Exploring the association of metal mixture in blood to the kidney function and tumor necrosis factor alpha using machine learning methods

This research aimed to approach relationships between metal mixture in blood and kidney function, tumor necrosis factor alpha (TNF-α) by machine learning. Metals levels were measured by Inductively Couple Plasma Mass Spectrometry in blood from 421 participants. We applied K Nearest Neighbor (KNN), Naive Bayes classifier (NB), Support Vector Machines (SVM), random forest (RF), Gradient Boosting Decision Tree (GBDT), Categorical boosting (CatBoost), eXtreme Gradient Boosting (XGBoost), Whale Optimization-based XGBoost (WXGBoost) to identify the effect of plasma metals, TNF-α, and estimated glomerular filtration rate (eGFR by CKD-EPI equation). We conducted not only toxic metals, lead (Pb), arsenic (As), cadmium (Cd) but also included trace essential metals, selenium (Se), copper (Cu), zinc (Zn), cobalt (Co), to predict the interaction of TNF-α, TNF-α/white blood count, and eGFR. The high average TNF-α level group was observed among subjects with higher Pb, As, Cd, Cu, and Zn levels in blood. No associations were shown between the low and high TNF-α level group in blood Se and Co levels. Those with lower eGFR group had high Pb, As, Cd, Co, Cu, and Zn levels. The crucial predictor of TNF-α level in metals was blood Pb, and then Cd, As, Cu, Se, Zn and Co. The machine learning revealed that As was the major role among predictors of eGFR after feature selection. The levels of kidney function and TNF-α were modified by co-exposure metals. We were able to acquire highest accuracy of over 85% in the multi-metals exposure model. The higher Pb and Zn levels had strongest interaction with declined eGFR. In addition, As and Cd had synergistic with prediction model of TNF-α. We explored the potential of machine learning approaches for predicting health outcomes with multi-metal exposure. XGBoost model added SHAP could give an explicit explanation of individualized and precision risk prediction and insight of the interaction of key features in the multi-metal exposure.

Population status of selenium in Colombia and associated factors: a cross-sectional study

OBJECTIVES

This study aims to investigate the population status of selenium in Colombia and other associated factors.

METHODS

Cross-sectional study, in population of urban or rural origin (n=412). Main outcome measures were: median serum selenium, thyrotropin, the prevalence of and positivity of anti-thyroid peroxidase, anti-thyroglobulin, and anti-TSH receptor.

RESULTS

This study found that 96.6% of the subjects had normal selenium levels, and no significant associations were found between the population median of selenium and overweight/obesity, sociodemographic variables, age, goiter, and thyroid antibody positivity.

CONCLUSIONS

In Colombia, the population status of selenium is normal, and the geological characteristics may contribute to the state of selenium in this population. However, additional studies are required to evaluate the content of selenium in plants and other foods.

Gestational thyroid hormone concentrations and risk of attention-deficit hyperactivity disorder in the Norwegian Mother, Father and Child Cohort Study

BACKGROUND

Maternal thyroid function plays an important role in foetal brain development; however, little consensus exists regarding the relationship between normal variability in thyroid hormones and common neurodevelopmental disorders, such as attention-deficit hyperactivity disorder (ADHD).

OBJECTIVE

We sought to examine the association between mid-pregnancy maternal thyroid function and risk of clinically diagnosed ADHD in offspring.

METHODS

We conducted a nested case-control study in the Norwegian Mother, Father and Child Cohort Study. Among children born 2003 or later, we randomly sampled singleton ADHD cases obtained through linkage with the Norwegian Patient Registry (n = 298) and 554 controls. Concentrations of maternal triiodothyronine (T3), thyroxine (T4), T3-Uptake, thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPO-Ab) were measured in maternal plasma, collected at approximately 17 weeks' gestation. Indices of free T4 (FT4i) and free T3 (FT3i) were calculated. We used multivariable adjusted logistic regression to calculate odds ratios and accounted for missing covariate data using multiple imputation. We used restricted cubic splines to assess non-linear trends and provide flexible representations. We examined effect measure modification by dietary iodine and selenium intake. In sensitivity analyses, we excluded women with clinically significant thyroid disorders (n = 73).

RESULTS

High maternal T3 was associated with increased risk of ADHD (5th vs 1st quintile odds ratio  2.27, 95% confidence interval 1.21, 4.26). For FT4i, both the lowest and highest quintiles were associated with an approximate 1.6-fold increase in risk of ADHD, with similar trends found for T4. The FT4i association was modified by dietary iodine intake such that the highest risk strata were confined to the low intake group.

CONCLUSIONS

Both high and low concentrations of maternal thyroid hormones, although within population reference ranges, increase the risk of ADHD in offspring. Increased susceptibility may be found among women with low dietary intake of iodine and selenium.

Evaluation of Serum Selenium and Copper Levels with Inflammatory Cytokines and Indices of Oxidative Stress in Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) is a metabolic and multifactorial disease in which inflammatory markers, oxidative stress, and certain trace elements seem to have an essential role. This study investigated the relationship between serum selenium and copper level with inflammatory cytokines and oxidative stress in T2DM.In this case-control study, 30 patients with T2DM and 30 healthy individuals were selected. Serum levels of copper and selenium were measured by atomic absorption spectrometry, and TNF-α and IL-6 and oxidative stress markers were measured by ELISA. The SPSS v.22 was used for data analysis and the significance level is less than 5%.The mean age of patients was 52.9 ± 10.4 years, and the control group was 48.5 ± 10.4 years. In this study, 53.3% were female, and 46.7% were male. The levels of BMI (p = 0.002), systolic pressure (p = 0.034), insulin, selenium, malondialdehyde, and glutathione peroxidase (p = 0.0001; each), insulin resistance, copper, and superoxide dismutase, IL6, and TNF-α (p = 0.001; each) in T2DM were significantly higher than the control group. While levels of lipid profile, uric acid, creatinine, and diastolic pressure were not significantly different between the two groups. Selenium and copper are related to insulin resistance, and their increasing levels are associated with increased levels of markers of oxidative stress and inflammatory cytokines (p < 0.05).Increased levels of copper and selenium are associated with T2DM and this increase is also associated with increased levels of TNF-α, IL-6, and oxidative stress in T2DM. Therefore, controlling these markers can lead us to control this disease better.

Correlations of selenium and selenoprotein P with asymmetric dimethylarginine and lipid profile in patients with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is associated with an increased risk of cardiovascular diseases (CVD). Accumulating evidence has suggested that selenium (Se) is of importance for optimal function of the cardiovascular system. This study aimed to investigate the associations of selenium and selenoprotein P (SePP) with asymmetric dimethylarginine (ADMA) and lipid profile in women with PCOS.

METHODS

In this cross-sectional study, 125 females aged 18-45 years diagnosed with PCOS were recruited. An interviewer-administered questionnaire was applied to gather the relevant demographic characteristics, detailed clinical information, and lifestyle habits of participants. Fasting blood samples were obtained to measure biochemical parameters. Serum concentrations of total testosterone, sex hormone-binding globulin (SHBG), ADMA, and lipid profiles as well as anthropometric measurements were assessed across tertiles of serum Se and SePP concentrations.

RESULTS

There was a positive correlation between serum Se and SePP concentrations (r = 0.434, p < 0.001). Serum Se level was inversely correlated with ADMA (r = -0.21, p = 0.025) and TG (r = -0.17, p = 0.041) concentrations. There were also inverse correlations between SePP and ADMA (r = -0.34, p < 0.001), TG (r = -0.21, p = 0.019), and oxidized low density lipoprotein (ox-LDL) (r = -0.25, p = 0.007) levels. No significant relationship was found between serum Se and SePP concentrations with total cholesterol, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), apolipoprotein-A1 (Apo-A1), apolipoprotein-B (Apo-B100), total testosterone, SHBG, and free androgen index as well as anthropometric parameters (All p > 0.05).

CONCLUSION

The present study found that Se and SePP levels were inversely correlated with ADMA and TG concentrations as well as ox-LDL levels.

Blood cadmium, lead, manganese, mercury, and selenium levels in American Indian populations: The Strong Heart Study

BACKGROUND

Many American Indian (AI) communities are in areas affected by environmental contamination, such as toxic metals. However, studies assessing exposures in AI communities are limited. We measured blood metals in AI communities to assess historical exposure and identify participant characteristics associated with these levels in the Strong Heart Study (SHS) cohort.

METHOD

Archived blood specimens collected from participants (n = 2014, all participants were 50 years of age and older) in Arizona, Oklahoma, and North and South Dakota during SHS Phase-III (1998-1999) were analyzed for cadmium, lead, manganese, mercury, and selenium using inductively coupled plasma triple quadrupole mass spectrometry. We conducted descriptive analyses for the entire cohort and stratified by selected subgroups, including selected demographics, health behaviors, income, waist circumference, and body mass index. Bivariate associations were conducted to examine associations between blood metal levels and selected socio-demographic and behavioral covariates. Finally, multivariate regression models were used to assess the best model fit that predicted blood metal levels.

FINDINGS

All elements were detected in 100% of study participants, with the exception of mercury (detected in 73% of participants). The SHS population had higher levels of blood cadmium and manganese than the general U.S. population 50 years and older. The median blood mercury in the SHS cohort was at about 30% of the U.S. reference population, potentially due to low fish consumption. Participants in North Dakota and South Dakota had the highest blood cadmium, lead, manganese, and selenium, and the lowest total mercury levels, even after adjusting for covariates. In addition, each of the blood metals was associated with selected demographic, behavioral, income, and/or weight-related factors in multivariate models. These findings will help guide the tribes to develop education, outreach, and strategies to reduce harmful exposures and increase beneficial nutrient intake in these AI communities.

