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Serum selenium and serum lipids in US adults: National Health and Nutrition Examination Survey (NHANES) 2003–2004
Abstract
High selenium has been recently associated with several cardiovascular and metabolic risk factors including diabetes, blood pressure and lipid levels. We evaluated the association of serum selenium with fasting serum lipid levels in the National Health and Nutrition Examination Survey (NHANES) 2003-2004, the most recently available representative sample of the US population that measured selenium levels.
Cross-sectional analysis of 1159 adults>or=40 years old from NHANES 2003-2004. Serum selenium was measured by inductively coupled plasma-dynamic reaction cell-mass spectrometry. Fasting serum total cholesterol, triglycerides, and HDL cholesterol were measured enzymatically and LDL cholesterol was calculated.
Mean serum selenium was 136.7 microg/L. The multivariable adjusted average differences (95% confidence interval) comparing the highest (>or=147 microg/L) to the lowest (<124 microg/L) selenium quartiles were 18.9 (9.9, 28.0) mg/dL for total cholesterol, 12.7 (3.3, 22.2) mg/dL for LDL cholesterol, 3.9 (0.4, 7.5)mg/dL for HDL cholesterol, and 11.5 (-7.6, 30.7) mg/dL for triglycerides. In spline regression models, total and LDL cholesterol levels increased progressively with increasing selenium concentrations. HDL cholesterol increased with selenium but reached a plateau above 120 microg/L of serum selenium (20th percentile). The triglyceride-selenium relationship was U-shaped.
In US adults, high serum selenium concentrations were associated with increased serum concentrations of total and LDL cholesterol. Selenium was associated with increasing HDL cholesterol only at low selenium levels. Given increasing trends in dietary selenium intake and supplementation, the causal mechanisms underlying these associations need to be fully characterized.
... In the present study, we did not find a significant effect of treatments on total cholesterol, but it was observed that HDL cholesterol levels are positively associated with the antioxidants group, as previously described by others' works [40][41][42][43]. In longitudinal analyses with elderly volunteers, the increasing plasma selenium concentrations were associated with decreasing total cholesterol levels and increasing HDL cholesterol levels [44]. ...
... Similarly, a China cross-sectional study with 1859 participants (aged 65 or older) observed that higher selenium levels were significantly associated with a lower risk of low-HDL [42]. In the USA, selenium in adults also was associated with increasing HDL [41]. ...
This study aimed to investigate the effects of meat biofortified with antioxidants and canola oil on the health of older adults through blood parameters. Eighty institutionalized older persons were divided into four groups who received the following treatments: C-control meat with 46 µg/kg of meat with selenium, 3.80 g/kg of meat with vitamin E and 0.78 g/100 g of meat with conjugated linoleic acid (CLA); A-antioxidant meat with 422 µg/kg of meat with selenium, 7.65 g/kg of meat with vitamin E and 0.85 g/100 g of meat with CLA; O-oil meat with 57 µg/kg of meat with selenium, 3.98 g/kg of meat with vitamin E and 1.27 g/100 g of meat with CLA; OA-oil and antioxidant meat with 367 µg/kg of meat with selenium, 7.78 g/kg of meat with vitamin E and 1.08 g/100 g of meat with CLA. Blood samples were collected at 0, 45 and 90 days after the start of meat intake. Older adults who consumed ANT (A and AO) meat had higher concentrations of selenium (p = 0.039), vitamin E and HDL (higher concentrations of high-density lipoprotein, p = 0.048) in their blood. This study demonstrates that the consumption of Se- and vitamin E-biofortified meat increases the concentration of these metabolites in blood from older adults.
... The main route of selenium exposure in the general population is diet [95][96][97], with major dietary sources including breads, grains, cereals, Brazil nuts, red meat, poultry, fish, and eggs [62,[98][99][100]. Although protective effects were initially hypothesized for selenium intake and cardiometabolic diseases [74], recent findings from both observational studies and randomized controlled trials have indicated that high concentrations of selenium, measured in serum/plasma [21,[101][102][103][104][105] or estimated dietary intake [106,107], may lead to excess risk of cardiometabolic diseases [21,[101][102][103][104][105][106][107], including hyperlipidemia [108], as has been reported for other outcomes such as cancer, type 2 diabetes, and neurodegenerative disorders [109,110]. While the potential mechanisms linking high selenium intake to dysregulated lipid metabolism are not clear, insulin sensitivity [111], inflammation [112], oxidative stress [113,114], liver damage [115,116], and increased LDL-receptor mRNA expression and activity [117,118] have been hypothesized as possible mediators. ...
... The main route of selenium exposure in the general population is diet [95][96][97], with major dietary sources including breads, grains, cereals, Brazil nuts, red meat, poultry, fish, and eggs [62,[98][99][100]. Although protective effects were initially hypothesized for selenium intake and cardiometabolic diseases [74], recent findings from both observational studies and randomized controlled trials have indicated that high concentrations of selenium, measured in serum/plasma [21,[101][102][103][104][105] or estimated dietary intake [106,107], may lead to excess risk of cardiometabolic diseases [21,[101][102][103][104][105][106][107], including hyperlipidemia [108], as has been reported for other outcomes such as cancer, type 2 diabetes, and neurodegenerative disorders [109,110]. While the potential mechanisms linking high selenium intake to dysregulated lipid metabolism are not clear, insulin sensitivity [111], inflammation [112], oxidative stress [113,114], liver damage [115,116], and increased LDL-receptor mRNA expression and activity [117,118] have been hypothesized as possible mediators. ...
Background
Growing evidence suggests that cardiovascular disease develops over the lifetime, often beginning in childhood. Metal exposures have been associated with cardiovascular disease and important risk factors, including dyslipidemia, but prior studies have largely focused on adult populations and single metal exposures.
Objective
To investigate the individual and joint impacts of multiple metal exposures on lipid levels during childhood.
Methods
This cross-sectional study included 291 4-year-old children from the Rhea Cohort Study in Heraklion, Greece. Seven metals (manganese, cobalt, selenium, molybdenum, cadmium, mercury, and lead) were measured in whole blood using inductively coupled plasma mass spectrometry. Serum lipid levels included total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol. To determine the joint and individual impacts of child metal exposures (log2-transformed) on lipid levels, Bayesian kernel machine regression (BKMR) was employed as the primary multi-pollutant approach. Potential effect modification by child sex and childhood environmental tobacco smoke exposure was also evaluated.
Results
BKMR identified a positive association between the metal mixture and both total and LDL cholesterol. Of the seven metals examined, selenium (median 90.6 [IQR = 83.6, 96.5] µg/L) was assigned the highest posterior inclusion probability for both total and LDL cholesterol. A difference in LDL cholesterol of 8.22 mg/dL (95% CI = 1.85, 14.59) was observed when blood selenium was set to its 75th versus 25th percentile, holding all other metals at their median values. In stratified analyses, the positive association between selenium and LDL cholesterol was only observed among boys or among children exposed to environmental tobacco smoke during childhood.
Impact statement
Growing evidence indicates that cardiovascular events in adulthood are the consequence of the lifelong atherosclerotic process that begins in childhood. Therefore, public health interventions targeting childhood cardiovascular risk factors may have a particularly profound impact on reducing the burden of cardiovascular disease. Although growing evidence supports that both essential and nonessential metals contribute to cardiovascular disease and risk factors, such as dyslipidemia, prior studies have mainly focused on single metal exposures in adult populations. To address this research gap, the current study investigated the joint impacts of multiple metal exposures on lipid concentrations in early childhood.
... Regarding the efect on blood lipids, the results of the current study are divergent. Several studies have found that serum selenium is related to the increase of TC (total cholesterol) level [34][35][36][37] and TG (triglycerides) level [35][36][37][38]. In addition, some studies found that serum selenium was associated with the decrease of TC and TG levels [39], but there was also a report that there was no statistical correlation between selenium and TG [34]. ...
... Several studies have found that serum selenium is related to the increase of TC (total cholesterol) level [34][35][36][37] and TG (triglycerides) level [35][36][37][38]. In addition, some studies found that serum selenium was associated with the decrease of TC and TG levels [39], but there was also a report that there was no statistical correlation between selenium and TG [34]. Other studies have shown that the relationship between selenium and blood lipids is dose-dependent, and high normal levels of selenium may increase the risk of diabetes [40]. ...
Objective. The main objective of this study is to evaluate the clinical efficacy of antithyroid drugs combined with antioxidant supplementation represented by selenium in the treatment of Graves’ disease. Methods. Relevant randomized controlled trials (RCTs) were searched in PubMed, MEDLINE, Embase, the Cochrane Library databases, and the Chinese Medical Association. The search was conducted from the time of library construction to December 20, 2022. Three writers gradually examined, evaluated, and graded the literature and then used RevMan 5.3 to analyze the data and develop conclusions. Results. A total of seven papers were screened according to the search requirements. The results showed that free triiodothyronine (FT3) (WMD = −2.29, 95% CI: −3.55 to −1.02, P = 0.0004 ), free thyroxine (FT4) (WMD = −0.62, 95% CI: −1.05 to −0.18, P = 0.0005 ), thyrotropin receptor antibody (TRAb) (WMD = −1.31, 95% CI: −1.63 to −0.99, P < 0.00001 ), and thyroid peroxidase antibody (TPOAb) (WMD = −9.8, 95% CI: −16.57 to −3.03, P = 0.005 ) in the observation group (selenium supplementation combined with antithyroid drugs) were significantly lower than those in the control group (antithyroid drugs combined with or without placebo). In addition, selenium supplementation can increase serum selenium (WMD = 33.29, 95% CI: 30.7 to 35.87, P < 0.00001 ), selenoprotein levels (WMD = 1.3, 95% CI: 0.8 to 1.8, P < 0.00001 ), and blood lipid levels (WMD = 32.3, 95% CI: 17.87 to 46.74, P < 0.0001 ). It cannot be excluded that the process of selenium supplementation treatment will affect the patient’s lipid levels. Conclusion. Selenium is a trace mineral that is crucial for human health. In patients with Graves’ disease, the use of antithyroid medications along with selenium supplementation can considerably enhance thyroid function. It has the potential to drastically lower TPOAb and TRAb levels as well as FT3 and FT4 levels, which is crucial for the treatment, recovery, and prognosis of hyperthyroid patients. Further research is required to determine whether the impact of antioxidant supplementation on blood lipids will restrict the use of this medication.
... This is clearly the case for type 2 diabetes based on randomized controlled trials [12] and observational studies [8], but it could also be true for hypertension and non-alcoholic fatty liver disease [10,35,36]. An association, either adverse or beneficial, between selenium status and lipid profile is considerably more controversial, due to conflicting findings from both experimental and non-experimental human studies [37][38][39][40][41][42]. In addition, there is still considerable uncertainty about what threshold of selenium exposure can trigger such adverse metabolic effects. ...
... The association of adverse lipid profile endpoints with urinary selenium is not entirely surprising, given the dose-response association between higher blood selenium concentrations and metabolic syndrome, higher triglycerides and LDL-cholesterol, as well as the lower HDL-cholesterol consistently found in the National Health and Nutrition Examination Surveys (NHANES) and other studies [39,52,54,[56][57][58]. Conversely, randomized controlled trials have shown little if any effect of selenium supplementation on the lipid profile [38,40]. ...
Selenium is both an essential nutrient and a highly toxic element, depending on its dose and chemical forms. We aimed to quantify urinary selenium excretion and dietary selenium intake in 137 healthy non-smoking blood donors living in the northern Italian province of Reggio Emilia. We assessed selenium status by determining urinary selenium levels (mean 26.77 µg/L), and by estimating dietary selenium intake (mean 84.09 µg/day) using a validated semi-quantitative food frequency questionnaire. Fasting blood levels of glucose, lipids and thyroid-stimulating hormone were measured using automatized laboratory procedures. Dietary and urinary selenium were correlated (beta coefficient (β) = 0.19). Despite this, the association of the two indicators with health endpoints tended to diverge. Using linear regression analysis adjusted for age, sex, body mass index, cotinine levels and alcohol intake, we observed a positive association between urinary selenium and blood triglyceride (β = 0.14), LDL-cholesterol (β = 0.07) and glucose levels (β = 0.08), and an inverse one with HDL-cholesterol (β = −0.12). Concerning dietary selenium, a slightly positive association could be found with glycemic levels only (β = 0.02), while a negative one emerged for other endpoints. The two selenium indicators showed conflicting and statistically highly imprecise associations with circulating TSH levels. Our findings suggest that higher selenium exposure is adversely associated with blood glucose levels and lipid profile. This is the case even at selenium exposures not exceeding tolerable upper intake levels according to current guidelines.
... Sweden, like Poland, is a country with low soil selenium [2,8,9,18]. In Poland, the mean serum selenium level among women is approximately 80-90 µg/L, compared to >130 µg/L in the United States [15,19]. We have reported a relationship between low serum selenium and the five year survival of patients with breast, lung and laryngeal cancer in Poland [20][21][22]. ...
... Data from the Nutritional Prevention of Cancer (NPC) trial suggest that the protective influence of selenium may be limited to individuals with reduced selenium levels [10]. In our study mean selenium level was 86.2 µg/L, compared to the United States where the mean serum selenium for women aged 40 or older is 134.7 µg/L [19]. ...
In a recent prospective study, we reported an association between a low serum selenium level and five-year survival among breast cancer patients. We now have updated the cohort to include 10-year survival rates. A blood sample was obtained from 538 women diagnosed with first primary invasive breast cancer between 2008 and 2015 in the region of Szczecin, Poland. Blood was collected before initiation of treatment. Serum selenium levels were quantified by mass spectroscopy. Each patient was assigned to one of four quartiles based on the distribution of serum selenium levels in the whole cohort. Patients were followed from diagnosis until death or last known alive (mean follow-up 7.9 years). The 10-year actuarial cumulative survival was 65.1% for women in the lowest quartile of serum selenium, compared to 86.7% for women in the highest quartile (p < 0.001 for difference). Further studies are needed to confirm the protective effect of selenium on breast cancer survival. If confirmed this may lead to an investigation of selenium supplementation on survival of breast cancer patients.
... However, several studies have also drawn controversial associations between dietary selenium intake and T2D. 40,41 Dias et al 42 reported that dietary selenium intake was not associated with the prevalence of T2D, despite the high intake of selenium in the participants. Another study, focused on north Chinese adults, suggested that there exists a positive correlation between dietary selenium intake and T2D. ...
