Sexual dimorphism in selenium deficiency is associated with metabolic syndrome and prevalence of heart disease

The association of selenium exposure with the odds of metabolic syndrome: a dose-response meta-analysis

BACKGROUND

Selenium is a key regulator of metabolic homeostasis. It has been proposed that exposure to selenium might be associated with metabolic syndrome (MetS). However, the results are contradictory. This meta-analysis was carried out to analyze the relationships between selenium levels in biological samples and odds of Mets.

METHODS

We searched Scopus and PubMed databases up until September 2024 to identify relevant studies. Odds ratio (OR) and 95% confidence interval was used to pool the data using a random effects model.

RESULTS

The meta-analysis encompassed 18 observational studies involving 21,481 participants. It found that higher selenium exposure was related to an elevated likelihood of MetS (OR = 1.30, 95% CI = 1.12-1.51), even after controlling for covariates, such as smoking, age, alcohol consumption, and physical activity. Heterogeneity was significant among the studies (I² = 88.9%, P = 0.001). While elevated serum selenium levels linked to a higher odds of MetS, no such relationship was observed for selenium in urine or toenails. Subgroup analyses indicated that this association was evident only in females (OR = 2.0, 95% CI = 1.17-1.43) and particularly pronounced in individuals aged ≥ 50 years. A dose-response relationship was identified, showing a 6% increase in MetS odds for each additional 10 µg/L of serum selenium, with the odds rising non-linearly when serum levels surpassed 80 µg/L.

CONCLUSIONS

This study suggests that selenium may associated with the odds of MetS, following a dose-response relationship.

Association between Heavy metals and triglyceride-glucose-related index: a mediation analysis of inflammation indicators

BACKGROUND

In cardiovascular diseases (CVD) and insulin resistance (IR), elevated blood lipids and glucose are common. These abnormalities accelerate atherosclerosis and may impair insulin signaling via oxidative stress and inflammation. The triglyceride-glucose (TyG) index is a cost-effective marker for assessing IR and CVD risk, reflecting insulin resistance and early atherosclerosis. However, research on factors affecting the TyG index, especially mixed heavy metal exposure, is limited. Heavy metals might alter the TyG index by inducing oxidative stress and inflammation, affecting lipid and glucose metabolism. This study explores the link between heavy metal exposure and TyG index changes, focusing on inflammation's mediating role, aiming to offer new strategies for CVD and IR prevention and management.

METHOD

This research explores the association between heavy metal concentrations and TyG indicators, drawing on data from the National Health and Nutrition Examination Survey spanning 2011 to 2016. It employs a range of statistical approaches, such as linear and non-linear analyses, multiple linear regression, weighted quantile sum regression, and Bayesian kernel machine regression. Additionally, a mediation analysis investigates the role of inflammation in modifying the effects of heavy metal exposure.

RESULT

The research analyzed data from a sample of 2,050 individuals, finding notable links between mixed heavy metals and variations in TyG markers. Specifically, the presence of heavy metal mixtures was associated with significant increases in these indicators. Additionally, six inflammatory markers were identified that act as intermediaries in the process leading from heavy metal exposure to alterations in TyG indicators.

CONCLUSION

The study establishes a clear association between heavy metal and adverse changes in TyG markers, influenced in part by inflammation. These insights highlight the urgent need for improved monitoring of environmental health and specific strategies to decrease heavy metal exposure, thus lessening their harmful impact on cardiovascular health. The research enhances understanding of the dynamic interactions between environmental exposures and metabolic health, laying groundwork for public health initiatives aimed at curtailing chronic disease risks linked to heavy metals.

Erythrocyte Selenium as a Potential Key Indicator for Selenium Supplementation in Low-Selenium Populations: A Selenium Supplementation Study Based on Wistar Rats

BACKGROUND

Selenium (Se) is an essential trace element for maintaining human health, with significant antioxidant and immunoregulatory functions. Inadequate Se intake may be associated with Keshan disease, Kashin-Beck disease, and hypothyroidism. However, effective indicators for scientifically guiding Se supplementation in Se-deficient populations are still lacking.

OBJECTIVES

This study aims to explore the dynamic distribution of Se across various nutritional biomarkers and major organs in rats through a Se supplementation experiment, as well as the pairwise correlations between them, in order to identify reliable nutritional indicators for evaluating Se levels in the body.