Serum BDNF and Selenium Levels in Elite Athletes Exposed to Blows

Background and Objectives: The study aimed to investigate the combined acute and long-term effects of exposure to blows and exercise on serum BDNF (brain-derived neurotrophic factor) and selenium levels. Materials and Methods: Serum BDNF and selenium levels were determined in 40 male elite athletes before and after vigorous exercise (training match) with a probability of exposure to blows and in 10 sedentary men subjected to exercise (Astrand running protocol). Results: Serum BDNF levels were found 11.50 ± 3.50 ng/mL before exercise and 14.02 ± 3.15 ng/mL after exercise in the athlete group (p = 0.02), and 12.18 ± 4.55 ng/ mL and 11.74 ± 2.48 ng/ mL before and after exercise in the sedentary group, respectively (p = 0.873). Serum BDNF (pre-exercise, baseline) levels were slightly lower in the athlete group than those in the sedentary group (11.50 ± 3.50 and 12.18 ± 4.55 ng/mL, respectively, p = 0.796). Pre-exercise serum selenium levels in athletes were significantly higher compared to those of sedentary participants (130.53 ± 36.79 and 95.51 ± 20.57 µg/L, respectively, p = 0.011). There was no difference in selenium levels after exercise (124.01 ± 29.96 µg/L) compared to pre-exercise (130.53 ± 36.79 µg/L) in the athlete group (p = 0.386). Similarly, there was no difference in selenium levels after exercise (113.28 ± 25.51 µg/L) compared to pre-exercise (95.51 ± 20.57 µg/L) in the sedentary group (p = 0.251). Conclusions: BDNF results show that even if athletes are exposed to blows, they may be protected from the long-term effects of blows thanks to the protective effect of their non-sedentary lifestyle. Regular exercise may have a protective effect on maintaining serum selenium levels in athletes even exposed to blows chronically.

Selenium and cancer risk: Wide-angled Mendelian randomization analysis

Evidence on the association between selenium and cancer risk is inconclusive. We conducted a Mendelian randomization study to examine the associations of selenium levels with 22 site-specific cancers and any cancer. Single nucleotide polymorphisms (SNPs) strongly associated with toenail and blood (TAB) and blood selenium levels in mild linkage disequilibrium (r2  < .3) were used as instrumental variables. Genetic associations of selenium-associated SNPs with cancer were obtained from the UK Biobank including a total of 59 647 cancer cases and 307 914 controls. Associations with P < .1 in UK Biobank were tested for replication in the FinnGen consortium comprising more than 180 000 individuals. The inverse-variance weighted method accounting for linkage disequilibrium was used to estimate the associations. Genetically predicted TAB selenium levels were not associated with the risk of the 22 site-specific cancers or any cancer (all 22 site-specific cancers). Similarly, we observed no strong association for genetically predicted blood selenium levels. However, genetically predicted blood selenium levels showed suggestive associations with risk of kidney cancer (odds ratio [OR] per one-unit increase in log-transformed levels: 0.83; 95% confidence interval [CI]: 0.67-1.03) and multiple myeloma (OR: 1.40; 95% CI: 1.02-1.93). The same direction of association for kidney cancer but not for multiple myeloma was observed in FinnGen. In the metaanalysis of UK Biobank and FinnGen, the OR of kidney cancer was 0.83 (95% CI: 0.69-1.00). Our study suggests that high selenium status may not prevent cancer development. The associations for kidney cancer and multiple myeloma need to be verified in well-powered studies.

Plasma Concentrations of Trace Elements Selenium and Cobalt During and After Coronary Artery Bypass Grafting Surgery

Trace elements selenium (Se) and cobalt (Co) are essential in the human body, and a correlation between Se and cardiac surgery has been suggested. We investigated the plasma concentrations of Se and Co during and after coronary artery bypass grafting (CABG) surgery under cardiopulmonary bypass (CPB). From December 2019 to January 2020, preoperative plasma samples from isolated first-time CABG patients (n=20; 10 males, 10 females) were prospectively collected post-anesthesia and before CPB (T1), 45 min after CPB started (T2), 90 min after CPB started (T3), and postoperative days 1 (T4), and day 4 (T5). The plasma concentrations of Se and Co were measured. The Se concentration was significantly decreased at T2 (105.24±4.08 vs. 68.56±2.42 μg/L, p<0.001) and T3 (105.24±4.08 vs. 80.41±3.40 μg/L, p<0.001). The Co concentration was significantly decreased at T4 (0.35±0.19 vs. 0.26±0.13 μg/L, p<0.01) and T5 (0.35±0.19 vs. 0.23±0.11 μg/L, p<0.001). Five patients developed atrial fibrillation (AF); there was no other operative mortality or major morbidity. This is the first report of alterations of plasma Se and Co concentrations during and after CABG surgery. Our results may indicate that Se supplementation before or during CABG and Co supplementation after CABG may become necessary for patients undergoing CABG.

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.

The Effect of Circulating Zinc, Selenium, Copper and Vitamin K1 on COVID-19 Outcomes: A Mendelian Randomization Study

Background & Aims: Previous results from observational, interventional studies and in vitro experiments suggest that certain micronutrients possess anti-viral and immunomodulatory activities. In particular, it has been hypothesized that zinc, selenium, copper and vitamin K1 have strong potential for prophylaxis and treatment of COVID-19. We aimed to test whether genetically predicted Zn, Se, Cu or vitamin K1 levels have a causal effect on COVID-19 related outcomes, including risk of infection, hospitalization and critical illness. Methods: We employed a two-sample Mendelian Randomization (MR) analysis. Our genetic variants derived from European-ancestry GWAS reflected circulating levels of Zn, Cu, Se in red blood cells as well as Se and vitamin K1 in serum/plasma. For the COVID-19 outcome GWAS, we used infection, hospitalization or critical illness. Our inverse-variance weighted (IVW) MR analysis was complemented by sensitivity analyses including a more liberal selection of variants at a genome-wide sub-significant threshold, MR-Egger and weighted median/mode tests. Results: Circulating micronutrient levels show limited evidence of association with COVID-19 infection, with the odds ratio [OR] ranging from 0.97 (95% CI: 0.87-1.08, p-value = 0.55) for zinc to 1.07 (95% CI: 1.00-1.14, p-value = 0.06)-i.e., no beneficial effect for copper was observed per 1 SD increase in exposure. Similarly minimal evidence was obtained for the hospitalization and critical illness outcomes with OR from 0.98 (95% CI: 0.87-1.09, p-value = 0.66) for vitamin K1 to 1.07 (95% CI: 0.88-1.29, p-value = 0.49) for copper, and from 0.93 (95% CI: 0.72-1.19, p-value = 0.55) for vitamin K1 to 1.21 (95% CI: 0.79-1.86, p-value = 0.39) for zinc, respectively. Conclusions: This study does not provide evidence that supplementation with zinc, selenium, copper or vitamin K1 can prevent SARS-CoV-2 infection, critical illness or hospitalization for COVID-19.

Prevalence of thyroid dysfunction in postpartum women with suboptimal iodine and selenium and adequate iron status

OBJECTIVE

Postpartum women experience thyroid dysfunction at twice the prevalence of the general population. Adequate biosynthesis of thyroid hormones depends on three trace elements: iodine, selenium and iron. This study aimed to investigate thyroid dysfunction within a cohort of women at six months postpartum in relation to iodine, selenium and iron status.

DESIGN

This cross-sectional study was part of an observational longitudinal cohort Mother and Infant Nutrition Investigation; data obtained at six months postpartum are reported.

SUBJECTS

Mother-infant pairs (n = 87) were recruited at three months postpartum and followed up at six months postpartum (n = 78).

MEASUREMENTS

Thyroid hormones (free triiodothyronine, free thyroxine, thyroid-stimulating hormone) and thyroid peroxidase antibodies were measured. Urinary iodine concentration, breast milk iodine concentration, serum thyroglobulin, plasma selenium, serum ferritin and serum soluble transferrin receptors were determined. Nonparametric data were expressed as median (25th, 75th percentile).

RESULTS

Thyroid dysfunction was found in 18% of women, and 4% of women had iron deficiency. Median urinary iodine concentration was 85 (43, 134) µg/L, median breast milk iodine concentration was 59 (39, 109) µg/L, and median serum thyroglobulin at 11.4 (8.6, 18.6) µg/L, indicating iodine deficiency. Median plasma selenium concentration was 105.8 (95.6, 115.3) µg/L. Women with marginally lower plasma selenium concentration were 1.12% times more likely to have abnormal TSH concentrations (p = .001).

CONCLUSIONS

There was a high prevalence of thyroid dysfunction. Plasma selenium concentration was the only significant predictor of the likelihood that women had thyroid dysfunction within this cohort, who were iodine deficient and mostly had adequate iron status. Strategies are required to improve both iodine and selenium status to better support maternal thyroid function.

Increased serum selenium levels are associated with reduced risk of advanced liver fibrosis and all-cause mortality in NAFLD patients: National Health and Nutrition Examination Survey (NHANES) III

INTRODUCTION AND OBJECTIVES

Selenium supplementation has been shown to have therapeutic value in chronic liver disease. We aimed to investigate the association between serum selenium, severity of liver fibrosis, and mortality in patients with Nonalcoholic Fatty Liver Disease (NAFLD).

PATIENTS OR MATERIAL AND METHODS

A total of 33,944 patients were identified from the Third National Health and Nutrition Examination Survey. NAFLD was diagnosed by hepatic ultrasound after the exclusion of other forms of liver diseases. The severity of liver fibrosis was determined by NAFLD Fibrosis Score >0.676. Multivariate logistic regression analysis was used to investigate the relationship between serum selenium level and liver fibrosis. Association between serum selenium and all-cause mortality in NAFLD patients was also evaluated.

RESULTS

Multivariate logistic regression analysis demonstrated odds ratio of advanced liver fibrosis (NFS > 0.676) was significantly reduced with increasing serum selenium levels; OR 0.55, [95% CI 0.32-0.94] in the highest selenium quartile. On stratification analysis, the following populations had a significantly reduced risk of advanced liver fibrosis: non-Hispanic white = OR 0.41 [0.24,0.68]; female = OR 0.32 [0.15-0.66] and age >47 = OR 0.47 [0.28-0.79]. The relationship was significant regardless of BMI as noted by BMI ≤ 30 Kg/m2= OR 0.42 [0.19-0.91] and BMI > 30 Kg/m2=OR 0.52 [0.28-0.97]. Hazard ratio for all-cause mortality was HR 0.72 [0.56-0.95].