Background
Clinically, metabolic syndrome (MetS) is associated with the formation and relapse of kidney stones diseases (KSD). In the general population, dietary selenium can reduce renal damage by reducing oxidative stress and other physiological pathways. Less is known, however, about the association between dietary selenium and KSD in patients with MetS.
Objective
The present study's purpose is to evaluate the association between dietary selenium intake and the odds of KSD in MetS populations.
Methods
Data of MetS patients aged ≥20 years were extracted from the National Health and Nutrition Examination Survey (NHANES) database (2007–2018). The information of dietary selenium intake was obtained by 24-hour dietary recall interview. Weighted univariable and multivariate logistic regression analyses were used to evaluate the association of selenium intake with KSD in MetS patients and described as odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analysis was performed to further discuss this association based on age, gender, and MetS component.
Results
In total, 6,073 patients were included, with 766 (12.61%) KSD cases. After adjusting for covariates, high dietary selenium intake was related to lower odds of KSD in MetS patients (OR = 0.70, 95% CI = 0.50–0.97), especially in females (OR = 0.61, 95% CI = 0.39–0.96), those aged <65 years (OR = 0.53, 95% CI = 0.35–0.80), without a history of hypertriglyceridemia (OR = 0.61, 95% CI = 0.40–0.93) and with a history of hypertension (OR = 0.57, 95% CI = 0.38–0.84), diabetes (OR = 0.68, 95% CI = 0.46–0.99) or central obesity (OR = 0.67, 95% CI = 0.48–0.95).
Conclusion
From this cross-sectional study, we observed that, among patients with MetS, high dietary selenium intake is associated with lower odds of KSD, implying a potential nutritional strategy for preventing KSD in this population.
... The NHANES 1988-1994 reported that median Se intakes were 106 µg/day from foods and 108 µg/day from foods and supplements, respectively (Institute of Medicine Panel, 2000). According to the NHANES 2003NHANES -2004, the mean serum Se concentrations in the US adults aged 40 years and above were 136.7 µg/L (Laclaustra et al., 2010). The average Se intakes in Americans aged 2 years and older were 108.5 µg/day from foods and 120.8 µg/day from both foods and supplements in the NHANES 2009. ...
Diets are the major sources of selenium (Se) and biomonitoring Se is used for the assessment of Se status. The present study explored the association between Se intake and blood Se concentration from the National Health and Nutrition Examination Survey 2011–2018 data for optimizing Se reference intakes among American adults and interpreted the data in the context of exposure guidance values. Weighted linear regression models were conducted to evaluate the association between Se intake and blood Se concentration. Restricted cubic spline models were employed to explore the dose–response association between total Se intake and blood Se concentration. Blood Se concentrations were compared to biomonitoring equivalents established for exposure guidance values. For gender, race, educational status, poverty income ratio, body mass index, smoking status, dietary Se intake, and total Se intake, significant differences were observed among quartiles of blood Se concentration. There was no significant difference for age and alcohol use. There was a positive association between dietary Se intake and blood Se concentration although the association was not statistically significant following the adjustments for covariates. When the associations between total Se intake and blood Se concentration were assessed, no statistically significant relationship was found. The restricted cubic spline supported a significant nonlinear association between total Se intake and blood Se concentration with/without the adjustments of covariates. The present work displayed a baseline for Se exposure among American adults. Considering the sex difference in dietary Se and blood Se concentration, it is necessary to establish gender‐based Se reference intakes.
... Studies investigating the link between Se status and lipid profiles have yielded inconsistent results. Some research has shown a positive correlation, where higher Se levels are associated with increased lipid levels [29], while other studies have found no significant relationship between Se and lipid profiles. For instance, Rashidi and colleagues [13] found that Se supplementation did not alter lipid profiles in women with PCOS. ...
Growing evidence indicates a potential link between polycystic ovary syndrome (PCOS) and selenium (Se) levels. This study aims to assess Se concentrations in Saudi women with and without PCOS and to explore the relationships between Se levels, insulin resistance (IR), adiponectin, and lipid markers. We randomly recruited 197 women aged 18 to 40, both with and without PCOS, for this age-matched case–control study. The PCOS participants were categorized into three groups based on their Se levels. All participants underwent interviews, and their anthropometric measurements and blood samples were collected for further analysis of biochemical variables. There was a notable difference between the two groups studied across all biochemical variables. Specifically, fasting blood glucose, insulin, the homeostasis model assessment (HOMA-IR) index, total cholesterol, low-density lipoprotein cholesterol, and triglycerides were significantly higher in the PCOS group compared to the control group (p < 0.01). Conversely, Se, high-density lipoprotein cholesterol, and adiponectin levels were significantly lower in women with PCOS than in their age-matched controls (p < 0.01). HOMA-IR was identified as the sole independent predictor of serum Se levels, explaining 17.2% of the variability in its circulating levels (β = − 0.57; 95% CI: − 0.96 to − 0.18, p = 0.004). The findings reveal that women with PCOS have lower serum Se levels compared to the controls. Furthermore, the results confirm a correlation between Se levels and insulin resistance.
... The correct supply of Se is one that ensures optimal activity of selenoprotein P, which is a Se transporter from the liver to tissues [65]. It has been shown that both deficiency and excess may have an adverse effect on the functioning of the body, thus increasing the risk of hypertension, thyroid dysfunction, limitations of the immune system and malignant tumors [66]. Due to the diverse occurrence of Se in particular regions of the world, Se supply standards differ on individual continents and even in individual countries. ...
Selenium was recognized as a non-toxic element in the second half of the 20th century. Since then, the positive impact of selenium on the functioning of the human body has been noticed. It has been shown that low levels of selenium in the body are significantly associated with a higher risk of developing cancer. Selenium acts as an antioxidant and inhibits the proliferation of cancer cells. It has been shown that selenium supplementation may contribute to reducing the risk of DNA mutations and carcinogenesis. Nanomedicine has become very helpful in both the diagnosis and treatment of cancer. Due to its anticancer properties, selenium is used in nanotechnology as selenium nanoparticles.
... Kohler et al. (26) conducted a cross-sectional analysis involving 1,727 participants from a randomized clinical trial on selenium supplementation for colorectal adenoma chemoprevention, finding that higher plasma selenium levels were significantly linked to T2D prevalence, which supports our findings. Two studies (27,28) utilizing NHANES data to explore the association between selenium and T2D in American participants, covering over 9,000 individuals, found that higher selenium concentrations were associated with increased incidence of T2D, with ORs of 1.57 (95% CI: 1.16, 2.13) and 7.64 (95% CI: 3.34, 17.46), respectively. Stranges et al. (29) reported from the Olivetti Heart Study in Italy that participants in the highest tertile of baseline selenium levels had a higher proportion of diabetes cases compared to those in the lowest tertile. ...
Background
Type 2 diabetes (T2D) is a growing global health concern. While micronutrients are crucial for physiological functions and metabolic balance, their precise links to T2D are not fully understood.
Methods
We investigated the causal relationships between 15 key micronutrients and T2D risk using both univariate and multivariate Mendelian randomization (MR) methods. Our analysis leveraged data from a large prospective cohort genome-wide association study (GWAS) on these micronutrients and T2D. We employed MR techniques such as inverse variance weighting (IVW), MR Egger, weighted median, and simple models. Multivariate analysis adjusted for diabetes-related factors like body mass index (BMI) and hypertension to assess the independent effects of micronutrients, particularly selenium, on T2D risk.
Results
Selenium intake was associated with an increased risk of T2D, with an odds ratio (OR) of 1.045, a 95% confidence interval (CI) ranging from 1.009 to 1.082, and a P-value of 0.015. This association was consistent in multivariate analyses, suggesting an independent effect of selenium on T2D risk after adjusting for confounders.
Conclusion
Our study presents novel evidence of a positive correlation between selenium intake and T2D risk, underscoring the importance of micronutrients in diabetes prevention and treatment strategies. Further research is necessary to confirm these findings and to clarify the specific biological mechanisms through which selenium influences diabetes risk.
... High blood selenium levels are linked to higher LDL and total cholesterol levels in American adults. Selenium was only linked to higher HDL cholesterol at low selenium levels [37]. Research of the entire population found a positive correlation between serum selenium levels and LDL, total, and total cholesterol [38]. ...
Background
There are limited epidemiological investigations of blood metal levels related to hyperlipidemia, and results indicating the association between blood lead (Pb), cadmium (Cd) and selenium (Se), and lipid biomarkers have been conflicting.
Methods
We included populations for which NHANES collected complete data. Multivariate logistic regression and subgroup analyses were conducted to ascertain the relationship between blood Pb, Cd, and Se levels and hyperlipidemia. Nonlinear relationships were characterized by smoothed curve fitting and threshold effect analysis.
Results
5429 participants in all, with a mean age of 53.70 ± 16.63 years, were included; 47.1% of the subjects were male, and 3683 (67.8%) of them had hyperlipidemia. After modifying for variables with confounders in a multivariate logistic regression model, we discovered a positive correlation between blood Pb and Se levels and hyperlipidemia (Pb: OR:2.12, 95% CI:1.56–2.88; Se: OR:1.84, 95% CI:1.38–2.45). Gender, age, smoking status, alcohol use status, hypertension, diabetes, and body mass index were not significantly linked with this positive correlation, according to subgroup analysis and interaction test (P for interaction>0.05). Positive correlations between blood Pb, Cd, and Se levels and the risk of hyperlipidemia have been found using smooth curve fitting.
Conclusions
This study demonstrates that higher blood levels of Pb, Cd, and selenium are linked to an increased risk of hyperlipidemia.
... Therefore, the lower concentration of selenium in the serum of residents of Poland or Estonia, where the selenium content is lower than in North American countries, should not be surprising [44,45]. Based on data from the National Health and Nutritional Examination Survey conducted in the United States, the average concentration of selenium in the serum of women aged 40 years and older was 134.7 μg/L [46]. Therefore, selenium supplementation can be justified in people whose microelement concentration is in the lowest tertile (£105.2 ...
Background: Selenium deficiency is an established risk factor for colorectal cancer. The aim of the present study was to determine selenium levels in blood samples obtained from colorectal cancer patients compared with the levels of this element in the blood of patients who had undergone hernia repair and cholecystectomy. Material/Methods: The study group consisted of 49 patients diagnosed with colorectal cancer at our institution. The comparison group consisted of 29 and 26 patients undergoing hernia repair and cholecystectomy, respectively. The histo-logical staging level was evaluated on a 4-grade scale. Serum selenium concentration was quantified by induc-tively coupled mass spectrometry using methane to reduce polyatomic interference. Results: Colorectal cancer patients had significantly lower serum selenium concentration than the comparison patients (67.24±15.55 μg/L vs 78.81±12.93 μg/L; P<0.001), and selenium concentration was below the reference range in a high percentage of colorectal cancer patients. However, among the colorectal cancer patients, no significant difference in cancer grading was observed according to selenium concentration (P=0.235). Serum sele-nium concentration in the patients was evaluated on the basis of 5 independent variables (R=0.6250): age (P=0.011), number of leukocytes (P=0.010), family history of cancer (P=0.045), dietary supplements (P=0.023), and exposure to chemical factors (P=0.057). Conclusions: This study supports findings from previous studies that low serum selenium levels are associated with colorec-tal cancer and that selenium deficiency may be a risk factor for colorectal cancer.
... The lipid profile parameters in both groups had shown an elevation in the levels of HDL after six weeks of intervention and follow up, but none of them showed a significant change, this is probably due to the short period of intervention and the small sample size, although selenium supplements can elevate the levels of HDL according to Laclaustra et al (38) . The study revealed a sharp increase in the levels of LDL and cholesterol of the control group which could be due to the demographic characteristics of the population and their daily consumption of large quantities of fatty food. ...
Pharmaceutical care interventions are a set of recommendations/interventions given by the pharmacist to improve therapeutic compliance, reduce complications, solve a drug therapy problem and improve patients' quality of life with chronic diseases by achieving patient satisfaction. The role of pharmaceutical care intervention in improving the condition of patients with hypothyroidism is still uncovered in Sulaimani city in Iraq, therefore, the current study aimed to evaluate the role of pharmaceutical care interventions in improving the outcome of psychological abnormalities in patients diagnosed with hypothyroidism. Fifty-eight patients were enrolled in the study and were randomly allocated into two groups: pharmaceutical care and the control group, both groups were interviewed by the pharmacist using a specific questionnaire. It is the fourth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) for assessing their psychological state at the beginning and the at the end of the study and data are recorded by the pharmacist. Blood samples were collected and utilized for analyzing the levels of thyroid function tests, lipid profile tests and blood glucose parameters at baseline and six weeks after. The pharmaceutical care group received all the education about their medications and how to minimize drug-related problems; improve the outcome and quality of life. Additionally, the pharmaceutical intervention included correcting some biochemical parameters. The study findings suggest that pharmaceutical care intervention and the pharmacist’s role over six-weeks period could improve the patient’s psychological condition. In addition, it can improve some biochemical parameters and quality of life significantly.
... Selenium (Se) is an essential trace element that plays a vital role in human and animal health by maintaining redox homeostasis, antioxidant defence, and anti-tumor and immune regulatory functions [7]. The average serum level of Se in adults is 13.67 mcg/dL [8], and the recommended daily intake (RDI) of Se for adults is 50-70 micrograms/day. Se is available in various forms, including multi-mineral/stand-alone supplements, selenomethionine, sodium selenite, and sodium selenate [9]. ...
Parkinson’s disease (PD) is the second most common progressive neurodegenerative disorder characterized by the accumulation of accumulated alpha-synuclein (α-Syn) in substantia nigra. Research has shown that selenium (Se) can protect neural cells through the actions of selenoproteins, including selenoprotein P (SelP) and selenoprotein S (SelS), which participate in endoplasmic reticulum-associated protein degradation (ERAD). In this study, we investigated the potential protective role of Se in a pre-clinical PD rat model.
