Riyadh was greater than that of Australians or Dutch but less that of Canadians and Americans. There was a statistically significant correlation (R = +0.38, P < 0.05) between daily intake of Se and concentrations of Se in blood serum of Saudis in Riyadh. The mean concentration of Se in serum was 1.0 × 10(2) ± 30.5 μg Se/l. Taken together, the results suggest that the average Se intake and Se serum concentrations are within the known limits and recommendations, making it unlikely that Saudis are on average at risk of deficiency or toxicity.

Selenium supplementation in the critically ill

Selenium (Se) is an essential trace element with antioxidant, immunological, and anti-inflammatory properties, which are attributed to its presence in selenoproteins, as the 21st amino acid selenocysteine. These selenoenzymes are involved in redox signaling, antioxidant defense, thyroid hormone metabolism, and immune responses. Dietary intakes differ considerably between geographical regions, due to variability of the Se food content, leading to differences in dietary reference intakes and toxicity cautions. Critical illness with systemic inflammatory response syndrome (SIRS) is characterized by Se depletion with high morbidity and mortality. Se status correlates well with clinical outcome in SIRS and may be useful as an early predictor of survival. Several investigators have evaluated the benefits of Se supplementation for the critically ill, either as monotherapy or in an antioxidant micronutrient combination. Pharmaconutrition, with high-dose Se (from 500-1600 µg/d) involving an initial loading bolus, followed by continuous infusion, appears to be safe and efficacious, with evidence that it can improve clinical outcome by reducing illness severity, infectious complications, and decreasing mortality in the intensive care unit (ICU). We now have a clearer understanding of the pharmacokinetics of the initial and transient pro-oxidant effect of an intravenous bolus of selenite and the antioxidant effect of continuous infusion. Better biomarkers to ascertain optimum Se requirements for individual patients are now needed, and clinical practice guidelines need improvement. Nevertheless, sufficient evidence is available to consider initiating high-dose intravenous Se therapy routinely in critically ill SIRS patients, immediately on admission to the ICU.

Selenium and prostate cancer: systematic review and meta-analysis

BACKGROUND

Prostate cancer is a growing public health problem. Several human studies have shown a potentially protective effect of selenium, but the conclusions from published reports are inconsistent.

OBJECTIVE

The objective was to examine the evidence for relations between selenium intake, selenium status, and prostate cancer risk.

DESIGN

This was a systematic review and meta-analysis of randomized controlled trials, case-control studies, and prospective cohort studies. The World Cancer Research Fund/American Institute for Cancer Research Continuous Update Project database was searched up to September 2010. The studies included reported measurements of selenium intake or status (plasma, serum, or toenail selenium), assessments of prostate cancer cases (number of events), and the RR in the adult population. Meta-analyses were performed, and study quality, heterogeneity, and small study effects were assessed. Dose-response meta-analyses were used, with restricted cubic splines and fractional polynomials for nonlinear trends, to investigate the association between selenium status and prostate cancer risk.

RESULTS

Twelve studies with a total of 13,254 participants and 5007 cases of prostate cancer were included. The relation between plasma/serum selenium and prostate cancer in a nonlinear dose-response meta-analysis showed that the risk decreased with increasing plasma/serum selenium up to 170 ng/mL. Three high-quality studies included in the meta-analysis of toenail selenium and cancer risk indicated a reduction in prostate cancer risk (estimated RR: 0.29; 95% CI: 0.14, 0.61) with a toenail selenium concentration between 0.85 and 0.94 μg/g.

CONCLUSION

The relation between selenium status and decreased prostate cancer risk was examined over a relatively narrow range of selenium status; further studies in low-selenium populations are required.

Supra-physiological folic acid concentrations induce aberrant DNA methylation in normal human cells in vitro

The micronutrients folate and selenium may modulate DNA methylation patterns by affecting intracellular levels of the methyl donor S-adenosylmethionine (SAM) and/or the product of methylation reactions S-adenosylhomocysteine (SAH). WI-38 fibroblasts and FHC colon epithelial cells were cultured in the presence of two forms of folate or four forms of selenium at physiologically-relevant doses, and their effects on LINE-1 methylation, gene-specific CpG island (CGI) methylation and intracellular SAM:SAH were determined. At physiologically-relevant doses the forms of folate or selenium had no effect on LINE-1 or CGI methylation, nor on intracellular SAM:SAH. However the commercial cell culture media used for the selenium studies, containing supra-physiological concentrations of folic acid, induced LINE-1 hypomethylation, CGI hypermethylation and decreased intracellular SAM:SAH in both cell lines. We conclude that the exposure of normal human cells to supra-physiological folic acid concentrations present in commercial cell culture media perturbs the intracellular SAM:SAH ratio and induces aberrant DNA methylation.