CONCLUSIONS

The risk of advanced liver fibrosis is inversely associated with serum selenium levels, particularly in older patients, Caucasians, and females. All-cause mortality decreased with increased selenium levels. Selenium may play a role in the prevention of liver fibrosis in NAFLD.

Course and Survival of COVID-19 Patients with Comorbidities in Relation to the Trace Element Status at Hospital Admission

Selenium (Se) and zinc (Zn) are essential trace elements needed for appropriate immune system responses, cell signalling and anti-viral defence. A cross-sectional observational study was conducted at two hospitals in Ghent, Belgium, to investigate whether Se and/or Zn deficiency upon hospital admission correlates to disease severity and mortality risk in COVID-19 patients with or without co-morbidities. Trace element concentrations along with additional biomarkers were determined in serum or plasma and associated to disease severity and outcome. An insufficient Se and/or Zn status upon hospital admission was associated with a higher mortality rate and a more severe disease course in the entire study group, especially in the senior population. In comparison to healthy European adults, the patients displayed strongly depressed total Se (mean ± SD: 59.2 ± 20.6 vs. 84.4 ± 23.4 µg L⁻¹) and SELENOP (mean ± SD: 2.2 ± 1.9 vs. 4.3 ± 1.0 mg L⁻¹) concentrations at hospital admission. Particularly strong associations were observed for death risk of cancer, diabetes and chronic cardiac disease patients with low Se status, and of diabetes and obese patients with Zn deficiency. A composite biomarker based on serum or plasma Se, SELENOP and Zn at hospital admission proved to be a reliable tool to predict severe COVID-19 course and death, or mild disease course. We conclude that trace element assessment at hospital admission may contribute to a better stratification of patients with COVID-19 and other similar infectious diseases, support clinical care, therapeutic interventions and adjuvant supplementation needs, and may prove of particular relevance for patients with relevant comorbidities.

Genetically predicted selenium is negatively associated with serum TC, LDL-C and positively associated with HbA1C levels

BACKGROUND & AIMS

Pervious epidemiological evidence on the associations of selenium, zinc with lipid profile and glycemic indices was contradictory. The aim of this study was to investigate whether selenium and zinc were casually associated with lipid profile and glycemic indices using mendelian randomization (MR) analysis.

METHOD

A two-sample MR was used to evaluate the causal-effect estimations. Summary statistics for selenium, zinc, lipids and glycemic indices were retrieved from previous large-scale genome-wide association study (GWAS). Single nucleotide polymorphisms (SNPs) that independently and strongly associated with the selenium and zinc were selected as the instrumental variables. The casual estimates were calculated using inverse variance weighted method (IVW), with weighted median, MR-Egger, and MR-PRESSO test as sensitivity analysis, respectively.

RESULTS

In the standard IVW analysis, per SD increment in selenium was associated with an 0.077 mmol/L decrease of TC (95 %CI: -0.102,-0.052) and 0.074 mmol/L of LDL-C (95 %CI: -0.1,-0.048). Suggestive casual associations were found between selenium and insulin or HbA1c. With IVW method, per SD increase in selenium was associated with an 0.023 mmol/L increase of insulin (95 %CI: 0.001,0.045), and an 0.013 mmol/L increase of HbA1c (95 %CI: 0.003,0.023). The results were robust in the sensitivity analysis. Zinc was not casually associated with any of lipid and glycemic markers.

CONCLUSION

Our MR analysis provides evidence of the potential causal effect of Se on beneficial lipid profile, including decreased TC and LDL-C. Furthermore, suggestive casual evidence was suggested between Se and increased serum HbA1c levels. Careful consideration is required for the protective effects of Se supplementation. No casual-effect association was found between Zn and any indices of the lipid and glucose parameters.

Comparison of external calibration and isotope dilution LC-ICP-MS/MS for quantitation of oxytocin and its selenium analogue in human plasma

In the present study, a method for quantitation of the pharmaceutical peptide oxytocin (OT) and its diselenide-containing analogue (SeOT) in human plasma was developed using gradient elution LC-ICP-MS/MS. Plasma samples were precipitated with acetonitrile containing 1.0% TFA in a volume ratio of 1+3 (sample+precipitation agent) before analysis. Post-column isotope dilution analysis (IDA) was applied for quantitation and was compared with external calibration. Both calibration methods appeared to be fit for purpose regarding figures of merit including linearity, precision, LOD, LOQ and recovery. Analysis of OT and SeOT showed that selenium-based analysis is considerably more sensitive and selective compared to the sulfur-based analysis. Despite the relatively simpler setup of external calibration, IDA can be advantageous because it compensates for instrument drift and changes in organic solvent concentration. The method was applied for a stability study showing the degradation of OT and SeOT in plasma. The degradation of SeOT was faster than the degradation of OT in plasma. Thus, possible stability effects should be considered before replacing a disulfide bridge with a diselenide bridge or introducing a diselenide label in a potential drug.

Can selenium-enriched spirulina supplementation ameliorate sepsis outcomes in selenium-deficient animals?

In intensive care units, sepsis is the first cause of death. In this pathology, inflammation and oxidative status play a crucial role in patient outcomes. Interestingly, 92% of septic patients exhibit low selenium plasma concentrations (a component of antioxidant enzymes). Moreover, Spirulina platensis, a blue-green algae, demonstrated anti-inflammatory effects. In this context, the main purpose of our study was to analyze the effect of a selenium-enriched spirulina after a selenium deficiency on sepsis outcome in rats. Sixty-four rats were fed 12 weeks with a selenium-deficient food. After 8 weeks, rats were supplemented (via drinking water) for 4 weeks with sodium selenite (Se), spirulina (Spi), or selenium-enriched spirulina (SeSp). Sepsis was then induced by cecal ligature and puncture, and survival duration was observed. The plasma selenium concentration was measured by ICPMS. Expression of GPx1 and GPx3 mRNA was measured by RT-PCR. Blood parameters (lactates and HCO3- concentrations, pH, PO2 , and PCO2 ) were analyzed at 0, 1, and 2 h as well as inflammatory cytokines (IL-6, TNF-α, IL-10). Sodium selenite and SeSP supplementations restored plasma selenium concentration prior to sepsis. The survival duration of SeSP septic rats was significantly lower than that of selenium-supplemented ones. Gpx1 mRNA was increased after a selenium-enriched spirulina supplementation while Gpx3 mRNA levels remained unchanged. Furthermore, sodium selenite prevented sepsis-induced acidosis. Our results show that on a basis of a Se deficiency, selenium-enriched spirulina supplementations significantly worsen sepsis outcome when compared to Se supplementation. Furthermore, Se supplementation but not selenium-enriched spirulina supplementation decreased inflammation and restored acid-base equilibrium after a sepsis induction.

Clinical Significance of Micronutrient Supplementation in Critically Ill COVID-19 Patients with Severe ARDS

The interplay between inflammation and oxidative stress is a vicious circle, potentially resulting in organ damage. Essential micronutrients such as selenium (Se) and zinc (Zn) support anti-oxidative defense systems and are commonly depleted in severe disease. This single-center retrospective study investigated micronutrient levels under Se and Zn supplementation in critically ill patients with COVID-19 induced acute respiratory distress syndrome (ARDS) and explored potential relationships with immunological and clinical parameters. According to intensive care unit (ICU) standard operating procedures, patients received 1.0 mg of intravenous Se daily on top of artificial nutrition, which contained various amounts of Se and Zn. Micronutrients, inflammatory cytokines, lymphocyte subsets and clinical data were extracted from the patient data management system on admission and after 10 to 14 days of treatment. Forty-six patients were screened for eligibility and 22 patients were included in the study. Twenty-one patients (95%) suffered from severe ARDS and 14 patients (64%) survived to ICU discharge. On admission, the majority of patients had low Se status biomarkers and Zn levels, along with elevated inflammatory parameters. Se supplementation significantly elevated Se (p = 0.027) and selenoprotein P levels (SELENOP; p = 0.016) to normal range. Accordingly, glutathione peroxidase 3 (GPx3) activity increased over time (p = 0.021). Se biomarkers, most notably SELENOP, were inversely correlated with CRP (r_s = −0.495), PCT (r_s = −0.413), IL-6 (r_s = −0.429), IL-1β (r_s = −0.440) and IL-10 (r_s = −0.461). Positive associations were found for CD8⁺ T cells (r_s = 0.636), NK cells (r_s = 0.772), total IgG (r_s = 0.493) and PaO₂/FiO₂ ratios (r_s = 0.504). In addition, survivors tended to have higher Se levels after 10 to 14 days compared to non-survivors (p = 0.075). Sufficient Se and Zn levels may potentially be of clinical significance for an adequate immune response in critically ill patients with severe COVID-19 ARDS.

Genetically predicted circulating concentrations of micronutrients and risk of colorectal cancer among individuals of European descent: a Mendelian randomization study

BACKGROUND

The literature on associations of circulating concentrations of minerals and vitamins with risk of colorectal cancer is limited and inconsistent. Evidence from randomized controlled trials (RCTs) to support the efficacy of dietary modification or nutrient supplementation for colorectal cancer prevention is also limited.

OBJECTIVES

To complement observational and RCT findings, we investigated associations of genetically predicted concentrations of 11 micronutrients (β-carotene, calcium, copper, folate, iron, magnesium, phosphorus, selenium, vitamin B-6, vitamin B-12, and zinc) with colorectal cancer risk using Mendelian randomization (MR).

METHODS

Two-sample MR was conducted using 58,221 individuals with colorectal cancer and 67,694 controls from the Genetics and Epidemiology of Colorectal Cancer Consortium, Colorectal Cancer Transdisciplinary Study, and Colon Cancer Family Registry. Inverse variance-weighted MR analyses were performed with sensitivity analyses to assess the impact of potential violations of MR assumptions.

