Significant Beneficial Association of High Dietary Selenium Intake with Reduced Body Fat in the CODING Study

Understanding the Roles of Selenium on Thyroid Hormone-Induced Thermogenesis in Adipose Tissue

Brown adipose tissue (BAT) and white adipose tissue (WAT) are known to regulate lipid metabolism. A lower amount of BAT compared to WAT, along with adipose tissue dysfunction, can result in obesity. Studies have shown that selenium supplementation protects against adipocyte dysfunction, decreases WAT triglycerides, and increases BAT triiodothyronine (T3). In this review, we discuss the relationship between selenium and lipid metabolism regulation through selenoprotein deiodinases and the role of deiodinases and thyroid hormones in the induction of adipose tissue thermogenesis. Upon 22 studies included in our review, we found that studies investigating the relationship between selenium and deiodinases demonstrated that selenium supplementation affects the iodothyronine deiodinase 2 (DIO2) protein and the expression of its associated gene, DIO2, proportionally. However, its effect on DIO1 is inconsistent while its effect on DIO3 activity is not detected. Studies have shown that the activity of deiodinases especially DIO2 protein and DIO2 gene expression is increased along with other browning markers upon white adipose tissue browning induction. Studies showed that thermogenesis is stimulated by the thyroid hormone T3 as its activity is correlated to the expression of other thermogenesis markers. A proposed mechanism of thermogenesis induction in selenium supplementation is by autophagy control. However, more studies are needed to establish the role of T3 and autophagy in adipose tissue thermogenesis, especially, since some studies have shown that thermogenesis can function even when T3 activity is lacking and studies related to autophagy in adipose tissue thermogenesis have contradictory results.

Targeted Application of Functional Foods as Immune Fitness Boosters in the Defense against Viral Infection

In recent times, the emergence of viral infections, including the SARS-CoV-2 virus, the monkeypox virus, and, most recently, the Langya virus, has highlighted the devastating effects of viral infection on human life. There has been significant progress in the development of efficacious vaccines for the prevention and control of viruses; however, the high rates of viral mutation and transmission necessitate the need for novel methods of control, management, and prevention. In recent years, there has been a shift in public awareness on health and wellbeing, with consumers making significant dietary changes to improve their immunity and overall health. This rising health awareness is driving a global increase in the consumption of functional foods. This review delves into the benefits of functional foods as potential natural means to modulate the host immune system to enhance defense against viral infections. We provide an overview of the functional food market in Europe and discuss the benefits of enhancing immune fitness in high-risk groups, including the elderly, those with obesity, and people with underlying chronic conditions. We also discuss the immunomodulatory mechanisms of key functional foods, including dairy proteins and hydrolysates, plant-based functional foods, fermentates, and foods enriched with vitamin D, zinc, and selenium. Our findings reveal four key immunity boosting mechanisms by functional foods, including inhibition of viral proliferation and binding to host cells, modulation of the innate immune response in macrophages and dendritic cells, enhancement of specific immune responses in T cells and B cells, and promotion of the intestinal barrier function. Overall, this review demonstrates that diet-derived nutrients and functional foods show immense potential to boost viral immunity in high-risk individuals and can be an important approach to improving overall immune health.

Selenium as a Factor Moderating Depression and Obesity in Middle-Aged Women

The aim of this study was to evaluate the effect of serum selenium on PPAR-γ and the selected proinflammatory cytokines (IL-1β, IL-6, TNF-α) in relation to depressive symptoms and obesity in middle-aged women. The research procedure was as follows: a survey was performed using the authors’ questionnaire and the BDI, anthropometric measurements, and the analysis of blood for the levels of selenium, cytokines, and genetic analysis of the PPAR-γ polymorphism (n = 443). It was found that the BMI increased along with the concentration of IL-6. No moderating effect of selenium was observed, although the cut-off values for “p” were established for IL-β*Se (p = 0.068) and IL-6*Se (p = 0.068), so there was a potential association with these two markers. At high selenium levels, the effect of higher IL-β levels on a decrease in BMI was stronger, as was the effect of an increase in IL-6 levels on an increase in BMI. No effect of selenium on PPAR-γ was found in relation to depressive symptoms and obesity. Higher selenium levels may have a beneficial effect on BMI even at high IL-β concentrations, however, at high IL-6 concentrations, this effect was not observed. Selenium levels had no impact on depressive symptoms.