METHODS

Se levels in hair, blood, and major tissues and organs were determined by atomic fluorescence spectrometry, and glutathione peroxidase (GSH-Px) levels were measured using an ELISA.

RESULTS

Se supplementation significantly increased Se levels in rat blood, hair, and major organs, as well as GSH-Px levels in blood. Se primarily accumulated in the liver and kidneys, followed by myocardium, spleen, and muscles. Serum and plasma Se were found to be the best indicators of short-term Se intake, while erythrocyte Se levels showed a stronger correlation with Se levels in tissues and organs, making it a better marker for assessing long-term Se nutritional status compared to hair Se.

CONCLUSIONS

This study demonstrates the potential of erythrocyte Se levels as an indicator for evaluating long-term Se nutritional status, providing scientific evidence for Se nutritional assessments.

Genetic Determinants of Selenium Availability, Selenium-Response, and Risk of Polycystic Ovary Syndrome

Selenium is a trace element and its deficiency has been associated with the risk of PCOS, a multifactorial syndrome that affects a large number of women worldwide. Several databases and literature were searched to find out genetic variants of the genes involved in selenium uptake, metabolism, and regulation which may be significantly associated with the risk of PCOS through Se-related pathways. Genes that require selenium for their biological actions to perform were also shortlisted. A total of eighteen significantly associated genes with forty-four variants were identified as candidate variants that could play a potential role in the modulation of PCOS risk among the study population. The genetic variant distribution data was available in-house and was obtained through a GWAS study of the North India population. In silico tools were applied to understand the functional impact of these variants. Three variants namely LDLR (rs2228671), TNF (rs1041981), and SAA2 (rs2468844) are strongly associated with PCOS risk and have a functional impact on encoded protein. Certain variants of Se uptake genes such as DIO1, GPX2, TXNRD1, DIO2 and GPX3 are also significantly associated with the risk of PCOS development. "C" allele of the Se transporter gene SELENOP (rs9686343) significantly increases PCOS risk. Other potential genes require selenium for their biological actions and are involved in the inflammatory, antioxidant response, and energy homeostasis signaling pathways. Thus, genetic variants of the population may affect the Se availability in the body. Also, deficiency of Se effects may get modulated due to underlying genetic polymorphism of Se-associated genes. This information may be helpful in dosage adjustment of Se supplementation for a population in order to get maximum benefits.

Selenium, diabetes, and their intricate sex-specific relationship

Selenium (Se) is an essential trace element, which is inserted as selenocysteine (Sec) into selenoproteins during biosynthesis, orchestrating their expression and activity. Se is associated with both beneficial and detrimental health effects; deficient supply or uncontrolled supplementation raises concerns. In particular, Se was associated with an increased incidence of type 2 diabetes (T2D) in a secondary analysis of a randomized controlled trial (RCT). In this review, we discuss the intricate relationship between Se and diabetes and the limitations of the available clinical and experimental studies. Recent evidence points to sexual dimorphism and an association of Se deficiency with gestational diabetes mellitus (GDM). We highlight the emerging evidence linking high Se status with improved prognosis in patients with T2D and lower risk of macrovascular complications.

Association of Blood Selenium Levels with Diabetes and Heart Failure in American General Adults: a Cross-sectional Study of NHANES 2011-2020 pre