RESULTS

Nominally significant associations were noted for genetically predicted iron concentration and higher risk of colon cancer [ORs per SD (ORSD): 1.08; 95% CI: 1.00, 1.17; P value = 0.05] and similarly for proximal colon cancer, and for vitamin B-12 concentration and higher risk of colorectal cancer (ORSD: 1.12; 95% CI: 1.03, 1.21; P value = 0.01) and similarly for colon cancer. A nominally significant association was also noted for genetically predicted selenium concentration and lower risk of colon cancer (ORSD: 0.98; 95% CI: 0.96, 1.00; P value = 0.05) and similarly for distal colon cancer. These associations were robust to sensitivity analyses. Nominally significant inverse associations were observed for zinc and risk of colorectal and distal colon cancers, but sensitivity analyses could not be performed. None of these findings survived correction for multiple testing. Genetically predicted concentrations of β-carotene, calcium, copper, folate, magnesium, phosphorus, and vitamin B-6 were not associated with disease risk.

CONCLUSIONS

These results suggest possible causal associations of circulating iron and vitamin B-12 (positively) and selenium (inversely) with risk of colon cancer.

Risk of breast cancer in relation to dietary intake of selenium and serum selenium as a marker of dietary intake: a prospective cohort study within The Malmö Diet and Cancer Study

Purpose

Selenium has been suggested to be protective against breast cancer, but the evidence remains inconclusive. Hence, it is important to further examine the potential protective effect. This prospective cohort study investigates pre-diagnostic selenium intake in relation to breast cancer risk. In addition, we analyze serum selenium as a marker of dietary intake.

Methods

This study includes 17,035 women in the Malmö Diet and Cancer cohort. Dietary assessment and serum samples were collected at baseline (1991–1996). During 344,584 person-years of follow-up, 1,427 incident cases were retrieved. Cox regression analysis examined breast cancer risks adjusted for potential confounding factors. In addition, odds ratios (ORs) were estimated for 1186 cases and an equal number of controls in relation to quartiles (Q) of selenium intake and groups consisting of a combination of intake and serum selenium levels.

Results

No overall association between selenium intake, or a combination of intake and serum levels, and breast cancer risk was found. The adjusted relative risk for breast cancer in selenium intake Q4 versus Q1 was 0.96 (0.83–1.12) (P_trend = 0.65). Similarly, adjusted the OR for breast cancer in selenium intake for Q4 versus Q1 was 0.97 (0.76–1.23). The kappa value, 0.096 (p = 0.001), showed poor agreement between serum selenium and selenium intake.

Conclusion

Our findings suggest that there is no overall association between selenium intake, or a combination of intake and serum levels, and breast cancer risk. Finally, our results showed a poor correlation between estimated selenium intake and serum selenium.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10552-021-01433-1.

Evaluation of Serum Selenium Status by Age and Gender: A Retrospective Observational Cohort Study in Western Romania

Selenium, residing in a series of selenoproteins, plays an important role in both female and male reproductive function. Of particular significance for reproduction is the antioxidant glutathione peroxidase (GPx), a main selenoenzyme, whose level is regulated by the availability of Se in the body. We hypothesized that changes in Se status, closely related to GPx activity, would result in an increased risk of reproductive dysfunction in individuals. We retrospectively investigated the serum selenium (SeS) concentrations of 1264 apparently healthy people, aged 16–89 years, from Western Romania. The general analysis revealed a non-normal SeS distribution with a median SeS of 100.26 ± 18.32 μg/L and a significant difference in SeS levels between age groups. The analysis of the young group (16–35 years) revealed that up to 50% of individuals did not reach the SeS threshold corresponding to maximum GPx activity (80 μg/L), and a significant imbalance between the genders was apparent when looking at SeS values outside the range. Our results correlated with the general diminished reproductive ability registered in Romania during the last few years. Serum selenium content proves to offer a proper reflection of the fertility competence of the young population, and its monitoring is important for guiding dietary adjustments and attaining normal reproductive function.

Association Between Serum Selenium Level and Subclinical Mastitis in Dairy Cattle

Selenium is an important element in nutrition, showing great potential in the udder health of dairy cattle and in the control of subclinical mastitis. However, there are few studies on selenium and subclinical mastitis in cows, and the correlation is not clear. A trial was designed to investigate the association between serum selenium levels and the immune and antioxidant capacity of dairy cattle with subclinical mastitis. Fifty cattle in early lactation with similar background information were selected randomly from an intensive dairy farm. Blood samples were collected for the detection of serum selenium levels by ICP-optic emission spectrometer. The cattle were divided into a low-selenium group (< 0.05 mg/L) and three normal selenium groups with different serum selenium levels (0.05-0.08 mg/L). The somatic cell count, immune indexes, and other indexes in the milk of each group were detected. The somatic cell count was found to be negatively correlated with serum selenium level. GSH-Px had a low positive correlation and IL-6 had a low negative correlation with serum selenium level. With a serum glutathione peroxidase < 148 U/L and IL-6 > 451 pg/mL, the risk of subclinical mastitis in dairy cattle increased.

Low Serum Levels of Selenium, Zinc, Iron, and Zinc/Copper Ratio in an Endemic Region of Cutaneous Leishmaniasis in Southwest Iran

Leishmaniasis is a widespread tropical infection; cutaneous leishmaniasis (CL) is the most common form of this disease known to cause significant morbidity. Trace metals, including selenium, zinc, iron, and copper, are required for the activity of several enzymes involved in immune system responses. The aim of this research was to measure the serum levels of selenium (Se), zinc (Zn), copper (Cu), iron (Fe), and Zn/Cu ratio in patients with CL. In this case-control study, 80 patients with CL and 80 healthy volunteers (not exposed to CL) from a CL endemic region in southwest Iran agreed to participate. Both clinical and parasitological verifications were made to include each subject as a CL-positive case. A questionnaire was completed for each participant which included the following criteria: age (year), height (cm), weight (kg), body mass index (kg/m²), and duration of disease (day). The biochemical assays were performed according to the standard protocols, and the values of Zn, Cu, Se, and Fe were expressed in micrograms per deciliter (μg/dl). All results were expressed as mean ± standard deviation (SD), and the statistical significance level was defined to be less than 0.05 (P < 0.05). There were no statistically significant differences in terms of mean values of age, body weight, height, and body mass index between CL patients and the control group (P > 0.05). The mean ± SD concentrations of Zn, Fe, and Se in the control group were found to be 118.87 ± 6.35 μg/dl, 123.00 ± 8.40 μg/dl, and 11.26 ± 1.88 μg/dl, respectively. These trace elements (TEs) were statistically lower (P < 0.001) in patients with CL (case group) with values of 83.05 ± 7.32 μg/dl for Zn, 86.51 ± 10.09 μg/dl for Fe, and 3.83 ± 1.20 μg/dl for Se. We have also observed that serum levels of Cu in CL-positive group were significantly higher than in the controls (P < 0.001). Furthermore, CL patients had significantly lower Zn/Cu ratio than controls (0.63 ± 0.05 μg/dl vs. 1.11 ± 0.10; P < 0.001). The alternation in serum levels of TEs may be a part of the defense strategy of the organism. Based on these results, it can be suggested that serum levels of these TEs can be a useful marker to estimate the prognosis of CL infection.

Do Only Calcium and Vitamin D Matter? Micronutrients in the Diet of Inflammatory Bowel Diseases Patients and the Risk of Osteoporosis

Osteoporosis is one of the most common extraintestinal complications among patients suffering from inflammatory bowel diseases. The role of vitamin D and calcium in the prevention of a decreased bone mineral density is well known, although other nutrients, including micronutrients, are also of extreme importance. Despite the fact that zinc, copper, selenium, iron, cadmium, silicon and fluorine have not been frequently discussed with regard to the prevention of osteoporosis, it is possible that a deficiency or excess of the abovementioned elements may affect bone mineralization. Additionally, the risk of malnutrition, which is common in patients with ulcerative colitis or Crohn's disease, as well as the composition of gut microbiota, may be associated with micronutrients status.

Dietary Habits, Selenium, Copper, Zinc and Total Antioxidant Status in Serum in Relation to Cognitive Functions of Patients with Alzheimer's Disease

Oxidative stress plays a crucial role in the neurodegenerative process and can impair cognitive functions. In the prevention of Alzheimer's disease (AD), an adequate consumption of dietary antioxidants may be a major factor. The objective of the study was to estimate selenium (Se), copper (Cu), zinc (Zn), and total antioxidant status (TAS) in the serum of patients with AD in relation to their cognitive functions and dietary habits. A total of 110 patients (aged 54-93 years) with early or moderate AD, as well as 60 healthy people (aged 52-83 years) were studied. The severity of the disease was assessed using the mini-mental state examination (MMSE) scale. Food-frequency questionnaires were implemented to collect the dietary data. The concentrations of Se, Cu and Zn in the sera were determined by the atomic absorption spectrometry method. TAS was estimated spectrophotometrically using ready-made kits (Randox). Significantly lower concentrations of Se, Zn and TAS, and higher Cu:Zn ratio in the serum of patients with AD, compared to healthy people, were observed. A low correlation between the MMSE score and TAS in the serum of AD patients and significantly higher MMSE values in patients with TAS above the reference range were also noted. In patients with serum Cu concentration above the norm, significantly lower MMSE values were found. Selected dietary habits such as the frequency of consumption of various food products had a significant impact on the concentration of the assessed parameters in the serum of people with AD.

Association of dietary and serum selenium concentrations with glucose level and risk of diabetes mellitus: A cross sectional study of national health and nutrition examination survey, 1999-2006

BACKGROUND

The associations among dietary selenium intake, serum selenium concentration, plasma glucose and glycosylated hemoglobin levels, and diabetes risk remain controversial. This study aimed to evaluate these associations in adults from the United States.

METHODS

We conducted a cross-sectional study of participants aged 18 years and older who participated in the National Health and Nutrition Examination Survey. Between 1999 and 2006, a total of 41,474 participants were initially included in this study. Multivariable linear or logistic regression analysis was used to investigate the association between dietary selenium intake and serum selenium concentrations, glucose level, and diabetes risk.