We aimed to evaluate the therapeutic effects of Se administration in the 6-hydroxydopamine (6-OHDA) induced unilateral rat PD model. Male Wistar rats were utilised for unilateral PD animal model which were subjected to stereotaxic surgery and injected with 20 μg 6-OHDA/5 μl 0.2% ascorbate saline. After confirming the model, the rats were intraperitoneally injected with 0.1, 0.2, and 0.3 mg/kg of sodium selenite for 7 days. We then performed behavioral tests, including apomorphine-induced rotation, hanging, and rotarod tests. Following sacrifice, we analysed the substantia nigra area of the brain and serum for protein quantification, element analysis, and gene expression analysis.
Our results indicate that the administration of 0.3 mg/kg of Se improved the motor deficiency in hanging, rotarod, and apomorphine-induced rotational tests. While there was no significant improvement in the expression of α-Syn, Se increased the expression of selenoproteins. Additionally, levels of selenoproteins, Se, and α-Syn both brain and serum were re-established by the treatment, suggesting the role of Se on the α-Syn accumulation. Furthermore, Se improved PD-induced biochemical deficits by increasing the levels of SelS and SelP (p<0.005).
In conclusion, our findings suggest that Se may have a protective role in PD. 0.3 mg/kg dosage of Se increased the expression of selenoproteins, reduced the accumulation of α-Syn in the brain, and improved PD-induced motor deficits. These results suggest that Se may be a potential therapeutic option for PD treatment.
Graphical abstract
... Although the mechanisms underlying the relationship between high Se level and lipid metabolism are not clear, some studies have suggested that Se may play an important role in lipid peroxidation and lipoprotein metabolism. Although higher Se levels may increase oxidative stress (Brown and Arthur 2001), inconsistent results have been reported regarding the association of serum Se levels and BP (Nawrot, et al. 2007, Laclaustra, et al. 2010. While Se supplementation was found to reduce the binding activity of nuclear factor-k B (NFkB) and therefore lower oxidative stress in diabetic patients, some studies illustrated a non-linear positive association between serum Se levels and the prevalence of diabetes. ...
Minerals play a major role in regulating cardiovascular function. Imbalances in electrolyte minerals are frequent and potentially hazardous occurrences that may lead to the development of cardiovascular diseases (CVDs). Transition metals, such as iron, zinc, copper and selenium, play a major role in cell metabolism. However, there is controversy over the effects of dietary and supplemental intake of these metals on cardiovascular risk factors and events. Since their pro-oxidant or antioxidant functions can have different effects on cardiovascular health. While deficiency of these trace elements can cause cardiovascular dysfunction, several studies have also shown a positive association between metal serum levels and cardiovascular risk factors and events. Thus, a J-or U-shaped relationship between the transition minerals and cardiovascular events has been proposed. Given the existing controversies, large, well-designed, long-term, randomized clinical trials are required to better examine the effects of trace mineral intake on cardiovascular events and all-cause mortality in the general population. In this review, we discuss the role of dietary and/or supplemental iron, copper, zinc, and selenium on cardiovascular health. We will also clarify their clinical applications, benefits, and harms in CVDs prevention.
... There are conflicting epidemiological studies on the association between selenium and metabolic disorders. Higher selenium intake and blood levels have been associated with an elevated risk of diabetes [12][13][14][15][16], hyperlipidemia [17,18], hypertension [19], and NAFLD [20,21]. ...
... There are conflicting epidemiological studies on the association between selenium and metabolic disorders. Higher selenium intake and blood levels have been associated with an elevated risk of diabetes [12][13][14][15][16], hyperlipidemia [17,18], hypertension [19], and NAFLD [20,21]. ...
Background:
There is limited and conflicting evidence on the association between selenium and non-alcoholic fatty liver disease (NAFLD). Therefore, the present population-based cross-sectional study aimed to explore the relationship between dietary selenium intake and the risk of NAFLD.
Methods:
A total of 3026 subjects from the PERSIAN (Prospective Epidemiological Research Studies in IrAN) Kavar cohort study were included in the analysis. The daily selenium intake was evaluated using a semi-quantitative food frequency questionnaire, and energy-adjusted quintiles of selenium intake (µg/day) were calculated. NAFLD was defined as the fatty liver index (FLI) ≥ 60 or the hepatic steatosis index (HSI) > 36. The association between dietary selenium intake and NAFLD was evaluated using logistic regression analysis.
Results:
The prevalence rates of NAFLD were 56.4% and 51.9%, based on the FLI and HSI markers, respectively. The odds ratios (ORs) for FLI-defined NAFLD were 1.31 (95% confidence interval (CI): 1.01-1.70) and 1.50 (95% CI: 1.13-1.99) for the fourth and fifth quintiles of selenium intake, respectively, after adjustment for sociodemographic variables, smoking status, alcohol drinking, physical activity, and dietary factors (P trend = 0.002). There was also a similar association between selenium intakes and HSI-defined NAFLD (OR = 1.34 (95% CI: 1.03-1.75) for the fourth quintile and OR = 1.50 (95% CI: 1.12-2.01) for the fifth quintile of selenium intake) (P trend = 0.006).
Conclusion:
In this large sample study, we observed a weak positive association between dietary selenium intake and NAFLD risk.
... In addition to our findings, other studies using the NHANES population found positive associations between selenium and TC ( Christensen et al., 2015 ;Bleys et al., 2008 ;Laclaustra et al., 2010 ). The mechanisms involved in the sex specific relationship between serum selenium and lipids is also unclear. ...
Background: Abnormal lipid profiles in adolescents predict metabolic and cardiovascular diseases in adulthood. While seafood consumption is the primary source of mercury exposure, it also provides beneficial nutrients such as omega-3 fatty acids (O3FA). Prior studies indicate that blood total mercury (TBHg) has endocrine disrupting effects and may be associated with abnormal lipid profiles in adolescents. However, the impact of beneficial nutrients on this relationship has not been examined. Our study investigated the relationship of TBHg with dyslipidemia and lipid profiles and potential confounding and modification of these relationships by sex, body mass index (BMI), selenium and O3FA from seafood consumption. Methods: We examined 1,390 National Health and Nutrition Examination Survey participants 12-19 years of age from the 2011-2018 cycles. Using logistic and linear regression adjusted for survey design variables and stratified by sex a priori, we estimated the associations of TBHg and methylmercury with dyslipidemia, and with total cholesterol (TC), high (HDL-C) and low-density lipoprotein cholesterol (LDL-C) and triglycerides. Results: The geometric mean of TBHg in this adolescent population was 0.44 µg/L. After controlling for sociodemographic covariates, BMI, serum selenium, age at menarche (females only) and average daily intake of O3FA; TBHg was significantly associated with higher TC levels (β=3.34, 95% CI: 0.19, 6.50; p
... For example, the US selenium exposure tends to be higher than that in other Western countries, particularly European ones. According to the NHANES surveys, serum selenium levels in the US population are generally 130-140 μg/L [44][45][46], corresponding to a selenium intake of~86-93 μg/d [1,39]. ...
Background:
Selenium is an essential trace element with both beneficial and detrimental effects on health depending on dose and chemical form. Currently, there is debate on recommendations for selenium supplementation as a public health measure to improve immune function and reduce infectious disease susceptibility.
Objectives:
We performed a systematic review and meta-analysis of experimental studies assessing the effect of selenium supplementation on immunity-related outcomes in healthy people.
Methods:
We undertook a search of published and unpublished studies in literature databases such as PubMed/MEDLINE, Embase, and clinicaltrials.gov up to 17 October, 2022, and performed a meta-analysis comparing the effects on immunity-related outcomes between Se-supplemented versus control arms. Whenever possible we assessed the nonlinear relation using a dose-response approach.
Results:
9 trials were included, 5 in North America, and 4 in Europe, with a duration between 8 and 48 weeks and supplementation of both inorganic and organic selenium forms. Selenium supplementation did not substantially affect immunoglobulin or white blood cell concentrations, and the dose-response meta-analysis indicated that an increase in plasma selenium concentrations above 100 μg/L did not further increase IgA levels nor T cells. An inverted U-shaped relation emerged for NK cell count, with a lower number of these cells both below and above 120 μg/L. The only beneficial effect of selenium supplementation was the increased activity for NK lysis, but the available data did not permit dose-response analysis. Cytokine levels were substantially unaffected by selenium supplementation.
Conclusions:
Although some of the data suggested beneficial effects of selenium supplementation on immune function, the overall picture appears to be inconsistent and heterogeneous due to differences in trial duration and interventions, plus evidence of null and even detrimental effects. Overall, the evidence that we extracted from the literature in this systematic review does not support the need to supplement selenium beyond the recommended dietary intake to obtain beneficial effects on immune function. This trial was registered at PROSPERO (CRD42022312280).
... In contrast to the above studies, in other areas of the world such as the US, where Se levels are generally replete (averaging from 125.7 μg/L to 136.7 μg/L [4,30]), this striking correlation with breast cancer survival disappears [36,43]. Conversely, one would expect a profound increase on breast cancer mortality in geographical areas with low Se levels. ...
There is an urgent need for new and improved therapeutic strategies in breast cancer, which is the most common malignancy affecting women in the United States and worldwide. Selenium (Se) is an essential trace element of the human diet and plays a critical role in many aspects of human health. Clinical and epidemiological studies summarized here clearly demonstrate that Se status correlates with breast cancer survival. As a result, one way to curb breast cancer mortality would be via Se supplementation, especially in patients with severely deplete Se status. Se manifests its biological activity through incorporation into selenoproteins as selenocysteine. However, a better understanding of tissue-specific mechanisms and roles for selenoproteins in general is required. Additionally, many human selenoproteins harbor single nucleotide polymorphisms, which impact protein expression and activity and have been associated with cancer susceptibility or impacting survival. Increasing evidence indicates that these genetic variations impinge on the interactions between Se and breast cancer. This highlights the importance of integrating the Se status with genetic factors to fully define the benefit of Se in breast cancer. While Se supplementation would clearly benefit a subset of patients, this requires first the identification of at-risk patients and warrants validation through intervention trials.
... Several cross-sectional cohort studies conducted in the United States, China, France, Taiwan, and northern Italy have collectively found positive associations of Se level in the range of 124-147 μg/L and the prevalences of hyperglycemia and self-reported T2D [17,[50][51][52][53][54][55]. The recent Selenium Clinical Trial conducted in the United States found long-term (33 mos) supplementation with 200 μg Se/day in the form of Se-enriched yeast to older, post-surgical patients with colorectal adenoma being removed to increase their risk of clinically diagnosed T2D [56]. ...
Optimal selenium (Se) status is necessary for overall health. That status can be affected by food intake pattern, age, sex, and health status. At nutritional levels of intake, Se functions metabolically as an essential constituent of some two dozen selenoproteins, most, if not all, of which have redox functions. Insufficient dietary intake of Se reduces, to varying degrees, the expression of these selenoproteins. Recent clinical and animal studies have indicated that both insufficient and excessive Se intakes may increase risk of type 2 diabetes mellitus (T2D), perhaps by way of selenoprotein actions. In this review, we discuss the current evidence linking Se status and T2D risk, and the roles of 14 selenoproteins and other proteins involved in selenoprotein biosynthesis. Understanding such results can inform the setting of safe and adequate Se intakes.
... Numerous studies have examined the association between serum selenium levels and risk factors for heart disease, including lipid profile and blood pressure. Moreover, the results of some previous observational studies have shown that serum selenium levels are positively correlated with serum levels of LDL, TC and TG [19][20][21][22]. However, clinical trial studies have demonstrated contradictory results; for instance, a study by Rayman et al. showed that supplementation with 200 μg/day selenium for 6 months elicited a significant reduction in TC and LDL levels, but at higher doses had no significant effect on TC and LDL and it only caused a significant increase in serum HDL levels [23]. ...
Background
Previous studies evaluating the effects of selenium supplementation on lipid profile and blood pressure (BP) offer contradictory findings. This systematic review and meta-analysis assessed the effects of selenium supplementation on these lipid profile and BP.
Methods
In order to identify interrelated clinical trials, we performed a comprehensive literature search in the online databases, including PubMed, Scopus, Embase, and ISI web of science, up to December 2021.
Results
The analysis of the data established that selenium supplementation did not significantly affect TG level (WMD: -0.84 mg/dL; 95% CI: -4.74, 3.05, p= 0.671), LDL-C (WMD: 0.86 mg/dL; 95% CI: -1.21, 2.95, p= 0.416), and HDL-C (WMD: 0.3 mg/dL; 95% CI: -0.66, 1.27, p= 0.535). however, there was a significant reduction in TC levels following selenium supplementation (WMD: -2.11 mg/dL; 95% CI: -4.09, -0.13, p= 0.037). After subgroup analysis, when the baseline levels of LDL-C were <130 mg/dL, selenium supplementation elicited a significant increase in LDL-C levels (WMD: 2.89 mg/dL; 95% CI: 0.26, 5.51, p= 0.031). For BP, selenium supplementation significantly increased SBP (WMD: 2.02 mmHg; 95% CI: 0.50, 3.55, p= 0.009), while it had no significant effect on DBP (WMD: 0.39 mmHg; 95% CI: (-0.89, 1.68, p= 0.551).
Conclusion
Although our findings suggest selenium may have possible therapeutic effects in improving TC and VLDL, because of its negative effects on LDL and BP, selenium supplementation for cardiovascular protection should be recommended with caution.
... It can be assumed that there are similar mechanisms operating in FF in order to tightly control and limit Se status and selenoprotein levels, as both GPX3 and SELENOP were successfully detected in FF and correlated linearly to serum levels. However, the optimal concentrations in FF are unknown, as the samples analyzed were derived from European women with insufficient habitual intake, much in contrast to, e.g., subjects residing in North America where Se intake is higher due to better soil Se status [49,50]. ...