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.

Thermogenic Adipose Redox Mechanisms: Potential Targets for Metabolic Disease Therapies

Metabolic diseases, such as diabetes and non-alcoholic fatty liver disease (NAFLD), have several negative health outcomes on affected humans. Dysregulated energy metabolism is a key component underlying the pathophysiology of these conditions. Adipose tissue is a fundamental regulator of energy homeostasis that utilizes several redox reactions to carry out the metabolism. Brown and beige adipose tissues, in particular, perform highly oxidative reactions during non-shivering thermogenesis to dissipate energy as heat. The appropriate regulation of energy metabolism then requires coordinated antioxidant mechanisms to counterbalance the oxidation reactions. Indeed, non-shivering thermogenesis activation can cause striking changes in concentrations of both oxidants and antioxidants in order to adapt to various oxidative environments. Current therapeutic options for metabolic diseases either translate poorly from rodent models to humans (in part due to the challenges of creating a physiologically relevant rodent model) or tend to have numerous side effects, necessitating novel therapies. As increased brown adipose tissue activity results in enhanced energy expenditure and is associated with beneficial effects on metabolic health, such as decreased obesity, it has gathered great interest as a modulator of metabolic disease. One potential reason for the beneficial health effects may be that although non-shivering thermogenesis is enormously oxidative, it is also associated with decreased oxidant formation after its activation. However, targeting its redox mechanisms specifically to alter metabolic disease remains an underexplored area. Therefore, this review will discuss the role of adipose tissue in energy homeostasis, non-shivering thermogenesis in adults, and redox mechanisms that may serve as novel therapeutic targets of metabolic disease.

TetraSOD®, a Unique Marine Microalgae Ingredient, Promotes an Antioxidant and Anti-Inflammatory Status in a Metabolic Syndrome-Induced Model in Rats

Increased oxidative stress has been linked to the pathogenic process of obesity and can trigger inflammation, which is often linked with the risk factors that make up metabolic syndrome (MetS), including obesity, insulin resistance, dyslipidaemia and hypertension. TetraSOD^®, a natural marine vegan ingredient derived from the microalgae Tetraselmis chuii that is high in the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) has recently demonstrated in vitro increased activity of these key antioxidant enzymes. In the present study, the potential bioactive effects of three dietary dosages of TetraSOD^® in enhancing antioxidant and anti-inflammatory mechanisms to combat the metabolic disturbances that compose MetS were assessed in rats given a cafeteria (CAF) diet. Chronic supplementation with 0.17, 1.7, and 17 mg kg⁻¹ day⁻¹ of TetraSOD^® for 8 weeks ameliorated the abnormalities associated with MetS, including oxidative stress and inflammation, promoting endogenous antioxidant defence mechanisms in the liver (GPx and GSH), modulating oxidative stress and inflammatory markers in plasma (NOx, oxLDL and IL-10), and regulating genes involved in antioxidant, anti-inflammatory and immunomodulatory pathways in the liver, mesenteric white adipose tissue (MWAT), thymus, and spleen. Overall, TetraSOD^® appears to be a potential therapeutic option for the management of MetS.

Potential role of selenium in alleviating obesity-related iron dyshomeostasis

Obesity is a serious health problem in modern life and increases the risk of many comorbidities including iron dyshomeostasis. In contrast to malnourished anemia, obesity-related iron dyshomeostasis is mainly caused by excessive fat accumulation, inflammation, and disordered gut microbiota. In obesity, iron dyshomeostasis also induces disorders associated with gut microbiota, neurodegenerative injury, oxidative damage, and fat accumulation in the liver. Selenium deficiency is often accompanied by obesity or iron deficiency, and selenium supplementation has been shown to alleviate obesity and overcome iron deficiency. Selenium inhibits fat accumulation and exhibits anti-inflammatory activity. It regulates gut microbiota, prevents neurodegenerative injury, alleviates oxidative damage to the body, and ameliorates hepatic fat accumulation. These effects theoretically meet the requirements for the inhibition of factors underlying obesity-related iron dyshomeostasis. Selenium supplementation may have a potential role in the alleviation of obesity-related iron dyshomeostasis. This review verifies this hypothesis in theory. All the currently reported causes and results of obesity-related iron dyshomeostasis are reviewed comprehensively, together with the effects of selenium. The challenges and strategies of selenium supplementation are also discussed. The findings demonstrate the possibility of selenium-containing drugs or functional foods in alleviating obesity-related iron dyshomeostasis.