RESULTS

The average age of the participants was 30.32 ± 23.95 years, and 48.72 % were men. Their mean dietary selenium intake and mean serum selenium concentration were 98 ± 55 μg per day and 129 ± 22 ng/mL, respectively. Compared with t he lowest quartile of dietary selenium intake, the highest quartile was associated with elevated plasma glucose levels (β = 2.412, 95 % confidence interval [CI]: 0.420, 4.403, P = 0.018), glycosylated hemoglobin levels (β = 0.080, 95 % CI: 0.041, 0.119, P < 0.001), and diabetes risk (odds ratio [OR] = 2.139, 95 % CI: 1.763, 2.596, P < 0.001). Higher serum selenium was also associated with increased plasma glucose levels (β = 12.454, 95 % CI: 4.122, 20.786, P = 0.003) and glycosylated hemoglobin levels (β = 0.326, 95 % CI: 0.187, 0.465, P < 0.001). A generalized additive model with a spline curve suggested a nonlinear relationship between dietary selenium intake, serum selenium and glucose levels, and diabetes risk.

CONCLUSIONS

Dietary selenium intake and serum selenium were positively associated with elevated levels of plasma glucose and glycosylated hemoglobin, and the relationships were nonlinear. Additional selenium supplementation for patients with diabetes may not be recommended.

Selenium Kinetics in Humans Change Following 2 Years of Supplementation With Selenomethionine

BACKGROUND

Selenium (Se) is a nutritionally essential trace element and health may be improved by increased Se intake. Previous kinetic studies have shown differences in metabolism of organic vs. inorganic forms of Se [e.g., higher absorption of selenomethionine (SeMet) than selenite (Sel), and more recycling of Se from SeMet than Sel]. However, the effects on Se metabolism after prolonged Se supplementation are not known.

OBJECTIVE

To determine how the metabolism and transport of Se changes in the whole-body in response to Se-supplementation by measuring Se kinetics before and after 2 years of Se supplementation with SeMet.

METHODS

We compared Se kinetics in humans [n = 31, aged 40 ± 3 y (mean ± SEM)] studied twice after oral tracer administration; initially (PK1), then after supplementation for 2 y with 200 µg/d of Se as selenomethionine (SeMet) (PK2). On each occasion, we administered two stable isotope tracers of Se orally: SeMet, the predominant food form, and selenite (Na₂⁷⁶SeO_3, or Sel), an inorganic form. Plasma and RBC were sampled for 4 mo; urine and feces were collected for the initial 12 d of each period. Samples were analyzed for tracers and total Se by isotope dilution GC-MS. Data were analyzed using a compartmental model, we published previously, to estimate fractional transfer between pools and pool masses in PK2.

RESULTS

We report that fractional absorption of SeMet or Sel do not change with SeMet supplementation and the amount of Se absorbed increased. The amount of Se excreted in urine increases but does not account for all the Se absorbed. As a result, there is a net incorporation of SeMet into various body pools. Nine of the 11 plasma pools doubled in PK2; two did not change. Differences in metabolism were observed for SeMet and Sel; RBC uptake increased 247% for SeMet, urinary excretion increased from two plasma pools for Sel and from two different pools for SeMet, and recycling to liver/tissues increased from one plasma pool for Sel and from two others for SeMet. One plasma pool increased more in males than females in PK2.

CONCLUSIONS

Of 11 Se pools identified kinetically in human plasma, two did not increase in size after SeMet supplementation. These pools may be regulated and important during low Se intake.

Low serum selenium in pregnancy is associated with reduced T3 and increased risk of GDM

Thyroid disorders are the most common endocrine disorders affecting women commencing pregnancy. Thyroid hormone metabolism is strongly influenced by selenium status; however, the relationship between serum selenium concentrations and thyroid hormones in euthyroid pregnant women is unknown. This study investigated the relationship between maternal selenium and thyroid hormone status during pregnancy by utilizing data from a retrospective, cross-sectional study (Maternal Outcomes and Nutrition Tool or MONT study) with cohorts from two tertiary care hospitals in South East Queensland, Australia. Pregnant women (n = 206) were recruited at 26-30 weeks gestation and serum selenium concentrations were assessed using inductively coupled plasma mass spectrometry. Thyroid function parameters were measured in serum samples from women with the lowest serum selenium concentrations (51.2 ± 1.2 µg/L), women with mean concentrations representative of the entire cohort (78.8 ± 0.4 µg/L) and women with optimal serum selenium concentrations (106.9 ± 2.3 µg/L). Women with low serum selenium concentrations demonstrated reduced fT3 levels (P < 0.05) and increased TPOAb (P < 0.01). Serum selenium was positively correlated with fT3 (P < 0.05) and negatively correlated with TPOAb (P < 0.001). Serum fT4 and thyroid-stimulating hormone (TSH) were not different between all groups, though the fT4/TSH ratio was increased in the low selenium cohort (P < 0.05). Incidence of pregnancy disorders, most notably gestational diabetes mellitus, was increased within the low serum selenium cohort (P < 0.01). These results suggest selenium status in pregnant women of South East Queensland may not be adequate, with possible implications for atypical thyroid function and undesirable pregnancy outcomes.

Co-exposure of serum calcium, selenium and vanadium is nonlinearly associated with increased risk of type 2 diabetes mellitus in a Chinese population

BACKGROUND

Metals play an important role in type 2 diabetes mellitus (T2DM). This study aimed to explore the association of T2DM risk with single metal exposure and multi-metal co-exposure.

METHODS

A case-control study with 223 T2DM patients and 302 controls was conducted. Serum concentrations of 19 metals were determined by inductively coupled plasma mass spectrometry (ICP-MS). Those metals with greater effects were screened out and co-exposure effects of metals were assessed by least absolute shrinkage and selection operator (LASSO) regression.

RESULTS

Serum calcium (Ca), selenium (Se) and vanadium (V) were found with greater effects. Higher levels of Ca and Se were associated with increased T2DM risk (OR = 2.23, 95%CI: 1.38-3.62, P_trend = 0.002; OR = 3.16, 95%CI: 1.82-5.50, P_trend < 0.001), but higher V level was associated with decreased T2DM risk (OR = 0.58, 95%CI: 0.34-0.97, P_trend < 0.001). Serum Ca and V concentrations were nonlinearly associated with T2DM risk (P_overall < 0.001, P_nonliearity < 0.001); however, Se concentration was linearly associated with T2DM risk (P_overall < 0.001, P_nonliearity = 0.389). High co-exposure score of serum Ca, Se and V was associated with increased T2DM risk (OR = 3.50, 95%CI: 2.08-5.89, P_trend < 0.001) as a non-linear relationship (P_overall < 0.001, P_nonliearity = 0.003).

CONCLUSIONS

This study suggest that higher levels of serum Ca and Se were associated with increased T2DM risk, but higher serum V level was associated with decreased T2DM risk. Moreover, co-exposure of serum Ca, Se and V was nonlinearly associated with T2DM risk, and high co-exposure score was positively associated with T2DM risk.

Alcohol Consumption Moderated the Association Between Levels of High Blood Lead or Total Urinary Arsenic and Bone Loss

Metal exposure and lifestyle are important risk factors for osteoporosis. Our study aimed to investigate the association between red blood cell lead and cadmium, total urinary arsenic, and plasma selenium levels and bone mineral density (BMD). In addition, we explored whether alcohol and coffee consumption modified the association between BMD and metals and metalloids. In total, 437 participants who underwent adult or senile physical examinations were recruited. Bone loss was defined as a calcaneus BMD T-score of <-1. Blood cadmium and lead and plasma selenium levels were measured using inductively coupled plasma mass spectrometry. Levels of urinary arsenic species were determined using high-performance liquid chromatography-hydride generator-atomic absorption spectrometry. The total urinary arsenic level was defined as the sum of the levels of urinary arsenic species. The BMD T-scores decreased significantly with increasing blood lead levels. The BMD T-scores also showed a downward trend with increasing total urinary arsenic levels. The odds ratio (OR) and 95% confidence interval (CI) for bone loss in patients with blood lead levels >57.58 versus 35.74 μg/dL were 1.98 and 1.17-3.34. In addition, the greater the lead or arsenic exposure and alcohol intake was the higher the OR for bone loss with multivariate ORs of 2.57 (95% CI 1.45-4.56) and 2.96 (95% CI 1.67-5.22), respectively. To the best of our knowledge, this study is the first to demonstrate that high total urinary arsenic or blood lead levels and frequent or occasional alcohol consumption had a significant multiplicative interaction for increasing the OR for bone loss.

Maternal Dietary Selenium Intake during Pregnancy Is Associated with Higher Birth Weight and Lower Risk of Small for Gestational Age Births in the Norwegian Mother, Father and Child Cohort Study

Selenium is an essential trace element involved in the body’s redox reactions. Low selenium intake during pregnancy has been associated with low birth weight and an increased risk of children being born small for gestational age (SGA). Based on data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN), we studied the association of maternal selenium intake from diet and supplements during the first half of pregnancy (n = 71,728 women) and selenium status in mid-pregnancy (n = 2628 women) with birth weight and SGA status, according to population-based, ultrasound-based and customized growth standards. An increase of one standard deviation of maternal dietary selenium intake was associated with increased birth weight z-scores (ß = 0.027, 95% CI: 0.007, 0.041) and lower SGA risk (OR = 0.91, 95% CI 0.86, 0.97) after adjusting for confounders. Maternal organic and inorganic selenium intake from supplements as well as whole blood selenium concentration were not associated with birth weight or SGA. Our results suggest that a maternal diet rich in selenium during pregnancy may be beneficial for foetal growth. However, the effect estimates were small and further studies are needed to elucidate the potential impact of selenium on foetal growth.

Study of chromium, selenium and bromine concentrations in blood serum of patients with parenteral nutrition treatment using total reflection X-ray fluorescence analysis

Total reflection X-ray fluorescence analysis (TXRF) was used to determine chromium, selenium and bromine concentrations in blood serum samples of 50 patients with parenteral nutrition treatment. The concentrations were measured two times, namely in the first day (I measurement) of the treatment and the seventh day (II measurement) after the chromium and selenium supplementation. For comparison purposes also serum samples of 50 patients without nutritional disorders, admitted to a planned surgical procedure to remove the gall bladder (cholecystectomy), were analyzed and treated as the control group. Descriptive statistics of measured concentrations of Cr, Se and Br both for the studied and control groups was determined. In order to check the effectiveness of Cr and Se supplementation, the results of the first and seventh day measurements for studied group were statistically compared with each other, with literature reference values and with the results of the control group (two-group comparison). These comparisons indicate the effectiveness of selenium supplementation in the applied treatment procedure. In the case of Cr and Br concentrations no statistically significant differences were observed. We conclude that monitoring of the concentration of the important trace elements in human serum should be standard procedure in parenteral nutrition treatment. In this monitoring the TXRF technique can be successfully used.