Female subfertility is a growing concern, especially in view of an increasing prevalence of polycystic ovary syndrome (PCOS). Assisted reproductive technologies (ART) offer a perspective for pregnancy, but the outcome rate is still suboptimal. The trace elements (TE), copper (Cu), selenium (Se), and zinc (Zn) are essential for fertility and development. We hypothesized that TE concentrations are related to oocyte quality and growth and affect pregnancy outcomes in women undergoing ART. Concentrations of TE were measured by total reflection X-ray fluorescence. Extracellular glutathione peroxidase 3 (GPX3) and selenoprotein P (SELENOP) were determined as additional Se biomarkers. Corresponding serum and follicular fluid (FF) samples were available from women with (n = 20) and without (n = 20) PCOS diagnosis undergoing hormone treatment within the ART procedure, respectively, and FF samples were classified into five groups based on morphological assessment. Serum showed higher TE concentrations than FF, and TE levels correlated positively between both matrices. Individual FF from the same women showed surprisingly high variability in TE concentration, and follicles without oocytes displayed the lowest TE concentrations. Both Se biomarkers GPX3 and SELENOP were present in FF and correlated positively to Se concentrations. Some notable relationships were observed between morphokinetic parameters, TE concentrations, and GPX3 activity. A slightly depressed serum Zn concentration was observed in PCOS. Our results indicate a direct relationship between TE in serum and FF, positive correlations between the three Se biomarkers in FF, and high variability between the FF from the same woman with the lowest TE concentrations in the follicles with the poorest quality. The differences observed in relation to PCOS diagnoses appear relatively minor. Collectively, the data support the notion that TE assessment of follicles may contribute to optimal oocyte selection and subsequently influence ART success.
... 17 Compared to the high serum Se levels in HC (> 150 ng mL À1 ), the serum Se levels in RA patients from the same area was not high but within a normal range (70-150 ng mL À1 ), comparable to reported normal Se levels in healthy individuals in many countries (China, 120 ng mL À1 ; Australia, 103 ng mL À1 ; the United States, 136.7 ng mL À1 ; UK, 86.9 ng mL À1 ). [39][40][41][42] Among RA patients, higher serum Se concentrations were associated with less severe disease, shown by lower DAS 28 and reduced CRP. The protective role of supranutritional Se in RA was validated in the mouse CIA model whereby Se supplementation increased serum Se concentrations, significantly delayed the arthritic onset, lowered clinical scores and ameliorated the severity of joint inflammation and damages. ...
Objective. The benefit of Se supplementation in rheumatoid arthritis (RA) has been tested in clinical trials, but results remain inconclusive. The objective of this study was to specifically investigate the potential benefit of supranutritional Se by examining human samples from an area with supranutritional Se intake and testing a mouse model of RA.
Methods. Peripheral blood mononuclear cells (PBMCs) from RA patients (N = 57) and healthy controls (HC, N = 71) from an area of supranutritional Se intake (Enshi, Hubei, China) were analysed by flow cytometry. Serum cytokine and Se levels were measured by cytometric beads array (CBA) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. With sufficient or supranutritional selenium intake, mice were induced with collagen-induced arthritis (CIA) and examined for disease activity and immunopathology. The influence of Se supplementation in the generation of RANKL-expressing osteoclastogenic CD4+ T cells was investigated by in vitro assays. Results. In Enshi city, HC showed the above-normal concentrations of serum Se concentrations while RA patients were enriched in the normal range (70–150 ng mL−1) or below. RA patients with higher Se levels demonstrated milder disease and lower levels of C-reactive protein, IL-6, RANKL and Th17 cells. In the mouse CIA model, supranutritional Se supplementation delayed disease onset, ameliorated joint pathology and reduced CD4+CD44+RANKL+ T cells. Se supplementation could suppress RANKL expression in cultured mouse Th17 cells. Conclusion. Supranutritional Se suppresses RANKL-expressing osteoclastogenic CD4+ T cells and could be beneficial to RA, which warrants formal testing in randomised clinical trials.
... Men with higher education level had lower selenium levels. One previous study using NHANES 1988-1994 data found an association with high school education and higher levels of selenium, whereas another NHANES 2003-2004 did not find a relationship in selenium levels with respect to education level [20,21]. These studies were from different years with inconsistent findings. ...
PurposeThe understanding of the role of plasma antioxidant levels in male fertility in the USA is limited. In a secondary analysis of the Males, Antioxidants, and Infertility (MOXI) randomized clinical trial, we sought to determine whether serum levels of vitamin E (α-tocopherol), zinc, and selenium were correlated with semen parameters and couple fertility outcomes.Methods
This study is a secondary analysis of the MOXI clinical trial. The primary endpoints in this secondary analysis include semen parameters, and DNA fragmentation and clinical outcomes including pregnancy and live birth. Analyses were completed using Wilcoxon’s rank-sum test and linear regression models.ResultsAt baseline, the analysis included plasma labs for vitamin E (n = 131), selenium (n = 124), and zinc (n = 128). All baseline plasma values were in the normal ranges. There was no association between selenium, zinc, or vitamin E levels and semen parameters or DNA fragmentation. Baseline antioxidant levels in the male partners did not predict pregnancy or live birth among all couples. Among those randomized to placebo, baseline male antioxidant levels did not differ between those couples with live birth and those that did not conceive or have a live birth.Conclusions
Among men attending fertility centers in the USA, who have sufficient plasma antioxidant levels of zinc, selenium, or vitamin E, no association was observed between vitamins and semen parameters or clinical outcomes in couples with male infertility. Higher levels of antioxidants among men with circulating antioxidants in the normal range do not appear to confer benefit on semen parameters or male fertility.
... Previous studies have confirmed that in China, inadequate Se intake was linked to Keshan disease and Kashin-back disease (2). Meanwhile, other studies have demonstrated that excessive Se intake was also associated with chronic diseases, such as hypercholesterolemia, hypertension, and diabetes (3)(4)(5)(6). ...
Background: The association between dietary selenium (Se) intake and osteoporosis-related fractures remains inconsistent. We aimed to examine the dose relationship between Se intake and incident fracture among Chinese adults.
Methods: The dietary data were retrieved from the China Health and Nutrition Survey conducted between 1991 and 2011, and 17,150 participants aged above 20 were included. A 3-day, 24-h recall of food intake was performed to assess cumulative average dietary Se intake. The fracture was based on self-report in each survey between 1997 and 2011. The association between Se intake and fracture was tested by Cox regression, and the non-linear association was examined by restricted cubic splines (RCS).
Results: There were 976 fracture cases during a mean of 10.2 years follow-up. In a fully adjusted Cox model, across the quartiles of Se intake, the hazard ratios (HRs) for fracture were 1.07 (95% CI .86–1.33), 1 (reference), 1.25 (95% CI 1.02–1.53), and 1.33 (95% CI 1.07–1.65). RCS showed a parabolic association (P non-linear = 0.037) between Se and fracture for men as well as a U-shape dose-response (P non-linear = 0.04) between Se and fracture for subjects living in highly urbanized areas.
Conclusion: In conclusion, there is a non-linear association between selenium intake and fracture, with higher intake associated with increased risk. The shape of the association varies by gender and urbanization level.
... The number of well-controlled and sufficiently powered randomized control trials (RCT) with supplemental Se is small, and the largest and most comprehensive ones have been conducted in the USA, where a large fraction of the population exhibits a replete Se status [57]. This is in contrast to the majority of subjects residing in other parts of the world [58]. ...
The trace element selenium (Se) is an essential part of the human diet; moreover, increased health risks have been observed with Se deficiency. A sufficiently high Se status is a prerequisite for adequate immune response, and preventable endemic diseases are known from areas with Se deficiency. Biomarkers of Se status decline strongly in pregnancy, severe illness, or COVID-19, reaching critically low concentrations. Notably, these conditions are associated with an increased risk for autoimmune disease (AID). Positive effects on the immune system are observed with Se supplementation in pregnancy, autoimmune thyroid disease, and recovery from severe illness. However, some studies reported null results; the database is small, and randomized trials are sparse. The current need for research on the link between AID and Se deficiency is particularly obvious for rheumatoid arthritis and type 1 diabetes mellitus. Despite these gaps in knowledge, it seems timely to realize that severe Se deficiency may trigger AID in susceptible subjects. Improved dietary choices or supplemental Se are efficient ways to avoid severe Se deficiency, thereby decreasing AID risk and improving disease course. A personalized approach is needed in clinics and during therapy, while population-wide measures should be considered for areas with habitual low Se intake. Finland has been adding Se to its food chain for more than 35 years—a wise and commendable decision, according to today’s knowledge. It is unfortunate that the health risks of Se deficiency are often neglected, while possible side effects of Se supplementation are exaggerated, leading to disregard for this safe and promising preventive and adjuvant treatment options. This is especially true in the follow-up situations of pregnancy, severe illness, or COVID-19, where massive Se deficiencies have developed and are associated with AID risk, long-lasting health impairments, and slow recovery.
... Similar to our findings, the intake of dietary supplements was found to be low among black African women residing in the UK [56]. However, without more research it is difficult to conclude whether black African women have lower Se levels due to their reduced supplement and dietary intake or because of other factors such as genetic make-up [57]. When examining birth outcomes, the current study found that the head circumference of neonates was significantly and negatively correlated with maternal serum Se levels in the total cohort (β = −0.164; ...
Selenium (Se) is an essential trace element and its deficiency in utero may affect fetus development and birth outcomes. The current study aimed to assess serum Se status at delivery and examine the possible association between Se levels and birth outcomes. The interaction of Se with selected essential and toxic elements as well as possible sex-dependent responses in utero were also evaluated. The negative association between Se levels and head circumference of neonates was evident in the total cohort (β = −0.164; p < 0.001) as well as in the pre-term and full-term cohorts. Significant positive correlations were found between maternal serum Se concentrations and zinc (Zn) and copper (Cu) in the total and regional cohorts. In the total cohort, the toxic elements lead (Pb) and arsenic (As) showed a negative correlation with Se levels, while mercury (Hg), aluminum (Al) and cadmium (Cd) showed a positive correlation. The study found a sex-dependent response in utero for Zn, Cu, Pb, Hg, and Al. The findings of the current study may inform reproductive health policy on Se status in South Africa and highlight the need for sensitive methods to measure Se intake during pregnancy and its complex interactions with other micronutrients and environmental pollutants.
... Previous cohort studies have demonstrated a solid bond between lower blood Se levels and the occurrence of hypertension, coronary heart disease, and ischemic stroke [11,[46][47][48][49][50]. In addition, some previous studies have shown a positive trend between higher blood Se levels and the occurrence of diabetes, metabolic syndrome, and dyslipidemia [13,[50][51][52][53][54][55][56][57]. Selenium deficiency has been reported in Polish patients with multiple sclerosis and pancreatic cancer [58][59][60], whereas no studies have been published with regard to patients with AIS in the adult Polish population. ...
Background:
In recent years, trace elements (TEs) have gained considerable attention in the course of treatment and diagnosis of ischemic stroke. The purpose of the conducted research was to determine the trace mineral status (Se, Cu, Zn, Cu/Zn ratio, and Cu/Se ratio) in patients with acute ischemic stroke compared to the population of healthy people in the northeastern region of Poland.
Materials and methods:
141 patients with acute ischemic stroke (AIS) and 69 healthy control subjects were examined. The serum concentrations of mineral components were assessed by the atomic absorption spectrometry method. Clinical parameters were updated based on medical records.
Results:
The serum Se and Zn concentrations were significantly decreased (p < 0.0001; p < 0.0001) in patients with AIS compared with healthy control subjects. However, no significant differences were revealed in terms of the serum Cu concentration (p = 0.283). As expected, we found that the serum Cu/Zn and Cu/Se molar ratios were significantly higher (p = 0.001; p < 0.0001) in patients with AIS compared with healthy control subjects.
Conclusions:
Disturbed metal homeostasis is a significant contributor to AIS pathogenesis. Furthermore, marked disruption of the serum Cu/Zn and Cu/Se molar ratios could serve as a valuable indicator of AIS patients' nutritional status and oxidative stress levels.
... In overall, the correlation between serum selenium level and metabolic risk factors for CVD appears to be positive. For example, increasing serum selenium levels is associated with increased risk factors for metabolic diseases such as LDL and HDL_; however, this association for triglyceride is U-shaped (24,38). It seems that this U-shaped relation can also be suggested for the level of selenium and cardiovascular health. ...
... Generally, a positive correlation could be observed between Se biomarkers (serum [38], hair [39], nail [38]) and lipid profile (total cholesterol/TC, lowdensity lipoprotein cholesterol/LDLC, triglycerides/TG) in Se-sufficient populations because of oxidative stress and inflammation via excessive Se [40,41]. In contrast, in Se deficiency or low-serum Se populations, no consistent associations could be observed [39,42]. Therefore, the aim of our study was to investigate urine, serum, and hair Se concentrations in urban elderly Chinese adults who were Se-supplemented and non-supplemented users, and the sensitive biomarker for Se-supplemented elderly populations in China will be proposed to monitor the Se status. ...
It is rapidly increasing to have selenium (Se) supplementation for urban elderly population in China since they are facing a widespread deficiency daily Se intake. However, until now, there is no low-cost, non-invasive, rapid, and reliable method to monitor the health improvement or risk for elderly Se-supplemented population in China. The present cross-sectional study (229 participants with older than 55 years old) performed in Beijing, China, revealed that the Se concentrations of non-supplementer users (n = 27) were 55 ± 23 μg/L in urine, 139.9 ± 102.3 μg/L in serum, and 487.6 ± 158.7 μg/kg in hair. But a significant increase on hair Se concentrations (615.4 ± 238.8 μg/kg) was observed for Se supplementer users (n = 202) (p < 0.05); there were no significant statistical differences in serum and urine between the Se-supplemented (n = 202) and Se non-supplemented groups (n = 27). This indicated the hair Se levels could be a more sensitive biomarker for Se-supplemented elderly population. Participants who consumed Se supplements for 7–12 months had the highest Se status based on hair and serum Se concentrations (p < 0.05). The present study also revealed that most elderly adults in Beijing just need to supplement 50 μg Se per day to achieve Se plateau status. Furthermore, hair Se levels were positively related with triglycerides/TG levels (p < 0.05) but not body mass index/BMI, total cholesterol/TC, and low-density lipoprotein cholesterol/LDL, implicating Se supplementation for Se sufficiency baseline in elderly population in Beijing likely posed health risk, especially on TG because of excessive Se oxidation stress. An ongoing monitoring of Se status via hair is still warranted to prevent future Se deficiency or excess in China.
Background
Evidence on the association between selenium and liver function parameters is limited and controversial.
Methods
Data on dietary selenium intake, blood selenium concentration, and liver function parameters were obtained from the National Health and Nutrition Examination Survey (NHANES) 2017–2020. Associations between selenium (dietary intake and blood concentration) and liver function parameters [alanine aminotransferase (ALT), aspartate aminotransferase (AST), the ALT/AST ratio, gamma-glutamyl transferase (GGT), and alkaline phosphatase (ALP)] were assessed using multivariate linear regression models. Subgroup analyses and interaction tests were conducted to examine differences in associations according to age, gender, body mass index (BMI), diabetes, and physical activity.