Selenium in human health and disease

This review covers current knowledge of selenium in the environment, dietary intakes, metabolism and status, functions in the body, thyroid hormone metabolism, antioxidant defense systems and oxidative metabolism, and the immune system. Selenium toxicity and links between deficiency and Keshan disease and Kashin-Beck disease are described. The relationships between selenium intake/status and various health outcomes, in particular gastrointestinal and prostate cancer, cardiovascular disease, diabetes, and male fertility, are reviewed, and recent developments in genetics of selenoproteins are outlined. The rationale behind current dietary reference intakes of selenium is explained, and examples of differences between countries and/or expert bodies are given. Throughout the review, gaps in knowledge and research requirements are identified. More research is needed to improve our understanding of selenium metabolism and requirements for optimal health. Functions of the majority of the selenoproteins await characterization, the mechanism of absorption has yet to be identified, measures of status need to be developed, and effects of genotype on metabolism require further investigation. The relationships between selenium intake/status and health, or risk of disease, are complex but require elucidation to inform clinical practice, to refine dietary recommendations, and to develop effective public health policies.

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.

Blood selenium, glutathione peroxidase activity and antioxidant supplementation of subjects exposed to arsenic via drinking water

This work investigated serum selenium (Se) and glutathione peroxidase (GPx) levels in 25 Croatian subjects exposed to high levels of As from drinking water (median As level in urine: 620.74μg/g creatinine) and 25 controls (32.98μg/g creatinine). The exposed group had lower (p<0.001) median serum Se and GPx levels (Se: 82.34μg/l vs 59.02μg/l; GPx: 45.99U/g hemoglobin vs 38.38U/g hemoglobin). A subsample of 20 exposed subjects took part in a 2-month antioxidant supplementation trial which increased median GPx activity from 30.71 to 40.98U/g hemoglobin (p=0.041) and reduced total urinary As median from 680.15 to 501.96μg/g creatinine (p=0.051). The effect of selected catalase (-262C>T) and GPx1 (-593C>T) gene polymorphisms was also examined. The low Se status and GPx activity may heighten risk of adverse health effects, especially in genetically predisposed individuals. The outcome of antioxidant treatment indicates modulation of As metabolism and oxidative stress, relevance of which needs further research.

Serum levels of antioxidants (Zn, Cu, Se) in healthy volunteers living in Tehran

Zinc (Zn), copper (Cu), and selenium (Se) are well-known as essential trace elements. These elements attract a great interest, not only in the scientific world, but also in the public option. The aim of this study was to evaluate the serum Zn, Cu, and Se levels in healthy volunteers (60 females and 55 males) living in Tehran. The age (6-62 years) and sex of the subjects, as well as drug and tobacco consumption, were registered. The concentrations of these elements were determined by atomic absorption spectrometry. The serum levels of Zn, Cu, and Se in the normal population of Tehran was 0.89 +/- 0.16 mg/L, 0.95 +/- 0.20 mg/L, and 99.10 +/- 21.78 microg/L, respectively. There was no significant gender-related difference in serum Zn concentration (p < 0.15). However, a significant difference (p < 0.05) in both Cu and Se levels was observed between males and females.