Serum level of antioxidant vitamins and minerals in patients with vitiligo, a systematic review and meta-analysis

BACKGROUND

Antioxidant status is considered as important factor in the pathogenesis of vitiligo. However, there are controversial findings about serum status of antioxidants in vitiligo patients. The purpose of this study was to systematically review the evidences comparing the serum levels of antioxidant vitamins and minerals between vitiligo patients and controls, and performing meta-analysis of the results.

METHODS

A comprehensive search was performed for studies comparing the serum status of antioxidant vitamins and minerals using following databases since inception up to 30 April 2020; PubMed, EMBASE, Scopus, and Web of Science. Data extraction was done by two independent reviewers. The data was pooled for serum level of each antioxidant comparing between vitiligo and control groups.

RESULTS

Thirteen studies were included in this systematic review. The serum level of vitamin A, C, E, selenium, zinc and copper were compared between vitiligo patients and controls in these studies. Eleven studies including 570 vitiligo cases and 580 controls were included in the meta-analysis. Serum vitamin A and copper level in vitiligo patients were only evaluated in single studies and not included in meta-analysis. Based on fixed effect model, there were no statistical difference between two groups regarding serum vitamin C (OR = 1.17, 95 % CI, 0.74-1.84, P = 0.495), and vitamin E (OR = 0.61, 95 % CI, 0.30-1.25, P = 0.180). Higher serum zinc can decrease the risk of vitiligo based on sensitivity analysis of the results. (OR = 0.29, 95 % CI 0.15-0.54, P < 0.001). Higher serum selenium level significantly increased the risk of vitiligo (OR = 4.31, 95 % CI, 2.72-6.81, P < 0.001). Vitamin A was not significantly different in two reported groups (6.35 ± 1.53 vs 6.77 ± 1.46 μg/mL, P > 0.05). Copper was significantly higher in vitiligo patients compared to controls (129 ± 33 vs 99 ± 19 μg /100 mL, P = 0.002).

CONCLUSION

The current meta-analysis of data on serum level of most studied antioxidants (vitamin C, vitamin E, zinc and selenium) in patients suffering vitiligo showed that higher serum selenium (OR = 4.31) and lower zinc level (OR = 0.29) can increased the risk of vitiligo. Potential mechanism associated with preventive effects of zinc and the depigmentation effect of selenium should be more elucidated in further studies.

Selenium levels and skin diseases: systematic review and meta-analysis

BACKGROUND

Several studies have investigated the association between selenium levels and skin diseases, but reached inconsistent results.

OBJECTIVE

This systematic review and meta-analysis was conducted to evaluate the association between selenium levels and skin diseases.

METHODS

A systematic search was conducted in public databases to identify all relevant studies, and study-specific standard mean differences (SMD) and 95% confidence intervals (CI) were pooled to compare the selenium levels between different groups.

RESULTS

Twenty-seven studies were identified with a total of 1315 patient and 7181 healthy controls. Compared with controls, no significant difference in selenium was found in patients with vitiligo (SMD = 0.53, 95% CI: -0.40 to 1.45), alopecia areata (SMD = 0.47, 95% CI: -2.72 and 3.65), or eczema (SMD = 0.12, 95% CI: -0.24 to 0.48). A lower selenium level was found in patients with psoriasis (SMD = -0.62, 95% CI: -1.15 to -0.10), acne vulgaris (SMD = -1.02, 95% CI: -1.45 to -0.60), chloric acne (SMD = -2.35, 95% CI: -3.15 to -1.55), and atopic dermatitis (SMD = -2.62, 95% CI: -3.00 to -2.24). As for disease severity, severe patients had a higher selenium level than mild patients in psoriasis (SMD = 0.72, 95% CI: 0.07-1.38), but no difference was found in vitiligo (SMD = -0.26, 95% CI: -2.38 to 1.85) and alopecia areata (SMD = 0.46, 95% CI: -0.34 to 1.26).

CONCLUSION

Selenium levels were associated with several skin diseases and the disease severity, and high selenium levels tended to be a protective factor in certain skin diseases.

Essential trace elements in Norwegian obese patients before and 12 months after Roux-en-Y gastric bypass surgery: Copper, manganese, selenium and zinc

OBJECTIVES

The objective of the present study was to assess trace element status in morbidly obese subjects before and one year after Roux-en-Y gastric bypass (RYGB) in order to identify possible deficiencies.

METHODS

The study population included 46 patients in the age range 27-59 years, the majority (85 %) were women. The enrolled patients attended an eight week course on lifestyle changes before bariatric surgery. After RYGB they were recommended daily micronutrient supplements with a commonly used multivitamin-mineral tablet in addition to intramuscular vitamin B₁₂ injections (1 mg) every third month for 12 months. Whole blood concentrations of Cu, Mn, Se and Zn were determined using high resolution inductively coupled plasma mass spectrometry.

RESULTS

During the 12 months follow up after bariatric surgery, the patients had lost mean 32.3 kg and median whole blood concentrations of Cu (-16 %) were reduced, Mn (+14 %) and Zn (+6%) were increased, while the Se values were essentially unchanged. Compared with reference ranges, median postoperative concentrations of all essential trace elements were either below (Zn) or in the lower reference range (Cu, Mn, Se).

CONCLUSION

Essential trace elements were below or in the lower reference range twelve months after RYGB. Our results indicate a need for updated guidelines in Nordic countries for trace metal monitoring and supplements in patients after bariatric surgery, especially when gastric bypass surgery is used. Further studies are required to explore and prevent trace element deficiency related to obesity and bariatric surgery.

LncRNA MIAT regulated by selenium and T-2 toxin increases NF-κB-p65 activation, promoting the progress of Kashin-Beck Disease

LncRNA myocardial infarction associated transcript (MIAT) has been shown to be involved in osteoarthritis (OA), but its role in Kashin-Beck Disease (KBD) has rarely been reported. In this study, rats were administered with low selenium and/or T-2 toxin for 4 weeks to establish a KBD animal model. The serum selenium level, TNF-α and IL-1β contents, phosphorylated p65 (p-p65) and MIAT expression were increased in each intervention group. Next, we isolated the primary epiphyseal chondrocytes, and found that selenium treatment reversed the effects of T-2 toxin on chondrocyte injury, p-p65 and MIAT expression. In addition, MIAT overexpression or T-2 toxin treatment led to increased cell death, apoptosis, inflammation, NF-κB-p65 pathway activation and MIAT expression, which was rescued by selenium treatment or MIAT siRNA transfection. Our results suggested that lncRNA MIAT regulated by selenium and T-2 toxin increased the activation of NF-κB-p65, thus being involved in the progress of KBD.

Se Status Prediction by Food Intake as Compared to Circulating Biomarkers in a West Algerian Population

Algeria is the largest country in Africa, located close to the Mediterranean coastal area, where nutrients consumption varies widely. Local data on selenium composition of foods are not available. We postulated a close correlation between selenium status predictions from food consumption analysis with a quantitative analysis of circulating biomarkers of selenium status. Population characteristics were recorded from 158 participants and dietary selenium intake was calculated by 24-h recall. The average total plasma selenium was 92.4 ± 18.5 µg/L and the mean of selenium intake was 62.7 µg/day. The selenoprotein P concentration was 5.5 ± 2.0 mg/L and glutathione peroxidase 3 activity was 247.3 ± 41.5 U/L. A direct comparison of the dietary-derived selenium status to the circulating selenium biomarkers showed no significant interrelation. Based on absolute intakes of meat, potato and eggs, a model was deduced that outperforms the intake composition-based prediction from all food components significantly (DeLong’s test, p = 0.029), yielding an area under the curve of 82%. Selenium status prediction from food intake remains a challenge. Imprecision of survey method or information on nutrient composition makes extrapolating selenium intake from food data providing incorrect insights into the nutritional status of a given population, and laboratory analyses are needed for reliable information.

Micronutrient levels and their effects on the prognosis of visceral leishmaniasis treatment, a prospective cohort study

BACKGROUND

Micronutrients are minerals and vitamins and they are essential for normal physiological activities. The objectives of the study were to describe the progress and determinants of micronutrient levels and to assess the effects of micronutrients in the treatment outcome of kalazar.

METHODS

A prospective cohort study design was used. The data were collected using patient interviews, measuring anthropometric indicators, and collecting laboratory samples. The blood samples were collected at five different periods during the leishmaniasis treatments: before starting anti-leishmaniasis treatments, in the first week, in the second week, in the third week, and in the 4th week of anti-leishmaniasis treatments. Descriptive statistics were used to describe the profile of patients and to compare the treatment success rate. The generalized estimating equation was used to identify the determinants of serum micronutrients.