Results
The study included 6,869 participants after screening. The multivariate linear regression model revealed that dietary selenium intake was positively associated with ALT (β = 0.112, 95% CI = 0.041, 0.183) and the ALT/AST ratio (β = 0.002, 95% CI = 0.001, 0.004) after adjustment for covariates. Results of blood selenium concentration also showed that higher blood selenium levels were positively associated with ALT (β = 0.436, 95% CI = 0.308, 0.564), AST (β = 0.112, 95% CI = 0.015, 0.208), and the ALT/AST ratio (β = 0.012, 95% CI = 0.009, 0.015). However, ALP decreased with increasing blood selenium concentration (β = −0.207, 95% CI = −0.414, −0.000). In addition, we found significant differences in the effect of selenium on liver function parameters according to age, gender, and BMI.
Conclusion
Dietary selenium intake and blood concentration affect liver function parameters. These findings suggest that further research is needed to explore these associations to promote liver health and disease prevention.
Selenium (Se) is an essential trace element for humans and animals. Its necessity for plants is still under examination. Due to the contradictory nature of Se and its significance, it has received much interest in recent years. Se deficiency can be harmful to humans, yet almost a billion people are deficient. Its deficiency has been associated with cancers, impairment of organs, and a number of other ailments. The biofortification of plants and livestock is a guaranteed practice to increase human selenium consumption. Strategies such as foliar spraying, the direct application of Se in plants and Se feed, and injections in livestock have been employed. Se biofortification has been shown to have additional beneficial effects in plants and livestock. In plants, it has been reported to mitigate different types of stress and increase yield. In animal biofortification, Se has been shown to reduce the detrimental effects of ailments and promote healthy growth. Se biofortification, nevertheless, confronts a number of difficulties. For instance, the bulk of biofortified products must be prepared before consumption, lowering the Se concentration. The objective of this review is to convey the current understanding of the Se biofortification of plants and animals, as well as its difficulties, taking into account both the detrimental consequences of Se deficiency and benefits of Se biofortification.
Selenium (Se) is widely distributed in the total environment and people are commonly exposed to Se, while the potential effects and mechanisms of Se exposure on blood lipids have not been well established. This study aimed to assess the associations of urinary Se (SeU) with blood lipids and explore the potential mediating DNA methylation sites. We included 2844 non-smoke participants from the second follow-up (2017-2018) of the Wuhan-Zhuhai cohort (WHZH) in this study. SeU and blood lipids [i.e., total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL)] for all participants were determined. The associations of SeU with blood lipids were analyzed by generalized linear models. Then, we conducted the blood lipids related epigenome-wide association studies (EWAS) among 221 never smokers, and the mediation analysis was conducted to explore the potential mediating cytosine-phosphoguanine (CpG) sites in the above associations. In this study, the SeU concentration of the participants in this study was 1.40 (0.94, 2.08) μg/mmol Cr. The SeU was positively associated with TC and LDL, and not associated with TG and HDL. We found 131, 3, and 1 new CpG sites related to TC, HDL, and LDL, respectively. Mediation analyses found that the methylation of cg06964030 (within MIR1306) and cg15824094 (within PLCH2) significantly mediated the positive association between SeU and TC. In conclusion, high levels of Se exposure were associated with increased TC and LDL among non-smokers, and the methylation of MIR1306 and PLCH2 partly mediated Se-associated TC increase. These findings provide new insights into the effects and mechanisms of Se exposure on lipids metabolism and highlight the importance of controlling Se exposure and intake for preventing high blood lipids.
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 to 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.
Background
Type 1 diabetes (T1D) exhibited sex-specific metabolic status including oxidative stress with dynamic change of trace elements, which emphasized the importance of the evaluation of trace elements according to sex. Besides, the most significant characteristic, insulin auto-antibodies, could not be found in all T1D patients, which needed the auxiliary prediction of clinical parameters. And it would benefit the early detection and treatment if some high-risk groups of T1D could predict and prevent the occurrence of disease through common clinical parameters. Hence, there was an urgent need to construct more effective and scientific statistical prediction models to serve clinic better. This study aimed to evaluate the sex-specific levels of trace elements and the relationship between trace elements and clinical parameters in T1D, and construct sex-specific auxiliary prediction model combined with trace elements and clinical parameters.
Methods
A total of 105 T1D patients with negative insulin auto-antibodies and 105 age/sex-matched healthy individuals were enrolled in First Hospital of Jilin University. Inductively Coupled Plasma Mass Spectrometry was performed for the measurement of calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), iron (Fe), selenium (Se) in the serum, and the data of clinical parameters were received from medical record system. The lambda-mu-sigma method was used to evaluate the relationship between abnormal clinical parameters and trace elements. Training set and validation set were divided for the construction of predictable models in males and females: clinical parameters model, trace element model and the combined model (clinical parameters and trace elements). Goodness fit test, decision curve analysis and other related statistical methods were used to perform data analysis.
Results
Lower levels of Mg, Ca, Fe in the serum were found in T1D population in females compared with healthy population, while levels of Fe, Zn and Cu of serum in T1D individuals were higher than those of healthy population in males. Levels of serum Mg, Fe and Cu in T1D group were found with significant sex difference for (P<0.05), and the levels of Fe and Cu in serum of males were higher than those of females, level of serum Mg in males was lower than those of females. Levels of serum Mg and Zn showed fluctuation trend with increased numbers of abnormal clinical parameters (NACP) in males. Serum Zn in females showed consistent elevated trend with NACP; serum Se increased first and then decreased with NACP in males and females. The auxiliary prediction model (Triglyceride, Total protein, serum Mg) was found with the highest predicted efficiency in males (AUC=0.993), while the model in females (Apolipoprotein A, Creatinine, Fe, Se, Zn/Cu ratio) showed the best predicted efficiency (AUC=0.951). The models had passed the verification in validation set, and Chi-square goodness-of-fit test, DCA results both confirmed their satisfactory clinical applicability.
Conclusion
Sex-specific difference were found in serum Mg, Fe and Cu in T1D. The combination of triglyceride, total protein and serum Mg for males, and apolipoprotein A, creatinine, Fe, Se, Zn/Cu ratio for females could effectively predict T1D in patients with negative anti-bodies, which would provide alarm for the population with high-risk of T1D and serve the T1D prediction in patients with negative anti-bodies.
Purpose
To evaluate the association between dietary selenium intake and the risk of kidney stones in adults.
Materials and methods
We performed a cross-sectional analysis using data from 2007 to 2018 National Health and Nutrition Examination Survey (NHANES). Dietary intake information of 30,184 participants was obtained using first 24-h dietary recall interview, and kidney stones were presented by a standard questionnaire. The quartile analysis, stratified analysis and non-linearity analysis were used to estimate the association between dietary selenium intake and kidney stones after an adjustment for potential confounders.
Results
The multiple logistic regression indicated that the fourth quantile (Q4) of dietary selenium intake had a lower risk of kidney stones than the first quantile (Q1) in Model 3 (OR 0.82, P < 0.05). The stratified analyses indicated there were statistical differences between dietary selenium intake and kidney stones among younger (age < 50) (OR 0.65, P < 0.01), male (OR 0.73, P < 0.01) and overweight/obese (BMI ≥ 25.0) (OR 0.80, P < 0.05) individuals in Model 3. The non-linear relationship was founded between dietary selenium intake and kidney stones in all participants, younger, male and overweight/obese individuals after adjusting for confounding factors.
Conclusion
Our study revealed an inverse relation between the level of dietary selenium intake and the risk of kidney stones for the United States population, especially for younger (age < 50), male and overweight/obese (BMI ≥ 25.0) individuals. The study provides preliminary guidance on dietary selenium intake for the prevention of kidney stones in different populations. Further studies are required to confirm our findings and clarified the biological mechanisms.
Selenium (Se) is an essential micromineral that is incorporated into the active center of selenoproteins which play important roles in immune regulation, thyroid function, antioxidant defense, and glucose homeostasis. Se deficiency is commonly observed in patients of chronic illness, cancer, and severe trauma; Se supplementation to this group has been shown to provide clinical benefits including reduced mortality rates and better prognosis. However, there is a lack of consensus to determine Se adequacy and deficiency in terms of health and disease in the context of the local Taiwanese population. To obtain the normal Se range of the general adult Taiwanese by which to assess an individual’s Se status, studies reporting on plasma and serum Se values in Taiwanese adults from databases and available data from government-accredited clinical laboratories were gathered. After assessment for suitability against predefined criteria including sample size, subject characteristics, method of Se measurement, Se levels, and year of publication, six sources were included for subsequent mathematical calculations. The combined mean Se levels from a total of 5,508 subjects were 182.8 ± 124.3 µg/L. The range was estimated to be 58–307 µg/L, and Se levels between 100–270 µg/L were considered the normal range in Taiwanese adults, whereas Se levels < 100 µg/L were suggestive of deficiency and Se supplementation was recommended.
Selenium (Se) is an essential micromineral that is incorporated into the active center of selenoproteins which play important roles in regulating immune function, thyroid function, antioxidant defense, and glucose homeostasis. Dietary intakes and bodily levels of Se vary across countries due to geographical distribution of the mineral, dietary patterns, Se species, and genetic predispositions. Biomarkers such as serum/plasma Se, tissue Se, and bioactivity of selenoproteins to suggest Se status of an individual have been proposed and used in epidemiological and clinical studies. Beside vulnerable populations residing in Se-deficient regions, Se deficiency is found in patients of chronic illness, cancer, and those experiencing severe trauma; Se supplementation to this group has been shown to provide benefits including reduced mortality rates and better prognosis. However, there is a lack of consensus to determine Se adequacy and deficiency in terms of health and disease in the context of the local Taiwanese population. In this study, plasma and serum Se values reported from selected studies were pooled to calculate the normal Se range of the general adult Taiwanese. The calculated mean ± standard deviation values of Se level were 182.8 ± 124.3 μg/L (N = 5,508), and the range of Se levels was estimated to be approximately 58–307 mg/L. From this range, Se < 98.8 mg/L was suggestive of deficiency and required Se supplementation, whereas maintaining adequate levels of Se in the range of 125–183 mg/L would help to optimize its role in physiological well-being and disease prevention in Taiwanese adults.
Background
Limited studies have evaluated the joint influence of redox-related metals and genetic variants on metabolic pathways. We analyzed the association of 11 metals with metabolic patterns, and the interacting role of candidate genetic variation, in 1145 participants from the Hortega Study, a population-based sample from Spain.
Methods
Urine antimony (Sb), arsenic, barium (Ba), cadmium (Cd), chromium (Cr), cobalt (Co), molybdenum (Mo) and vanadium (V), and plasma copper (Cu), selenium (Se) and zinc (Zn) were measured by ICP-MS and AAS, respectively. We summarized 54 plasma metabolites, measured with targeted NMR, by estimating metabolic principal components (mPC). Redox-related SNPs (N = 291) were measured by oligo-ligation assay.
Results
In our study, the association with metabolic principal component (mPC) 1 (reflecting non-essential and essential amino acids, including branched chain, and bacterial co-metabolism versus fatty acids and VLDL subclasses) was positive for Se and Zn, but inverse for Cu, arsenobetaine-corrected arsenic (As) and Sb. The association with mPC2 (reflecting essential amino acids, including aromatic, and bacterial co-metabolism) was inverse for Se, Zn and Cd. The association with mPC3 (reflecting LDL subclasses) was positive for Cu, Se and Zn, but inverse for Co. The association for mPC4 (reflecting HDL subclasses) was positive for Sb, but inverse for plasma Zn. These associations were mainly driven by Cu and Sb for mPC1; Se, Zn and Cd for mPC2; Co, Se and Zn for mPC3; and Zn for mPC4. The most SNP-metal interacting genes were NOX1, GSR, GCLC, AGT and REN. Co and Zn showed the highest number of interaction with genetic variants associated to enriched endocrine, cardiovascular and neurological pathways.
Conclusions
Exposures to Co, Cu, Se, Zn, As, Cd and Sb were associated with several metabolic patterns involved in chronic disease. Carriers of redox-related variants may have differential susceptibility to metabolic alterations associated to excessive exposure to metals.
The protective effect of selenium against colorectal cancer or adenoma is still a controversial issue. Although there are well-described (pato)physiological protective mechanisms of selenium against colorectal cancer, the results of the studies from 1998–2018 are inconclusive and need to be considered in the future. Neither observational nor experimental studies present consistent results. Although the Cochrane review showed that well-designed randomized clinical trials (RCTs) presented no beneficial effect of selenium supplementation on cancer incidence, well-designed RCTs confirming the protective effect of selenium supplementation against colorectal adenoma or colorectal polyp recurrence have been found in subject-related literature.
In the reviewed studies, selenium concentration was measured in the blood serum/toenail or in diet. It is of great importance to highlight that blood selenium concentration depends on the concentration of this micronutrient in food, which in turn depends on selenium content in soil, bioavailability of selenium, which is different in various geographical regions, and forms of selenium. Selenium circulating in blood as a component of selenoproteins participates in oxidoreduction, thus reducing the risk of developing colorectal cancer. Despite this well-known protective mechanism against colorectal cancer occurrence, half of the reviewed studies did not confirm the protective properties of selenium.
To sum up, the current state of knowledge on the association between selenium and colorectal cancer or adenoma has revealed not only inconclusive results of the studies, but has also shown that there is a need to conduct more prospective studies focused on selenium supplementation and colorectal cancer as this research is limited.
High selenium concentrations were associated with cardiovascular diseases, type 2 diabetes, and central nervous disorders. The author examined the relation of serum selenium concentration with serum lipids levels with the use of the National Health and Nutrition Examination Survey (NHANES) 2017-2018. 759 adults aged more than 20 years old from NHANES 2017-2018 were examined in the analysis. Serum selenium was measured by mass spectrometry. Triglyceride, HDL cholesterol, and total cholesterol were measured through enzymatical methods. LDL cholesterol was calculated then. Comparing Q4 to Q1 of serum selenium, the multivariable adjusted average differences (95% CI) in triglyceride, HDL cholesterol, LDL cholesterol, and total cholesterol were 21.3 mg/dL (9.1, 33.4 mg/dL), 2.3 mg/dL (-0.6, 5.2 mg/dL), 6.3 mg/dL (-1.3, 13.9 mg/dL), 12.8 (95% CI: 4.2, 21.5 mg/dL), respectively. Hence, The increasing serum selenium concentration is associated with increasing triglyceride, total cholesterol, HDL cholesterol, and LDL cholesterol among US adults.