The Effects of Zinc and Selenium Supplementation on Body Composition and Thyroid Function in Individuals with Overweight or Obesity: A Systematic Review

People with obesity have been found to have lower zinc (Zn) and selenium (Se) circulatory levels and abnormal thyroid function than people with normal weight. Studies about the effects of Zn and Se supplementation on body composition and thyroid function of overweight-obese people showed inconsistent results. A systematic review of randomized controlled trials was conducted to determine the effects of Ζn supplementation, Se supplementation, and their combination on body composition and thyroid function of individuals with overweight or obesity. Databases of PubMed, ScienceDirect, and Cochrane, were searched from inception to February 27, 2022, to identify relevant articles. For the assessment of the methodological quality of the studies, the Jadad scale was used. After screening the articles, thirteen studies were finally included and were analyzed using the strength of the evidence approach. Regarding the effectiveness of Zn supplementation on body composition, moderate evidence was found, while the effects of Se were found to be mixed. Zn supplementation was found to affect the thyroid function of people with overweight or obesity by increasing their free triiodothyronine (FT3) levels. However, this result is based only on one study among hypothyroid patients. At this point, the effectiveness of Zn, Se, and their combination, on the body composition and the thyroid function of people with overweight or obesity cannot safely be determined because of the controversial results, small number, and the limitations of the identified studies. The results of this systematic review must be interpreted with caution due to the limitations detected.

High selenium levels associate with reduced risk of mortality and new-onset heart failure: data from PREVEND

Aim

To elucidate the relationship between serum selenium levels and the risk of mortality and new‐onset heart failure (HF) in the general adult population.

Methods and results

Selenium was measured in a Dutch cohort and a retrospective analysis of prospectively assessed data was performed. Main outcome measures were all‐cause mortality and incidence of new‐onset HF separately, and combined as a composite endpoint. Serum selenium was measured in 5973 subjects and mean selenium concentration was 84.6 (±19.5) µg/L. Mean age was 53.6 (±12.1) years and 3103 subjects (52%) were female. Median follow‐up was 8.4 years. Selenium levels associated positively with female sex, higher total cholesterol and glucose concentrations, and associated negatively with incidence of anaemia, iron deficiency, current smoking, increased C‐reactive protein levels, and higher body mass index. Univariate analysis on all subjects showed no association of continuous selenium concentrations, per 10 µg/L increase, with the composite endpoint (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.87–1.06, p = 0.407). However, significant interaction with smoking status was observed. In non‐smoking subjects (n = 4288), continuous selenium concentrations were independently associated with reduced mortality risk (HR 0.87, 95% CI 0.79–0.96, p = 0.005), lower risk of new‐onset HF (HR 0.82, 95% CI 0.69–0.96, p = 0.017), as well as reduced risk of the composite endpoint (HR 0.86, 95% CI 0.79–0.94, p = 0.001). In smoking subjects, no associations were found.

Conclusion

Serum selenium was independently associated with multiple indicators of the metabolic syndrome. In addition, high selenium levels were independently associated with reduced mortality and new‐onset HF in non‐smokers. Well‐powered interventional studies are necessary to evaluate the potential benefit of repleting selenium, especially in non‐smoking subjects.

Role for Selenium in Metabolic Homeostasis and Human Reproduction

Selenium (Se) is a micronutrient essential for life. Dietary intake of Se within the physiological range is critical for human health and reproductive functions. Selenium levels outside the recommended range have been implicated in infertility and variety of other human diseases. However, presently it is not clear how different dietary Se sources are processed in our bodies, and in which form or how much dietary Se is optimum to maintain metabolic homeostasis and boost reproductive health. This uncertainty leads to imprecision in published dietary guidelines and advice for human daily intake of Se and in some cases generating controversies and even adverse outcomes including mortality. The chief aim for this review is to describe the sources of organic and inorganic Se, the metabolic pathways of selenoproteins synthesis, and the critical role of selenprotenis in the thyroid gland homeostasis and reproductive/fertility functions. Controversies on the use of Se in clinical practice and future directions to address these challenges are also described and discussed herein.