RESULTS

The mean age of the patients were 32.88 years [SD (standard deviation) ±15.95]. Male constitute 62.3% of the patients and problematic alcohol use was present in 11.5% of the patients. The serum zinc level of visceral leishmaniasis patients was affected by alcohol (B - 2.7 [95% CI: - 4.01 - -1.5]), DDS (B 9.75 [95% CI: 7.71-11.79]), family size (B -1.63 [95% CI: - 2.68 - -0.58]), HIV (B -2.95 [95% CI: - 4.97 - -0.92]), and sex (B - 1.28 [95% CI: - 2.5 - -0.07]). The serum iron level of visceral leishmaniasis patients was affected by alcohol (B 7.6 [95% CI: 5.86-9.35]), family size (B -5.14 [95% CI: - 7.01 - -3.28]), malaria (B -12.69 [95% CI: - 14.53 - -10.87]), Hookworm (- 4.48 [- 6.82 - -2.14]), chronic diseases (B -7.44 [95% CI: - 9.75 - -5.13]), and HIV (B -5.51 [95% CI: - 8.23 - -2.78]). The serum selenium level of visceral leishmaniasis patient was affected by HIV (B -18.1 [95% CI: - 20.63 - -15.58]) and family size (B -11.36 [95% CI: - 13.02 - -9.7]). The iodine level of visceral leishmaniasis patient was affected by HIV (B -38.02 [95% CI: - 41.98 - -34.06]), DDS (B 25 .84 [95% CI: 22.57-29.1]), smoking (B -12.34 [95% CI: - 15.98 - -8.7]), chronic illness (B -5.14 [95% CI: - 7.82 - -2.46]), and regular physical exercise (B 5.82 [95% CI: 0.39-11.26]). The serum vitamin D level of visceral leishmaniasis patient was affected by HIV (B -9.43 [95% CI: - 10.92 - -7.94]), DDS (B 16.24 [95% CI: 14.89-17.58]), malaria (B -0.61 [95% CI: - 3.37 - -3.37]), and family size (B -1.15 [95% CI: - 2.03 - -0.28]). The serum vitamin A level of visceral leishmaniasis patient was affected by residence (B 0.81 [95% CI: 0.08-1.54]), BMI (B 1.52 [95% CI: 0.42-2.6]), DDS (B 1.62 [95% CI: 0.36-2.88]), family size (B -5.03 [95% CI: - 5.83 - -4.22]), HIV (B -2.89 [95% CI: - 4.44 - -1.34]),MUAC (B 0.86 [95% CI: 0.52-1.21]), and age (B 0.09 [95% CI: 0.07-0.12]).

CONCLUSION

The micronutrient levels of visceral leishmaniasis patients were significantly lower. The anti-leishmaniasis treatment did not increase the serum micronutrient level of the patients.

Soil Selenium Concentration and Residents Daily Dietary Intake in a Selenosis Area: A Preliminary Study in Yutangba Village, Enshi City, China

In 1963, selenosis occurred in Yutangba Village, Enshi City, China. Subsequently, local residents migrated to a new area of Yutangba to avoid high selenium (Se) exposure. In this study, 19 soil samples, 43 food samples, 60 hair samples and 58 plasma samples from local residents were randomly collected in New Yutangba Village. The mean total Se concentrations in cultivated soil samples were 1753.6 ± 742.8 µg/kg (n = 14). The estimated daily Se intake in New Yutangba Village decreased to 63.2 ± 39.8 µg/day, slightly higher than the recommended dietary Se intake for adults in China (60 µg/day). The mean Se concentrations in hair and plasma samples were 549.7 ± 165.2 µg/kg (n = 60) and 98.4 ± 32.1 µg/L (n = 58), respectively. The result indicated that appropriate activities, such as relocation, consuming a mixture of local foods and market foods containing low Se concentration, could effectively reduce the risk of high Se exposure.

Current State of Evidence: Influence of Nutritional and Nutrigenetic Factors on Immunity in the COVID-19 Pandemic Framework

The pandemic caused by the new coronavirus has caused shock waves in many countries, producing a global health crisis worldwide. Lack of knowledge of the biological mechanisms of viruses, plus the absence of effective treatments against the disease (COVID-19) and/or vaccines have pulled factors that can compromise the proper functioning of the immune system to fight against infectious diseases into the spotlight. The optimal status of specific nutrients is considered crucial to keeping immune components within their normal activity, helping to avoid and overcome infections. Specifically, the European Food Safety Authority (EFSA) evaluated and deems six vitamins (D, A, C, Folate, B6, B12) and four minerals (zinc, iron, copper and selenium) to be essential for the normal functioning of the immune system, due to the scientific evidence collected so far. In this report, an update on the evidence of the contribution of nutritional factors as immune-enhancing aspects, factors that could reduce their bioavailability, and the role of the optimal status of these nutrients within the COVID-19 pandemic context was carried out. First, a non-systematic review of the current state of knowledge regarding the impact of an optimal nutritional status of these nutrients on the proper functioning of the immune system as well as their potential role in COVID-19 prevention/treatment was carried out by searching for available scientific evidence in PubMed and LitCovid databases. Second, a compilation from published sources and an analysis of nutritional data from 10 European countries was performed, and the relationship between country nutritional status and epidemiological COVID-19 data (available in the Worldometers database) was evaluated following an ecological study design. Furthermore, the potential effect of genetics was considered through the selection of genetic variants previously identified in Genome-Wide Association studies (GWAs) as influencing the nutritional status of these 10 considered nutrients. Therefore, access to genetic information in accessible databases (1000genomes, by Ensembl) of individuals from European populations enabled an approximation that countries might present a greater risk of suboptimal status of the nutrients studied. Results from the review approach show the importance of maintaining a correct nutritional status of these 10 nutrients analyzed for the health of the immune system, highlighting the importance of Vitamin D and iron in the context of COVID-19. Besides, the ecological study demonstrates that intake levels of relevant micronutrients-especially Vitamins D, C, B12, and iron-are inversely associated with higher COVID-19 incidence and/or mortality, particularly in populations genetically predisposed to show lower micronutrient status. In conclusion, nutrigenetic data provided by joint assessment of 10 essential nutrients for the functioning of the immune system and of the genetic factors that can limit their bioavailability can be a fundamental tool to help strengthen the immune system of individuals and prepare populations to fight against infectious diseases such as COVID-19.

Serum selenium levels of pre-eclamptic and normal pregnant women in Nigeria: A comparative study

INTRODUCTION

Trace element selenium, an antioxidant, and peroxynitrite scavenger when incorporated into selenoproteins and enzymes reduce oxidative stress which is implicated in the aetiopathogenesis of pre-eclampsia. A paucity of information exists on the serum selenium levels among pre-eclamptic pregnant women in Nigeria, hence the need for this study.

OBJECTIVE

To compare mean serum selenium levels and prevalence of selenium deficiency in preeclamptic pregnant women and their normotensive pregnant controls.

MATERIALS AND METHODS

A comparative case-control study was carried out at the Department of Obstetrics and Gynaecology, Federal Medical Centre, Owerri, Imo state. Fifty-eight preeclamptic and equal normotensive pregnant controls were matched for age groups, gestational age groups, parity groups, and socio-economic status had their serum samples analyzed for selenium level using atomic absorption spectrophotometer (ASS). Data analysis was done using the statistical package for social sciences (SPSS) version 20.0. P-value of < 0.05 was considered to be statistically significant.

RESULT

Mean serum selenium levels of the preeclamptic women(0.67±0.27μmol/l) was significantly (p<0.001) lower than that of the normotensive controls(1.20±0.46μmol/l). Selenium deficiency occurred significantly more in preeclamptic women (33(56.9%) than normotensive women (10(17.2%). Pearson's coefficient analysis showed negative correlation between serum selenium level with severity of systolic blood pressure (Correlation Coefficient (r) = -0.593), diastolic blood pressure(r = -0.519) and severity of preeclampsia(r = -0.598).

CONCLUSION

Serum selenium levels of pre-eclamptic women were significantly lower compared to that of normotensive pregnant controls and selenium deficiency occurred significantly more among the preeclamptic pregnant women compared to the normotensive controls. Selenium level dynamics in pregnancy possibly could play a role in the incidence of pre-eclampsia among pregnant women.

Comparison of Bioavailability, Pharmacokinetics, and Biotransformation of Selenium-Enriched Yeast and Sodium Selenite in Rats Using Plasma Selenium and Selenomethionine

For the first time, bioavailability, pharmacokinetics, and biotransformation of selenium-enriched yeast (SeY) and sodium selenite (Na₂SeO₃) in rats were systemically compared by analyzing free selenomethionine (SeMet), total SeMet, and selenium (Se). After SeY and Na₂SeO₃ were orally administered to rats at a dose of 100 μg Se/kg, plasma free SeMet, total SeMet, and Se at various time points were determined by ultra-performance liquid chromatography-tandem mass spectrometry. Based on Se and total SeMet, the relative bioavailability values of SeY compared with Na₂SeO₃ were 144% and 272%, respectively. For the rats treated with SeY, 0.73-2.68% of total Se was biotransformed to free SeMet, 14.3-20.4% to SeMet-proteins and albumin-bound SeMet, and 75.9-82.3% to selenoproteins in plasma. SeY had higher bioavailability than Na₂SeO₃ based on Se and total SeMet levels. Plasma SeMet was the optimal biomarker of SeY status in vivo.

Serum antioxidant micronutrient levels in pre-eclamptic pregnant women in Enugu, south-East Nigeria: a comparative cross-sectional analytical study

BACKGROUND

Pre-eclampsia is a common obstetric complication of pregnancy in Nigeria, and oxidative stress has been implicated in its aetiopathogenesis. Despite this fact, there is a paucity of information regarding the serum antioxidant micronutrient status of pre-eclamptic Nigerian women. The objective of the was to determine the mean serum levels of some antioxidant trace elements (copper, zinc, selenium, magnesium, manganese) in pre-eclamptic pregnant women and compare with that of healthy pregnant women in Enugu, South-Eastern, Nigeria.

METHODS

A cross-sectional analytical study was carried out at the Obstetrics and Gynaecology department of the University of Nigeria, Teaching Hospital Ituku-Ozalla, Enugu. Using atomic absorption spectrophotometry, the sera of 81 pregnant pre-eclamptic and 81 matched healthy pregnant controls were analyzed for the antioxidant micronutrients. Both descriptive and inferential analysis was performed using the statistical package for social sciences (SPSS) version 21.0 and a P value of < 0.05 was considered to be statistically significant.

RESULTS

The mean serum levels of copper, selenium, and magnesium were found to be significantly lower in the pre-eclamptic pregnant group when compared to the healthy pregnant controls (p < 0.05). The mean serum levels of zinc and manganese did not differ between the two groups (p > 0.05). All the mean serum levels of micro-nutrients studied did not vary by category of pre-eclampsia (with or without severity findings) except manganese which was significantly lower in pre-eclamptic women without severity findings when compared to those with severity findings (p = 0.043).

CONCLUSIONS

The serum levels of copper, selenium, and magnesium were significantly lower among pre-eclamptics when compared to their normal healthy controls. Low levels of selenium, copper, and magnesium may have contributed to the incidence of pre-eclampsia in our environment.