Susceptibility of patients with chronic obstructive pulmonary disease (COPD) to cardiovascular autonomic dysfunction associated with exposure to metals in ambient fine particles (PM2.5, particulate matter with aerodynamic diameter ≤2.5 µm) remains poorly evidenced. Based on the COPDB (COPD in Beijing) panel study, we aimed to compare the associations of heart rate (HR, an indicator of cardiovascular autonomic function) and exposure to metals in PM2.5 between 53 patients with COPD and 82 healthy controls by using linear mixed-effects models. In all participants, the HR levels were significantly associated with interquartile range increases in the average concentrations of Cr, Zn, and Pb, but the strength of the associations differed by exposure time (from 1.4% for an average 9 days (d) Cr exposure to 3.5% for an average 9 d Zn exposure). HR was positively associated with the average concentrations of PM2.5 and certain metals only in patients with COPD. Associations between HR and exposure to PM2.5, K, Cr, Mn, Ni, Cu, Zn, As, and Se in patients with COPD significantly differed from those in health controls. Furthermore, association between HR and Cr exposure was robust in COPD patients. In conclusion, our findings indicate that COPD could exacerbate difference in HR following exposure to metals in PM2.5.
The aim of this study was to investigate the association between daily selenium (Se) intake and postpartum weight retention (PPWR) among Chinese lactating women, and the impact of their Se nutritional status on infants’ physical development. Se contents in breast milk and plasma collected from total 264 lactating Chinese women at the 42 nd day postpartum were analyzed with ICP-MS. Daily Se intake was calculated based on plasma Se concentration. The dietary data of 24-hour record on 3 consecutive days was collected. Infant’s growth status was evaluated with WHO standards by Z-scores. Linear regression analyses and multinomial logistic regression were conducted to examine the impact of Se disequilibrium (including other factors) on PPWR and growth of infants, respectively. The results indicated that: 1) The daily Se intake of the subjects was negatively with their PPWR (B = -0.002, 95% CI -0.003, 0.000, P =0.039). 2) Both insufficient Se daily intake (B=-0.001, OR 95% CI 0.998, 1.000, P =0.014) and low level of Se in milk (B=-0.025, OR 95% CI 0.951, 0.999, P =0.021) had potential associations with their infants’ wasting, and low level of Se in milk (B=-0.159, OR 95% CI 0.743, 0.980, P =0.024) had a significant association with their infants’ overweight. In conclusion, the insufficient Se nutritional status of lactating Chinese women was firstly found as one possible influencing factor of their PPWR as well as low physical development of their offsprings.
Purpose
The veterans administration diabetes risk (VADR) cohort facilitates studies on temporal and geographic patterns of pre-diabetes and diabetes, as well as targeted studies of their predictors. The cohort provides an infrastructure for examination of novel individual and community-level risk factors for diabetes and their consequences among veterans. This cohort also establishes a baseline against which to assess the impact of national or regional strategies to prevent diabetes in veterans.
Participants
The VADR cohort includes all 6 082 018 veterans in the USA enrolled in the veteran administration (VA) for primary care who were diabetes-free as of 1 January 2008 and who had at least two diabetes-free visits to a VA primary care service at least 30 days apart within any 5-year period since 1 January 2003, or veterans subsequently enrolled and were diabetes-free at cohort entry through 31 December 2016. Cohort subjects were followed from the date of cohort entry until censure defined as date of incident diabetes, loss to follow-up of 2 years, death or until 31 December 2018.
Findings to date
The incidence rate of type 2 diabetes in this cohort of over 6 million veterans followed for a median of 5.5 years (over 35 million person-years (PY)) was 26 per 1000 PY. During the study period, 8.5% of the cohort were lost to follow-up and 17.7% died. Many demographic, comorbidity and other clinical variables were more prevalent among patients with incident diabetes.
Future plans
This cohort will be used to study community-level risk factors for diabetes, such as attributes of the food environment and neighbourhood socioeconomic status via geospatial linkage to residence address information.
Recent findings have raised concern about possible associations of high selenium exposure with diabetes and hyperlipidemia in the US, a population with high selenium status. In the UK, a population with lower selenium status, there is little data on the association of selenium status with cardio-metabolic risk factors in the general population. We examined the association of plasma selenium concentration with blood lipids in a nationally representative sample of British adults. A cross-sectional study was conducted among 1042 white participants (aged 19-64 y) in the 2000-2001 UK National Diet and Nutrition Survey. Plasma selenium was measured by inductively coupled-plasma mass spectrometry. Total and HDL cholesterol were measured in nonfasting plasma samples. Mean plasma selenium concentration was 1.10 +/- 0.19 micromol/L. The multivariate adjusted differences between the highest (> or =1.20 micromol/L) and lowest (<0.98 micromol/L) quartiles of plasma selenium were 0.39 (95% CI 0.18, 0.60) mmol/L for total cholesterol, 0.38 (0.17, 0.59) for non-HDL cholesterol, and 0.01 (-0.05, 0.07) for HDL cholesterol. Higher plasma selenium (i.e., > or =1.20 micromol/L) was associated with increased total and non-HDL cholesterol levels but not with HDL in the UK adult population. These findings raise additional concern about potential adverse cardio-metabolic effects of high selenium status. Randomized and mechanistic evidence is necessary to assess causality and to evaluate the impact of this association on cardiovascular risk.
Increasing evidence suggests that high selenium levels are associated with diabetes and other cardiometabolic risk factors.
We evaluated the association of serum selenium concentrations with fasting plasma glucose, glycosylated hemoglobin levels, and diabetes in the most recently available representative sample of the U.S. population.
We used a cross-sectional analysis of 917 adults > or = 40 years of age who had a fasting morning blood sample in the National Health and Nutrition Examination Survey 2003-2004. We evaluated the association of serum selenium, measured by inductively coupled plasma-dynamic reaction cell-mass spectrometry, and diabetes, defined as a self-report of current use of hypoglycemic agents or insulin or as fasting plasma glucose > or = 126 mg/dL.
Mean serum selenium was 137.1 microg/L. The multivariable adjusted odds ratio [95% confidence interval (CI)] for diabetes comparing the highest quartile of serum selenium (> or = 147 microg/L) with the lowest (< 124 microg/L) was 7.64 (3.34-17.46). The corresponding average differences (95% CI) in fasting plasma glucose and glycosylated hemoglobin were 9.5 mg/dL (3.4-15.6 mg/dL) and 0.30% (0.14-0.46%), respectively. In spline regression models, the prevalence of diabetes as well as glucose and glycosylated hemoglobin levels increased with increasing selenium concentrations up to 160 microg/L.
In U.S. adults, high serum selenium concentrations were associated with higher prevalence of diabetes and higher fasting plasma glucose and glycosylated hemoglobin levels. Given high selenium intake in the U.S. population, further research is needed to determine the role of excess selenium levels in the development or the progression of diabetes.
Secondary analyses of 2 randomized controlled trials and supportive epidemiologic and preclinical data indicated the potential of selenium and vitamin E for preventing prostate cancer.
To determine whether selenium, vitamin E, or both could prevent prostate cancer and other diseases with little or no toxicity in relatively healthy men.
A randomized, placebo-controlled trial (Selenium and Vitamin E Cancer Prevention Trial [SELECT]) of 35,533 men from 427 participating sites in the United States, Canada, and Puerto Rico randomly assigned to 4 groups (selenium, vitamin E, selenium + vitamin E, and placebo) in a double-blind fashion between August 22, 2001, and June 24, 2004. Baseline eligibility included age 50 years or older (African American men) or 55 years or older (all other men), a serum prostate-specific antigen level of 4 ng/mL or less, and a digital rectal examination not suspicious for prostate cancer.
Oral selenium (200 microg/d from L-selenomethionine) and matched vitamin E placebo, vitamin E (400 IU/d of all rac-alpha-tocopheryl acetate) and matched selenium placebo, selenium + vitamin E, or placebo + placebo for a planned follow-up of minimum of 7 years and a maximum of 12 years.
Prostate cancer and prespecified secondary outcomes, including lung, colorectal, and overall primary cancer.
As of October 23, 2008, median overall follow-up was 5.46 years (range, 4.17-7.33 years). Hazard ratios (99% confidence intervals [CIs]) for prostate cancer were 1.13 (99% CI, 0.95-1.35; n = 473) for vitamin E, 1.04 (99% CI, 0.87-1.24; n = 432) for selenium, and 1.05 (99% CI, 0.88-1.25; n = 437) for selenium + vitamin E vs 1.00 (n = 416) for placebo. There were no significant differences (all P>.15) in any other prespecified cancer end points. There were statistically nonsignificant increased risks of prostate cancer in the vitamin E group (P = .06) and type 2 diabetes mellitus in the selenium group (relative risk, 1.07; 99% CI, 0.94-1.22; P = .16) but not in the selenium + vitamin E group.
Selenium or vitamin E, alone or in combination at the doses and formulations used, did not prevent prostate cancer in this population of relatively healthy men.
clinicaltrials.gov identifier: NCT00006392.
Selenium, an essential micronutrient, has received considerable attention for its antioxidant properties. In addition, selenium may affect several cardiometabolic risk factors, such as glucose homeostasis and lipid concentrations. However, the effects of selenium intake on the lipid profile in selenium-replete populations, such as the United States, are largely unknown.
We examined the relation of serum selenium concentrations with serum lipids in a representative sample of US adults.
This was a cross-sectional analysis of 5452 men and women aged >/= 20 y participating in the third National Health and Nutrition Examination survey. Serum selenium was measured by atomic absorption spectrometry.
The multivariable adjusted differences in total cholesterol, LDL cholesterol, HDL cholesterol, apolipoprotein B (apo B), and apolipoprotein A-I (apo A-I) comparing the highest with the lowest quartile of serum selenium were 16.6 mg/dL (95% CI: 11.6, 21.4 mg/dL), 10.9 mg/dL (95% CI: 6.4, 15.4 mg/dL), 3.2 mg/dL (95% CI: 1.6, 5.0 mg/dL), 8.9 mg/dL (95% CI: 5.6, 12.2 mg/dL), and 6.9 mg/dL (95% CI: 1.7, 12.1 mg/dL), respectively. Participants in the highest quartile of serum selenium had 10% higher concentrations of triacylglycerols than did participants in the lowest quartile (ratio of triacylglycerol concentrations: 1.10; 95% CI: 1.05, 1.17). The difference in the ratios of LDL cholesterol to HDL cholesterol and apo B to apo A-I that compared the highest with the lowest selenium quartiles were 0.11 (95% CI: -0.02, 0.25) and 0.03 (95% CI: 0.00, 0.06), respectively.
Elevated serum selenium was associated with elevated serum concentrations of total cholesterol, LDL cholesterol, HDL cholesterol, triacylglycerols, apo B, and apo A-I among US adults, a selenium-replete population. Experimental studies are needed to determine cause and effect relations and the potential mechanisms underlying these associations.
Since high levels of selenium are used as cancer chemopreventive agents in animals and humans, a better understanding of the metabolism of subtoxic levels is desirable. Absorption from rat small intestine using in situ double perfusion, ligated intestinal segments, and brush border membrane vesicles (BBMV) was used to study selenium absorption. A level of 1.2 mM intraluminal selenite was required to inhibit 50 percent of the transepithelial transport of 3-0-methylglucose, indicating a high tolerance of the intestinal tract to selenium. The relative efficiency patterns for uptake of different selenocompounds during in vitro perfusion and in vivo ligated segments were identical with selenomethionine (SeMet) > selenate > selenite. In contrast, selenite was taken up most rapidly by BBMV, followed by SeMet and selenate in decreasing order. Ligated segments, double perfusion experiments, and uptake by BBMV indicated that selenium as selenodiglutathione or selenodicysteine was taken up faster than when present as selenite. Selenate and SeMet appeared in the vascular effluent largely unchanged, but selenite was metabolized extensively during absorption. Most of the selenium in plasma from subjects living in a high selenium area of China was associated with albumin, which is likely a result of high dietary intake of SeMet. Cracked fingernails and extensive hair loss were the symptoms of selenium toxicity in these individuals. Low adverse effect level of dietary (mean LOAEL) selenium was calculated to be about 1540 +/- 653 micrograms per day (or 28 micrograms/kg body weight) and the maximum safe dietary (mean NOAEL) selenium was calculated to be 819 +/- 126 micrograms per day (or 15 micrograms/kg body weight).
Despite the documented antioxidant and chemopreventive properties of selenium, studies of selenium intake and supplementation and cardiovascular disease have yielded inconsistent findings. The authors examined the effect of selenium supplementation (200 microg daily) on cardiovascular disease incidence and mortality through the entire blinded phase of the Nutritional Prevention of Cancer Trial (1983-1996) among participants who were free of cardiovascular disease at baseline (randomized to selenium: n = 504; randomized to placebo: n = 500). Selenium supplementation was not significantly associated with any of the cardiovascular disease endpoints during 7.6 years of follow-up (all cardiovascular disease: hazard ratio (HR) = 1.03, 95% confidence interval (CI): 0.78, 1.37; myocardial infarction: HR = 0.94, 95% CI: 0.61, 1.44; stroke: HR = 1.02, 95% CI: 0.63, 1.65; all cardiovascular disease mortality: HR = 1.22, 95% CI: 0.76, 1.95). The lack of significant association with cardiovascular disease endpoints was also confirmed when analyses were further stratified by tertiles of baseline plasma selenium concentrations. These findings indicate no overall effect of selenium supplementation on the primary prevention of cardiovascular disease in this population.
The purpose of this study was to examine the relationship between serum selenium levels and the prevalence of diabetes among U.S. adults.
We conducted a cross-sectional analysis of 8,876 adults > or =20 years of age who participated in the Third National Health and Nutrition Examination Survey. Diabetes was defined as the presence of a fasting plasma glucose > or =126 mg/dl, a self-report of a physician diagnosis of diabetes, or current use of insulin or oral hypoglycemic medication. Serum selenium was measured by atomic absorption spectrometry.