Selenium in food and the human body: a review

Selenium levels in soil generally reflect its presence in food and the Se levels in human populations. Se food content is influenced by geographical location, seasonal changes, protein content and food processing. Periodic monitoring of Se levels in soil and food is necessary. Diet is the major Se source and approximately 80% of dietary Se is absorbed depending on the type of food consumed. Se bioavailability varies according to the Se source and nutritional status of the subject, being significantly higher for organic forms of Se. Se supplements can be beneficial for subjects living in regions with very low environmental levels of Se. Several strategies have been followed: (1) employment of Se-enriched fertilizers; (2) supplementation of farm animals with Se; (3) consumption of multimicronutrient supplements with Se. Nevertheless, detailed investigations of possible interactions between Se supplements and other food components and their influence on Se bioavailability are needed. Suppliers also need to provide more information on the specific type of Se used in supplements. In addition, research is lacking on the mechanisms through which Se is involved in hepatocyte damage during hepatopathies. Although Se potential as an antioxidant for the prevention of cardiovascular diseases (CVD) is promising, additional long-term intervention trials are necessary. As a result, indiscriminate Se supplements cannot be reliably recommended for the prevention of CVD in human beings. Some interesting findings reported an association of Se intake with a reduced prevalence and risk for prostate and colon cancer. However, random trials for other cancer types are inconclusive. As a final conclusion, the general population should be warned against the employment of Se supplements for prevention of hepatopathies, cardiovascular or cancer diseases, because benefits of Se supplementation are still uncertain, and their indiscriminate use could generate an increased risk of Se toxicity.

Selenium status of the Swiss population: assessment and change over a decade

A monitoring study of serum selenium concentration was carried out on healthy blood donors from different regions of Switzerland. With an overall mean serum concentration of 98 microg/L (n=1847), the selenium status of the healthy adults can be assessed as adequate. The lowest measured concentration of 62 microg/L denotes that the risk of a marginal selenium deficiency in the Swiss population is small. Compared to a similar study carried out in 1993, the status improved for both genders, although the increase is higher among women. It is noteworthy that the supplementation practice has increased during this period with ca. 2% of the population taking Se-micronutrients. No correlation between the age and the serum concentration is detected, even though the age-range was enlarged in this study to 18-68 years for the women and to 19-72 years for the men. The place of residence only marginally influences the selenium concentration, which implies a certain uniformity of the dietary habits between the various regions of the country.

Plasma selenium levels in healthy blood bank donors in the central-eastern part of Belgium

Graphite furnace atomic absorption spectrometry, with Zeeman background correction and after improved matrix modification, was used to measure the plasma selenium content of healthy blood bank donors in the central part of Belgium. The mean plasma selenium concentration of 80 men and 80 women was 79.7+/-4.4ng/mL with a range of 55.0-117.4ng/mL. There was no gender difference observed. Plasma selenium level was significantly highest for the adult group, aged 45-64 years, compared to the others, except the young adults (18-24 years). The mean plasma selenium concentration measured corresponded well with literature data for Belgium. The obtained values were found to be in the medium range, compared with recent literature values for the European countries.

Whole blood mercury and selenium concentrations in a selected Austrian population: does gender matter?

BACKGROUND

Data on mercury exposure of the Austrian population were inadequate. This study was performed to determine the causal factors underlying mercury exposure and selenium concentrations, and to estimate the gender-related health impacts.

METHODOLOGY

Venous blood samples of 78 women and 81 men were drawn at the Austrian Red Cross, Vienna. Mercury contents in acid-digested whole blood samples were measured after amalgam enrichment by CV-AAS, and selenium by AAS (heated quartz-cell) after hydrid formation.

RESULTS

The average total mercury blood content of Austrians was low (2.38+/-1.55 microgL(-1); N=152). Mercury and selenium concentrations were not different between the genders (P>0.05) but we observed discrepancies regarding the causal factors. Mercury levels in men were influenced not only by fish consumption but also by age, education level, and amalgam fillings, whereas in women, only the diet (fish/seafood, red wine consumption) determined blood mercury (P<0.05). Moreover, only the males indicated a depressive effect of dental amalgam on hematocrit (P<0.05). Regarding selenium, age and alcohol consumption led to lower concentrations in men, whereas a high-level education had the opposite effect; no determinant was found for women. For the whole study group, a significant effect of chronic disease on selenium levels could be detected (P<0.05). 18% of women and 13% of men showed marginal selenium deficiency (blood selenium<65 microgL(-1)). Selenium and mercury concentrations were not correlated.

CONCLUSIONS

Our results indicate the need to evaluate and integrate gender-related findings in metal toxicology and trace element research, because different causal factors require different preventive measures to reduce mercury exposure and the risk of low selenium concentrations. Future research is needed on the gender- and age-related differences in fish/seafood consumption habits, the modifications of mercury toxicokinetics through sex hormones, the selenium supply in Austria, and the clinical relevance of a low selenium status.