Selenium and Copper as Biomarkers for Pulmonary Arterial Hypertension in Systemic Sclerosis

Circulating selenoprotein P (SELENOP) constitutes an established biomarker of Se status. SELENOP concentrations are reduced in inflammation and severe disease. Recently, elevated SELENOP levels have been suggested as diagnostic marker and therapeutic target in pulmonary arterial hypertension (PAH). We decided to re-evaluate this hypothesis. A group of healthy controls (n = 30) was compared with patients suffering from systemic sclerosis (SSc, n = 66), one third with SSc-related PAH. Serum was analysed for trace elements and protein biomarkers, namely SELENOP, glutathione peroxidase 3 (GPx3) and ceruloplasmin (CP). Compared to controls, patients with SSc-related PAH displayed reduced serum Se (91 ± 2 vs. 68 ± 2 µg/L) and SELENOP concentrations (3.7 ± 0.8 vs. 2.7 ± 0.9 mg/L), along with lower GPx3 activity (278 ± 40 vs. 231 ± 54 U/L). All three biomarkers of Se status were particularly low in patients with skin involvement. Serum Cu was not different between the groups, but patients with SSc-related PAH showed elevated ratios of Cu/Se and CP/SELENOP as compared to controls. Our data indicate that patients with SSc-related PAH are characterized by reduced Se status in combination with elevated CP, in line with other inflammatory diseases. Further analyses are needed to verify the diagnostic value of these TE-related biomarkers in PAH.

The Role of Selenium Mineral Trace Element in Exercise: Antioxidant Defense System, Muscle Performance, Hormone Response, and Athletic Performance. A Systematic Review

Exercise overproduces oxygen reactive species (ROS) and eventually exceeds the body’s antioxidant capacity to neutralize them. The ROS produce damaging effects on the cell membrane and contribute to skeletal muscle damage. Selenium (Se), a natural mineral trace element, is an essential component of selenoproteins that plays an important role in antioxidant defense. The activity of the enzyme glutathione peroxidase (GPx), a highly-efficient antioxidant enzyme, is closely dependent on the presence of Se. These properties of Se may be potentially applicable to improve athletic performance and training recovery. We systematically searched for published studies to evaluate the effectiveness of Se supplementation on antioxidant defense system, muscle performance, hormone response, and athletic performance among physically active individuals. We used the Preferred Reporting Elements for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and searched in SCOPUS, Web of Science (WOS), and PubMed databases to identify published studies until March 2020. The systematic review incorporated original studies with randomized controlled crossover or parallel design in which intake of Se administered once a day was compared with the same placebo conditions. No exclusions were applied for the type of physical exercise performed, the sex, nor the age of the participants. Among 150 articles identified in the search, 6 met the criteria and were included in the systematic review. The methodological quality of the studies was evaluated using the McMaster Critical Review Form. Oral Se supplementation with 180 µg/day or 240 µg/day (selenomethionine) and 200 µg/day (Sodium Selenite), significantly decreased lipid hydroperoxide levels and increased GPx in plasma, erythrocyte, and muscle. No significant effects were observed on athletic performance, testosterone hormone levels, creatine kinase activity, and exercise training-induced adaptations on oxidative enzyme activities or on muscle fiber type myosin heavy chain expression. In addition, Se supplementation showed to have a dampening effect on the mitochondria changes in chronic and acute exercise. In summary, the use of Se supplementation has no benefits on aerobic or anaerobic athletic performance but it may prevent Se deficiencies among athletes with high-intensity and high-volume training. Optimal Se plasma levels may be important to minimize chronic exercise-induced oxidative effects and modulate the exercise effect on mitochondrial changes.

Effect of Slow-Release Pellets of Selenium and Iodine on Performance and Some Blood Metabolites of Pregnant Moghani Ewes and Their Lambs

The need for minerals during pregnancy in mammals increases by progress of gestation due to embryo development. Therefore, the supply of trace minerals for pregnant ewes in late pregnancy may be of vital importance. The present study was carried out to evaluate the effect of selenium and iodine release slowly on the performance and some blood parameters of pregnant ewes and their lambs. Experiments were performed on 40 pregnant ewes from 3 to 4 years old in the last month of pregnancy with a weighing average of 52 ± 5 kg and a factorial experiment (2 × 2) in a completely randomized design with 4 treatments and 10 replicates used for 120 days (30 days before and 90 days after parturition of ewes). Experimental treatments were containing the following: (1) control, (2) ewe receiving bolus containing iodine, (3) ewe receiving bolus containing iodine and selenium, and (4) ewe receiving bolus containing selenium. One month before the expected birth date, the pellets will be fed to each of the livestock by bolus gun. During the test period, ewes will not receive any other mineral supplements and will be kept in a group in a herd. Ewes were blood sampled at 10 days prepartum and 30 and 60 days postpartum. The results showed that body weight on birth and weaning of lambs and average daily gain of lambs were highest in bloused animals that were related to the slow-release selenium tablet lambs (P < 0.05). Lambs born to mothers receiving 0.3 mg day^-1 of selenium per day had a keratin phosphokinase concentration of T₄ concentration and T₄ to T₃ lower than that of zero selenium (P < 0.05). Daily gain, glutathione peroxidase activity, and T₄ concentration at iodine 0.4 mg day^-1 were significantly higher than iodine level (P < 0.05). The adding of slow- release pellets of iodine and selenium improved the immune system.

Effects of Dietary Supplementation with Selenium and Vitamin E on Growth Performance, Nutrient Apparent Digestibility and Blood Parameters in Female Sika Deer (Cervus nippon)

To evaluate the effects of selenium (Se) and vitamin E (Vit E) on female sika deer. This study was conducted using a 3 × 2 + 1 factorial experiment. Depending on treatment design, the deer were fed with the basal diet supplemented with 0.2, 0.3, and 0.4 mg of selenium as well as 100 and 200 IU of vitamin E per kg of dry matter (DM). Accordingly, six groups named G1 to G6 are involved in this study. In addition, group G0 was available in the study, in which the deer were fed with only basal diet. The results show that the final body weight (BW), average daily gain (ADG), and apparent digestibility of crude protein, ether extract, and neutral detergent fiber of the deer in G1 to G6 increased as the selenium level increased from 0.2 to 0.3 mg per kg of DM (P < 0.05). Higher IgG content of the deer was observed with the intake of selenium and vitamin E (P < 0.05). The total content of protein of the deer in G3 was higher than that in G0 (P < 0.05), and the activity of glutathione peroxidase increased following the increase in the supplementation levels of selenium and vitamin E (P < 0.05). Furthermore, selenium had significant effects on the concentration of T4 and T3 (P < 0.05). The optimum levels of selenium and vitamin E for 1-year-old female sika deer were 0.3 mg and 100 IU per kg of dietary DM, respectively.

Association of CYP4F2 and CTRP9 polymorphisms and serum selenium levels with coronary artery disease

Aims to explore the interaction between serum selenium level and CYP4F2 and CTRP9 gene polymorphisms in the development of coronary artery disease (CAD).A total of 200 cases of CAD were selected from the Central Hospital of Enshi Tujia and Miao Autonomous Prefecture, Hubei, China, and 200 healthy subjects cases were served as controls. The polymorphism of CYP4F2 and CTRP9 gene was detected by Sanger sequencing, and the serum selenium level was measured by hydride generation atomic fluorescence spectrometry.The serum selenium level in the CAD group was significantly lower than that in the control group. The risk of CAD was decreased in the patients carrying the AA genotype in CYP4F2 rs3093135, while the frequency of the CC genotype of CTRP9 rs9553238 in CAD patients was higher than that in control subjects. Low serum selenium level and CTRP9 rs9553238 CC genotype play a positive role in the occurrence of CAD.The serum selenium level is negatively correlated with CAD. The polymorphism of the CYP4F2 rs3093135 and CTRP9 rs9553238 was significantly related to the susceptibility of CAD, and there is a synergistic effect between the serum selenium level and the CTRP9 rs9553238 CC genotype, which significantly increases the risk of CAD.

Mercury Exposure Assessment in Mother-Infant Pairs from Continental and Coastal Croatia

The main source of mercury (Hg) exposure in the general population is fish. Another possible source is dental amalgam. Here, we compare the levels of Hg and selenium (Se) in samples of maternal and fetal origin collected shortly after childbirth of healthy postpartum women in the coastal (n = 96) and continental (n = 185) areas of Croatia related to maternal seafood/fish consumption. We also evaluated Hg concentrations and maternal serum metallothionein (MT2) concentrations in relation to the number of dental amalgam fillings, and MT2A-5A/G (rs28366003) polymorphism. The levels of Hg and Se in maternal hair and blood/serum, placenta and cord blood/serum increased in relation to increasing fish consumption with the highest values in subjects from the coast. The concentrations of each element and between elements correlated across the matrices. Increasing amalgam number correlated linearly with increased Hg levels in maternal and cord serum and was not associated with serum MT2. No association of MT2A-5A/G polymorphism and Hg or Se levels were found. The results confirmed higher fish consumption in coastal vs. continental Croatia and increases of both Hg and Se related to fish consumption in all analyzed samples. Increased blood Hg reflected the predominant MeHg share from seafood, while increased serum Hg matched exposure from dental amalgams.

Selenium Status after Roux-en-Y Gastric Bypass: Interventions and Recommendations

BACKGROUND

Selenium is an essential element that plays a vital role in maintaining human health and its deficiency can lead to cardiovascular and hypothyroidism complications. In this context, the main concern is about morbidly obese patients who undergo a Roux-en-Y Gastric Bypass (RYGB). Although RYGB leads to 60-70% excess weight loss, micronutrient deficiencies are common after this procedure and can be problematic if not promptly detected. This review will therefore examine the evidence regarding selenium deficiency in RYGB patients, as well its nutritional treatment methods.

METHODS

There were a total of 6 studies regarding RYGB and selenium deficiency, which were retrieved from PUBMED and SCOPUS electronic databases, ranging from 2006 to 2017.

CONCLUSION

Selenium deficiency was observed before and after RYGB. Lifelong supplementation and regular patient monitoring after surgery are recommended.