Mean serum selenium levels in participants with and without diabetes were 126.5 and 125.7 ng/ml, respectively. Age-, sex-, race-, and BMI-adjusted mean selenium levels were 126.8 ng/ml in participants with diabetes and 124.7 ng/ml in participants without diabetes (adjusted difference 2.1 ng/ml [95% CI 0.4-3.8]; P = 0.02). The multivariable adjusted odds ratio for diabetes comparing the highest to the lowest quintile of serum selenium was 1.57 [1.16-2.13]. However, the association between high serum selenium and the prevalence of diabetes was nonlinear, with no clear trend in quintiles 2-4.
In a probability sample of the U.S. population, high serum selenium levels were positively associated with the prevalence of diabetes. Until findings from prospective studies and randomized controlled trials are available, selenium intake, including selenium supplementation, should not be recommended for primary or secondary diabetes prevention in populations with adequate selenium status such as the U.S. population.
Findings from animal models suggest that selenium supplementation improves glucose metabolism.
To examine the effect of long-term selenium supplementation on the incidence of type 2 diabetes.
Secondary analysis of a randomized, double-blind, placebo-controlled trial.
Areas of low selenium consumption of the eastern United States.
1202 persons seen in dermatology clinics who did not have type 2 diabetes at baseline.
Oral administration of selenium, 200 microg/d, or placebo.
Incidence of type 2 diabetes.
During an average follow-up of 7.7 years (SD, 2.7), type 2 diabetes developed in 58 selenium recipients and 39 placebo recipients (incidence, 12.6 cases per 1000 person-years vs. 8.4 cases per 1000 person-years, respectively; hazard ratio, 1.55 [95% CI, 1.03 to 2.33]). The lack of benefit of selenium supplementation on the incidence of type 2 diabetes persisted in analyses stratified by age, sex, body mass index, and smoking status. An exposure-response gradient was found across tertiles of baseline plasma selenium level, with a statistically significantly increased risk for type 2 diabetes in the highest tertile of baseline plasma selenium level (hazard ratio, 2.70 [CI, 1.30 to 5.61]).
Diabetes was a secondary outcome in the parent trial. Diagnoses of diabetes were self-reported but were validated in most participants. The sample was mostly older and white.
Selenium supplementation does not seem to prevent type 2 diabetes, and it may increase risk for the disease. Click here for related information on selenium.
Selenium is incorporated into proteins as selenocysteine (Sec), which is dependent on its specific tRNA, designated tRNA([Ser]Sec). Targeted removal of the tRNA([Ser]Sec) gene (Trsp) in mouse hepatocytes previously demonstrated the importance of selenoproteins in liver function. Herein, analysis of plasma proteins in this Trsp knockout mouse revealed increases in apolipoprotein E (ApoE) that was accompanied by elevated plasma cholesterol levels. The expression of genes involved in cholesterol biosynthesis, metabolism and transport were also altered in knockout mice. Additionally, in two transgenic Trsp mutant mouse lines (wherein only housekeeping selenoprotein synthesis was restored), the expression of ApoE, as well as genes involved in cholesterol biosynthesis, metabolism and transport were similar to those observed in wild type mice. These data correlate with reports that selenium deficiency results in increased levels of ApoE, indicating for the first time that housekeeping selenoproteins have a role in regulating lipoprotein biosynthesis and metabolism.
Selenoprotein P (Sepp1) contains most of the selenium in blood plasma, and it is utilized by the kidney, brain, and testis as a selenium source for selenoprotein synthesis. We recently demonstrated that apolipoprotein E receptor-2 (ApoER2) is required for Sepp1 uptake by the testis and that deletion of ApoER2 reduces testis and brain, but not kidney, selenium levels. This study examined the kidney Sepp1 uptake pathway. Immunolocalization experiments demonstrated that Sepp1 passed into the glomerular filtrate and was specifically taken up by proximal tubule epithelial cells. Neither the C terminus selenocysteine-rich domain of Sepp1 nor ApoER2 was required for Sepp1 uptake by proximal tubules. Tissue ligand binding assays using cryosections of Sepp1-/- kidneys revealed that the proximal tubule epithelium contained Sepp1-binding sites that were blocked by the receptor-associated protein, RAP, an inhibitor of lipoprotein receptor-ligand interactions. Ligand blotting assays of kidney membrane preparations fractionated by SDS-PAGE revealed that Sepp1 binds megalin, a lipoprotein receptor localized to the proximal tubule epithelium. Immunolocalization analyses confirmed the in vivo co-localization of Sepp1 and megalin in wild type kidneys and demonstrated the absence of proximal tubule Sepp1 uptake in megalin null mice. These results demonstrate that kidney selenium homeostasis is mediated by a megalin-dependent Sepp1 uptake pathway in the proximal tubule.
Following the publication of the landmark trial of Clark et al. in 1996 that appeared to show that Se could reduce the risk of cancer, awareness of the importance of Se to human health has markedly increased. As a result, there is now much more aggressive marketing of Se supplements and functional foods, even in situations where additional consumption of Se is inappropriate. The present review addresses how Se gets into the food chain, the wide variability in Se content of foods and the very different levels of intake between countries and regions. Though it is clear that there are adverse consequences for health of both deficient and excessive intake, health effects at intermediate levels of intake are less certain. Thus it is difficult to define optimal intake which depends on a large number of factors, such as which functions of Se are most relevant to a particular disease state, which species of Se is most prominent in the Se source, which health condition is being considered, the adequacy or otherwise of intake of other nutrients, the presence of additional stressors, and lastly whether the ability to make selenoproteins may be compromised. These complexities need to be understood, particularly by policy makers, in order to make informed judgments. Potential solutions for increasing Se intake, where required, include agronomic biofortification and genetic biofortification or, for individuals, increased intake of naturally Se-rich foods, functional foods or supplements. The difficulties of balancing the risks and benefits in relation to Se intake are highlighted.
Background: Findings from animal models suggest that selenium supplementation improves glucose metabolism. Objective: To examine the effect of long-term selenium supplementation on the incidence of type 2 diabetes. Design: Secondary analysis of a randomized, double-blind, placebo-controlled trial. Setting: Areas of low selenium consumption of the eastern United States. Patients: 1202 persons seen in dermatology clinics who did not have type 2 diabetes at baseline. Intervention: Oral administration of selenium, 200 μLg/d, or placebo. Measurements: Incidence of type 2 diabetes. Results: During an average follow-up of 7.7 years (SD, 2.7), type 2 diabetes developed in 58 selenium recipients and 39 placebo recipients (incidence, 12.6 cases per 1000 person-years vs. 8.4 cases per 1000 person-years, respectively; hazard ratio, 1.55 [95% Cl, 1.03 to 2.33]). The lack of benefit of selenium supplementation on the incidence of type 2 diabetes persisted in analyses stratified by age, sex, body mass index, and smoking status. An exposure-response gradient was found across tertiles of baseline plasma selenium level, with a statistically significantly increased risk for type 2 diabetes in the highest tertile of baseline plasma selenium level (hazard ratio, 2.70 [Cl, 1.30 to 5.61]). Limitations: Diabetes was a secondary outcome in the parent trial. Diagnoses of diabetes were self-reported but were validated in most participants. The sample was mostly older and white. Conclusions: Selenium supplementation does not seem to prevent type 2 diabetes, and it may increase risk for the disease.
Binding of 7 5 Se to plasma proteins was studied in four cancer patients who received 200–250 μCi of 7 5 SeO32− (1.25 μg of selenium) intravenously for tumor scans. During the hour after injection, the 7 5 Se disappeared rapidly from the plasma. Gel filtration chromatography and dialysis experiments indicated that a large amount of the 7 5 Se returned to the plasma bound to protein between 1 and 6 h after injection. Up to 16% of the plasma 7 5 Se was found in very-low-density lipoproteins and low-density lipoproteins as early as 3 mikn after injection but very little 7 5 Se was found in high density lipoproteins. The very low density lipoprotein 7 5 Se activity declined very rapidly whereas low density lipoprotein 7 5 Se activity fell more slowly. Zonal ultracentrifugal studies of one subject's lipoproteins revealed a continuum of 7 5 Se-binding proteins from the very low density lipoprotein peak to the low density lipoprotein peak. Most of the 7 5 Se could be removed from the lipoproteins by denaturation with 8 M urea or treatment with 0.5 M mercaptoethanol. These treatments removed very little of the 7 5 Se from plasma collected 48 h after injection indicating a different type of binding of selenium in lipoproteins than in other plasma proteins.
This pilot study evaluated the feasibility and effectiveness of conducting a double-blind clinical trial for the prevention of lung cancer with selenium (Se) in Yunnan Tin Corporation, the People's Republic of China, where the incidence rates of lung cancer are extraordinarily high among the miners. Forty healthy miners were randomized to either 300 μg of Se in high Se malt cakes or an identical placebo of malt cakes daily for one year. Subjects consumed their usual daily diet. The low Se concentrations in plasma (0.05±0.008 μg/mL) and hair (0.442±0.085 μg/g) reflected their low dietary Se intake in the control subjects. In Se-supplemented group, the Se status was increased by 178% for serum and 194.8% for hair. The serum GSHpx activity was increased by 155.7%, whereas the lipid peroxide level was reduced by 74.5% compared to the placebo.
The results of UDS assay indicated that the lymphocyte DNA damage induced by ultraviolet irradiation and carcinogen 3,4-benzpyrene could be protected by Se supplementation. Se-supplementation did not affect the liver function test (SGPT), as well as the concentrations of hemoglobin, albumin, and cholesterol. Thus, daily intake of 300 μg Se in form of Se-malt as a chemopreventive measure is safe and effective to humans with low Se status.
Selenoprotein P (Sepp1) is a secreted protein that is made up of 2 domains. The larger N-terminal domain contains 1 selenocysteine residue in a redox motif and the smaller C-terminal domain contains the other 9 selenocysteines. Sepp1 isoforms of varying lengths occur but quantitation of them has not been achieved. Hepatic synthesis of Sepp1 affects whole-body selenium content and the liver is the source of most plasma Sepp1. ApoER2, a member of the lipoprotein receptor family, binds Sepp1 and facilitates its uptake into the testis and retention of its selenium by the brain. Megalin, another lipoprotein receptor, facilitates uptake of filtered Sepp1 into proximal tubule cells of the kidney. Thus, Sepp1 serves in homeostasis and distribution of selenium. Mice with deletion of Sepp1 suffer greater morbidity and mortality from infection with Trypanosoma congolense than do wild-type mice. Mice that express only the N-terminal domain of Sepp1 have the same severity of illness as wild-type mice, indicating that the protective function of Sepp1 against the infection resides in the N-terminal (redox) domain. Thus, Sepp1 has several functions. In addition, plasma Sepp1 concentration falls in selenium deficiency and, therefore, it can be used as an index of selenium nutritional status.
Selenium is an antioxidant micronutrient with potential interest for cardiovascular disease prevention. Few studies have evaluated the association between selenium and hypertension, with inconsistent findings. We explored the relationship of serum selenium concentrations with blood pressure and hypertension in a representative sample of the US population.
We undertook a cross-sectional analysis of 2638 adults > or =40 years old who participated in the 2003 to 2004 National Health and Nutrition Examination Survey. Serum selenium was measured by inductively coupled plasma-dynamic reaction cell-mass spectrometry. Hypertension was defined as blood pressure > or =140/90 mm Hg or current use of antihypertensive medication. Mean serum selenium was 137.1 microg/L. The multivariable adjusted differences (95% CIs) in blood pressure levels comparing the highest (> or =150 microg/L) to the lowest (<122 microg/L) quintile of serum selenium were 4.3 (1.3 to 7.4), 1.6 (-0.5 to 3.7), and 2.8 (0.8 to 4.7) mm Hg for systolic, diastolic, and pulse pressure, respectively. The corresponding odds ratio for hypertension was 1.73 (1.18 to 2.53). In spline regression models, blood pressure levels and the prevalence of hypertension increased with increasing selenium concentrations up to 160 microg/L.
High serum selenium concentrations were associated with higher prevalence of hypertension. These findings call for a thorough evaluation of the risks and benefits associated with high selenium status in the United States.
This secondary analysis of "Etude du Vieillissement Artériel" (EVA) study reports the effect of fibrates and statins on plasma selenium concentration and its 9-year change in free-living dyslipidemic elderly. Dyslipidemic patients were categorized in three sub-groups according to final low-density lipoprotein (LDL)-cholesterol level or hypolipidemic treatment: non-treated dyslipidemic (LDL-cholesterol >4.41 mmol/L, n=84); dyslipidemics who were treated exclusively by fibrates (n=47) or by statins (n=25) whatever their serum LDL-cholesterol concentration. The influence of lipid-lowering treatments on plasma selenium concentrations and its 9-year change was evaluated by analysis of variance (ANOVA) and multivariate linear regression models taking into account cardiovascular risk and changes in lipid-profile parameters. Multivariate linear regression indicated that the plasma selenium decline was associated with the longitudinal variation in LDL (beta=-0.039+/-0.019, p=0.04) and high-density lipoprotein (HDL)-cholesterol concentrations (beta=0.187+/-0.059, p=0.002) but not with triglycerides (beta=-0.018+/-0.031, p=0.57). During the 9-year follow-up, similar plasma selenium declines were observed in all the sub-groups (p=0.33) despite plasma selenium levels being higher in fibrate users and lower in statin users (p=0.0004). The mechanisms underlying these data are not yet totally understood, but considering the risk of selenium deficiency in the elderly and its relationship with poor health status further clinical trial is needed to verify the proposed hypotheses.