Selenium is an essential trace element closely related to human health; however, the relationship between blood selenium levels, diabetes, and heart failure remains inconclusive. Therefore, this study aimed to explore the relationship between blood selenium levels and the prevalence of diabetes as well as heart failure in American general adults aged 20 years or older. This study utilized data from four survey cycles from NHANES 2011-2020 pre. Blood selenium levels were considered as both a continuous variable and quartiles, and logistic regression was employed to investigate the associations between blood selenium levels with diabetes and heart failure. Nonlinear relationships were examined by restricted cubic spline regression. The analysis included a total of 16311 participants aged 20 years or older. After adjustment for all potential confounder, we found when the blood selenium levels increased by 10 ug/L, the average risk of diabetes increased by 4.2% (95% CI: 1.5%, 7.0%), and the average risk of heart failure decreased by 5.0% (95% CI: 0.1%, 9.8%). In addition, compared with the lowest reference group, blood selenium levels were significantly positively associated with risk of diabetes in participants in the fourth quartile (OR=1.458, 95% CI: 1.173, 1.812), while significantly negatively associated with the risk of heart failure in participants in the second, third and fourth quartiles (Q2, OR=0.677, 95% CI: 0.471, 0.974) (Q3, OR=0.609, 95% CI: 0.426, 0.870) (Q4, OR=0.653, 95% CI: 0.443, 0.961). There was a nonlinear and reverse L-shaped association between blood selenium and diabetes, while a negative dose-response association between blood selenium and heart failure. Furthermore, the association between blood selenium levels and heart failure was more pronounced in participants with poor glycemic control, rather than diabetic patients. High blood selenium levels may be positively related to diabetes, while low blood selenium levels may be associated to heart failure. Appropriate blood selenium levels may help prevent diabetes and heart failure.

Sex-specific associations of serum selenium and selenoprotein P with type 2 diabetes mellitus and hypertension in the Berlin Aging Study II

BACKGROUND

Selenium is essential for expression and proper function of a set of redox active selenoproteins implicated in aging-relevant diseases, e.g. type 2 diabetes mellitus (T2D) and hypertension. However, data in cohorts of older adults, particularly with respect to different Se biomarkers and sex-specific analyses are sparse.

OBJECTIVE

To assess associations of serum Se and selenoprotein P (SELENOP) concentrations with T2D and hypertension in a cohort of older females and males.

METHODS

This study included 1500 participants from the Berlin Aging Study II. Diagnosis of T2D was made in case of antidiabetic medication, self-reported T2D, or laboratory parameters. Diagnosis of hypertension was based on self-report, blood pressure measurement, or anti-hypertensive medication. Se was measured by spectroscopy, and SELENOP by ELISA. Multiple adjusted regression models quantified dose-dependent associations.

RESULTS

Participants had a median(IQR) age of 68 (65,71) years, and 767 (51%) were women. 191 (13%) participants had T2D and 1126 (75%) had hypertension. Se and SELENOP correlated significantly (r = 0.59, p < 0.001), and were elevated in those with self-reported Se supplementation. Serum Se and SELENOP were not associated with T2D in the whole cohort. In men, SELENOP was positively associated with T2D, OR (95%CI) for one mg/L increase in SELENOP was 1.22 (1.00,1.48). Se was non-linearly associated with hypertension, comparing to the lowest quartile (Q1), and participants with higher Se levels (Q3) had a lower OR (95%CI) of 0.66 (0.45,0.96), which was specific for men. SELENOP positively associated with hypertension, and OR (95%CI) per one mg/L increase was 1.15 (1.01,1.32).

CONCLUSIONS

The data suggest a sex-specific interrelationship of Se status with T2D and hypertension, with apparent biomarker-specific associations.

Physiological Benefits of Novel Selenium Delivery via Nanoparticles

Dietary selenium (Se) intake within the physiological range is critical to maintain various biological functions, including antioxidant defence, redox homeostasis, growth, reproduction, immunity, and thyroid hormone production. Chemical forms of dietary Se are diverse, including organic Se (selenomethionine, selenocysteine, and selenium-methyl-selenocysteine) and inorganic Se (selenate and selenite). Previous studies have largely investigated and compared the health impacts of dietary Se on agricultural stock and humans, where dietary Se has shown various benefits, including enhanced growth performance, immune functions, and nutritional quality of meats, with reduced oxidative stress and inflammation, and finally enhanced thyroid health and fertility in humans. The emergence of nanoparticles presents a novel and innovative technology. Notably, Se in the form of nanoparticles (SeNPs) has lower toxicity, higher bioavailability, lower excretion in animals, and is linked to more powerful and superior biological activities (at a comparable Se dose) than traditional chemical forms of dietary Se. As a result, the development of tailored SeNPs for their use in intensive agriculture and as candidate for therapeutic drugs for human pathologies is now being actively explored. This review highlights the biological impacts of SeNPs on growth and reproductive performances, their role in modulating heat and oxidative stress and inflammation and the varying modes of synthesis of SeNPs.