Whether an association, causative or not, exists between the level of serum selenium and the risk of ischaemic heart disease (IHD) remains unsettled. We investigated the issue in a cohort of 3387 males aged 53-74 years (mean 63). Based on information about health status, life-style and socioeconomic factors given in a prefilled comprehensive questionnaire, the men were interviewed and the information validated. Following the interview, they underwent a clinical examination and had a venous blood sample drawn for the determination of a number of biochemical characteristics. Three hundred and forty-six men were excluded due to prevalent cardiovascular disease, including stroke. During the next three years (1986-1989) 107 men (approximately 3%) suffered an IHD event; 25 events were fatal. Compared to others, men with serum selenium levels less than or equal to 1 mumol/l, approximately the lowest tertile, had a 70% increased risk of IHD, relative risk (RR) with 95% confidence limits was 1.70 (1.14-2.53). After multivariate adjustment for cholesterol, social class, smoking and age, RR was 1.55 (1.00-2.39). Serum selenium level was significantly (P less than 0.05), but not strongly, correlated with a number of IHD risk factors: serum cotinine, tobacco smoking, social class, alcohol consumption, total cholesterol, hypertension, age and physical inactivity. Body mass index, HDL-cholesterol and triglycerides were not significantly associated with serum selenium. We conclude that middle-aged and elderly Danish men with serum selenium less than or equal to 1 mumol/l had a significantly increased risk of ischaemic heart disease. This association was not explained by the interrelationship of serum selenium and major cardiovascular risk factors.
This pilot study evaluated the feasibility and effectiveness of conducting a double-blind clinical trial for the prevention of lung cancer with selenium (Se) in Yunnan Tin Corporation, the People's Republic of China, where the incidence rates of lung cancer are extraordinarily high among the miners. Forty healthy miners were randomized to either 300 micrograms of Se in high Se malt cakes or an identical placebo of malt cakes daily for one year. Subjects consumed their usual daily diet. The low Se concentrations in plasma (0.05 +/- 0.008 microgram/mL) and hair (0.442 +/- 0.085 microgram/g) reflected their low dietary Se intake in the control subjects. In Se-supplemented group, the Se status was increased by 178% for serum and 194.8% for hair. The serum GSHpx activity was increased by 155.7%, whereas the lipid peroxide level was reduced by 74.5% compared to the placebo. The results of UDS assay indicated that the lymphocyte DNA damage induced by ultraviolet irradiation and carcinogen 3,4-benzpyrene could be protected by Se supplementation. Se-supplementation did not affect the liver function test (SGPT), as well as the concentrations of hemoglobin, albumin, and cholesterol. Thus, daily intake of 300 micrograms Se in form of Se-malt as a chemopreventive measure is safe and effective to humans with low Se status.
The association between serum selenium concentration and a number of coronary heart disease risk factors is studied in 364 males from southern Italy participating in the Olivetti Heart Study. Selenium correlates positively and significantly with serum cholesterol (r = 0.120; P = 0.022), and this positive association persists after adjustment for age and body mass index. Selenium levels in heavy smokers are lower than both light smokers and current non-smokers, but these differences do not reach statistical significance. Selenium is not significantly associated with any of the other CHD risk factors (e.g., triglycerides, HDL cholesterol, blood pressure, age, and body mass index). It is hypothesized that the association between selenium and serum cholesterol reported in this and previous studies could be due to dietary interrelationships between selenium intake and foods that affect serum cholesterol concentrations.
The association between the concentration of selenium in serum and risk factors for cardiovascular disease was studied in 467 apparently healthy men and women. The concentration of selenium in serum was significantly higher in men than in women (1.63 versus 1.51 mumol/L) (p less than 0.001). A statistically significant positive correlation between serum selenium concentration and total cholesterol was found in women, but not in men. No other statistically significant correlations were observed with the major risk factors for coronary heart disease. There were indications that high consumption of fish, coffee and bread were associated with increased serum selenium levels, but the differences did not reach statistical significance. Our findings suggest that serum selenium concentrations in the range 1.2-2.0 mumol/L are not associated with major risk factors for cardiovascular disease.
In a prospective study a low serum selenium level was associated with an increased risk of coronary death and myocardial infarction (1). This study examined the relationship of serum selenium concentration with serum glutathione peroxidase activity (GSH-Px) and lipids connected with coronary atherogenesis. Serum selenium levels in 26 healthy subjects were positively correlated with GSH-Px activities and high-density lipoprotein cholesterol concentrations. Selenium supplementation increased serum selenium level and the GSH-Px activity in a double-blind evaluation. The high-density lipoprotein cholesterol/cholesterol ratio increased during selenium supplementation in a group excluding subjects with a low cholesterol. The results suggest a link running from low serum selenium to reduced high-density lipoprotein cholesterol, and further to high coronary risk. Selenium supplementation may in subjects with low selenium reduce the the risk of coronary heart disease.
The general objective of the Etude du Viellissement Arterial (EVA) program is to follow vascular aging and the decline in cognitive functions at the cerebrovascular level longitudinally over a 4-year period. One of the specific objectives of this EVA study is to examine epidemiologically the relationship between the markers of oxidative stress (lipid peroxidation), the antioxidant micronutrient status (particularly of selenium, vitamin E, and the carotenoids) and the prevalence of chronic disorders occurring during the pre-aging period.
1389 subjects aged from 59 to 71 years were studied.
The concentration of plasma lipid peroxides was higher than in young adults (2.91 +/- 0.38, men; 2.97 +/- 0.40, women (mumol/l). On the other hand, plasma Se (1.09 +/- 0.21, men; 1.10 +/- 0.19, women (mumol/l)), erythrocyte vitamin E (5.32 +/- 1.29, men; 5.52 +/- 1.28, women (mumol/l)), and total plasma carotenoids (2.19 +/- 0.98, men; 3.07 +/- 1.33, women (mumol/l)) were comparable to values in young adults. In our cohort, 40% of subjects had unremarkable medical histories. The disorders most often encountered were lipemia (29.8% of men, 36.1% of women), and hypertension (28.9% of men, 30.4% of women).
Se and vitamin E levels were raised in cases of lipemia, especially in those treated with fibrates. The mechanism of the increase is unknown. In hypertensives and diabetics, there was a decrease in total carotenoids associated with increased peroxidative risk.
The essential trace mineral, selenium, is of fundamental importance to human health. As a constituent of selenoproteins, selenium has structural and enzymic roles, in the latter context being best-known as an antioxidant and catalyst for the production of active thyroid hormone. Selenium is needed for the proper functioning of the immune system, and appears to be a key nutrient in counteracting the development of virulence and inhibiting HIV progression to AIDS. It is required for sperm motility and may reduce the risk of miscarriage. Deficiency has been linked to adverse mood states. Findings have been equivocal in linking selenium to cardiovascular disease risk although other conditions involving oxidative stress and inflammation have shown benefits of a higher selenium status. An elevated selenium intake may be associated with reduced cancer risk. Large clinical trials are now planned to confirm or refute this hypothesis. In the context of these health effects, low or diminishing selenium status in some parts of the world, notably in some European countries, is giving cause for concern.
Previous observations have suggested that lipoproteins may be involved in the transport of selenium in humans. To further investigate this question, selenium was measured in lipoprotein fractions isolated from plasma of healthy adults. A gas chromatographic-mass spectrometric method using the isotopic dilution technique was developed to ensure a reliable measurement of low amounts of selenium. About 3% of total plasma selenium was bound to lipoproteins, mainly to the LDL fraction. After solvent fractionation of LDL and HDL, the major part of the selenium was recovered in the protein extract, suggesting that it may be incorporated in apolipoproteins. The exact form of Se is not yet clearly established. Considering the different Se compounds found in proteins, it is postulated to be selenomethionine, and/or participating in a selenium-sulphur bond. This could explain why the amount of selenium bound to apolipoprotein B in LDL was about twice that which could be expected from a random substitution of selenomethionine for methionine.
Epidemiologic studies and case reports have shown that chronic exposure to selenium compounds is associated with several adverse health effects in humans. An early toxic effect of selenium is on endocrine function, particularly on the synthesis of thyroid hormones following dietary exposure of around 300 micrograms Se/d, and on the metabolism of growth hormone and insulin-like growth factor-1. Other adverse effects of selenium exposure can be the impairment of natural killer cells activity and at higher levels, hepatotoxicity and gastrointestinal disturbances. Dermatologic effects, such as nail and hair loss and dermatitis, occur after exposure to high levels of environmental selenium. Assessing the toxicity and morbidity after long-term exposure to environmental selenium is difficult: neurotoxicity, particularly the degeneration of motor neurons leading to increased risk of amyotrophic lateral sclerosis, might occur after chronic exposure to both organic and inorganic selenium compounds. The results of laboratory investigations and cohort studies suggest that selenium species exhibit a bivalent effect in cancer, either increasing or decreasing risk. Current environmental selenium exposure limits appear to be inadequate for averting adverse health effects.
Statins are possibly the most effective drugs for the prevention and treatment of hypercholesterolaemia and coronary heart disease. They are generally well tolerated, however, they do cause some unusual side-effects with potentially severe consequences, most prominently myopathy or rhabdomyolysis and polyneuropathy. We noted that the pattern of side-effects associated with statins resembles the pathology of selenium deficiency, and postulated that the mechanism lay in a well established, but often overlooked, biochemical pathway--the isopentenylation of selenocysteine-tRNA([Ser]Sec). A negative effect of statins on selenoprotein synthesis does seem to explain many of the enigmatic effects and side-effects of statins, in particular, statin-induced myopathy.
Antioxidant micronutrients have been reported to be associated with an improvement in the blood profile, but the results are not consistent. The aim of the present study was to assess the effects of antioxidant supplementation on changes in the serum lipid profile of adult participants in the SU.VI.MAX study. French adults (n = 12,741: 7,713 females aged 35-60 yr, and 5,028 males aged 45-60 yr) received daily antioxidant supplementation (120 mg vitamin C, 30 mg vitamin E, 6 mg beta-carotene, 100 microg selenium, and 20 mg zinc) or a matching placebo. Median follow-up time was 7.5 yr. After 7.5 yr, no effect of supplementation on total cholesterol was observed in men or women after adjusting for baseline total cholesterol levels and lipid-lowering medications. The prevalence of hypercholesterolemia (> or =6.5 mmol/L) showed a trend toward being higher in women who received supplements compared with those who received the placebo (P= 0.06). In both sexes, the group receiving supplements exhibited higher mean serum TG concentrations than did the placebo group (P= 0.06 in men; P= 0.05 in women). The prevalence of hypertriglyceridemia (> or =2.3 mmol/L) was also significantly higher in men who received supplements (P= 0.03), but not in women. Our results suggest than long-term daily supplementation with low doses of beta-carotene, vitamins C and E, selenium, and zinc does not result in an improved lipid profile and could even adversely affect some blood lipids, possibly with a higher risk of hyperlipidemia in women.
A population-based study of a quantitative trait may be seriously compromised when the trait is subject to the effects of a treatment. For example, in a typical study of quantitative blood pressure (BP) 15 per cent or more of middle-aged subjects may take antihypertensive treatment. Without appropriate correction, this can lead to substantial shrinkage in the estimated effect of aetiological determinants of scientific interest and a marked reduction in statistical power. Correction relies upon imputation, in treated subjects, of the underlying BP from the observed BP having invoked one or more assumptions about the bioclinical setting. There is a range of different assumptions that may be made, and a number of different analytical models that may be used. In this paper, we motivate an approach based on a censored normal regression model and compare it with a range of other methods that are currently used or advocated. We compare these methods in simulated data sets and assess the estimation bias and the loss of power that ensue when treatment effects are not appropriately addressed. We also apply the same methods to real data and demonstrate a pattern of behaviour that is consistent with that in the simulation studies. Although all approaches to analysis are necessarily approximations, we conclude that two of the adjustment methods appear to perform well across a range of realistic settings. These are: (1) the addition of a sensible constant to the observed BP in treated subjects; and (2) the censored normal regression model. A third, non-parametric, method based on averaging ordered residuals may also be advocated in some settings. On the other hand, three approaches that are used relatively commonly are fundamentally flawed and should not be used at all. These are: (i) ignoring the problem altogether and analysing observed BP in treated subjects as if it was underlying BP; (ii) fitting a conventional regression model with treatment as a binary covariate; and (iii) excluding treated subjects from the analysis. Given that the more effective methods are straightforward to implement, there is no argument for undertaking a flawed analysis that wastes power and results in excessive bias.
Little is known about the long-term effects of garlic or micronutrient supplementation on total, HDL, and LDL cholesterol in disease-free persons.
We aimed to assess the effects of long-term supplementation with garlic and micronutrients and of short-term amoxicillin and omeprazole treatment on serum total, HDL, and LDL cholesterol in a rural Chinese population.
We conducted a randomized, double-blind, placebo-controlled, 2 x 2 x 2 and 2 x 2 factorial study of precancerous gastric lesions in 3411 subjects in Linqu County, Shandong Province, China. Thirty-four subjects were randomly selected from each of 12 treatment strata. Sera were analyzed at 3.3 and 7.3 y to measure effects on total, HDL, and LDL cholesterol after 2-wk twice-daily treatment with 1 g amoxicillin and 20 mg omeprazole and supplementation throughout the study with 1) 2 capsules twice daily, each containing 200 mg aged garlic extract and 1 mg steam-distilled garlic oil, or 2) twice-daily micronutrient capsules containing 250 mg vitamin C, 100 IU vitamin E, and 37.5 mg selenium.
Regressions adjusted for covariates indicated increases of 0.22 mmol total cholesterol/L (P = 0.01) and 0.19 mmol LDL/L (P = 0.02) after 7.3 y of micronutrient supplementation, but no effect of garlic supplementation or short-term amoxicillin and omeprazole treatment.
In this rural Chinese population with low meat intake and moderate cholesterol concentrations, long-term garlic supplementation had no effect on lipid profiles, whereas micronutrient supplementation was associated with small but significant increases in total and LDL-cholesterol concentrations at 7.3 y.
The importance of selenium to human health
- Rayman
Rayman MP. The importance of selenium to human health. Lancet 2000;356(9225):233–241.
[PubMed: 10963212]
National Center for Health Statistics (NCHS) National Health and Nutrition Examination Survey. Hyattsville, MD: U.S.: Department of Health and Human Services
Centers for Disease Control and Prevention (CDC). National Center for Health Statistics (NCHS).
National Health and Nutrition Examination Survey. Hyattsville, MD: U.S.: Department of Health
and Human Services, Centers for Disease Control and Prevention; 2003–2004 [accessed 9 September
2008]. Reprint: http://www.cdc.gov/nchs/nhanes.htm
Serum selenium and diabetes in U.S. adults.
- Bleys J.
- Navas-Acien A.
- Guallar E.
Bleys J, Navas-Acien A, Guallar E. Serum selenium and diabetes in U.S. adults. Diabetes Care 2007;30
(4):829–834. [PubMed: 17392543]
Serum selenium and diabetes in U.S. adults
- Bleys