Selenium Intake and Glycemic Control in Young Adults With Normal-Weight Obesity Syndrome

Numerous endogenous functions related to antioxidant processes, reproduction, and thyroid metabolism, as well as actions related to glycemic control, have been attributed to selenium. This study aimed to evaluate whether dietary selenium consumption is associated with variables of glycemic control in a sample of young Brazilian adults with Normal-Weight Obesity (NWO) syndrome. This was a cross-sectional study that evaluated 270 individuals with adequate body weight and excess body fat, who had their body composition assessed by dual-energy X-ray absorptiometry. Socioeconomic, health, and lifestyle questionnaires and three 24-h food records were applied. Glycemic control markers were also evaluated. The prevalence of inadequate selenium intake was analyzed by the Estimated Average Requirement (EAR) cut-point method. The prevalence of disturbances in glycemic control markers according to selenium consumption was compared by either the chi-square or the Fisher's exact test, with individuals classified according to the EAR values for selenium. The associations were evaluated by multiple linear regressions, using the backward strategy. The mean ± standard deviation (SD) age was 23.7 ± 3.3 years, and the mean ± SD daily selenium intake was 59.2 ± 26.4 μg. The overall prevalence of inadequate selenium intake was 59.2%. Individuals with selenium intakes below the EAR (≤45 μg/day) showed higher concentrations of glycated hemoglobin (HbA_1c) (P = 0.002) and a higher prevalence of disturbances in HbA_1c than those with selenium intakes above the EAR (>45 μg/day) (P = 0.001). Dietary selenium intake was directly associated with female sex (β = 19.95, 95% CI 5.00 to 34.89; P = 0.001) and weight (β = 6.69, 95% CI 0.56 to 12.81; P = 0.010), and inversely associated with the percentage of total body fat (β = -0.80, 95% CI -1.56 to -0,04; P = 0.010) and HbA_1c (β = -7.41, 95% CI -13.06 to -1.75; P = 0.010). Considering the noticeable young age of the individuals evaluated and the high frequency of disturbances in HbA_1c concentrations in those with selenium consumption below the recommendation, it is suggested that adequate dietary intake or supplementation of this micronutrient should be guaranteed to prevent future possible complications associated with glycemic control disturbances.

Association Between Selenium Intake with Chronic Constipation and Chronic Diarrhea in Adults: Findings from the National Health and Nutrition Examination Survey

The effects of dietary selenium intake on specific bowel habits (i.e., constipation or diarrhea) in the general population are not well understood. This study aims to evaluate the associations of selenium intake with the risk of chronic constipation and chronic diarrhea in adults aged ≥ 20 years using data from the 2007-2008 and 2009-2010 continuous National Health and Nutritional Examination Surveys (NHANES) (N = 9585). Chronic constipation and chronic diarrhea were defined by Bristol Stool Form Scale (BSFS) types 1 and 2 and BSFS types 6 and 7 as the "usual or most common stool type," respectively, and frequent laxative users were also defined as having chronic constipation. Dietary selenium intake was obtained from 24-h dietary recall. Multivariable logistic regression models were performed controlling for confounding factors (dietary, lifestyle, psychological, and health conditions). No significant associations between selenium intake and chronic diarrhea were found. However, selenium intake was inversely associated with the risk of chronic constipation. Compared with quartile 1, the multivariate-adjusted ORs (95% CI) of chronic constipation across quartiles 2 to 4 of selenium intake were 0.81 (0.64-1.03), 0.74 (0.58-0.95), and 0.54 (0.33-0.89), respectively. This association was significant among men, but not significant among women in subgroup analyses. Generally, there was an inverse association between selenium intake and chronic constipation in adults that modified by sex.

The neurotherapeutic role of a selenium-functionalized quinoline in hypothalamic obese rats

RATIONALE

Obesity is considered one of the major global health problems and increases the risk of several medical complications, such as diabetes and mental illnesses.

OBJECTIVE

The present study investigated the effect of 7-chloro-4-(phenylselanyl) quinoline (4-PSQ) on obesity parameters, behavioral and neurochemical alterations in hypothalamic obese rats.

METHODS

Male Wistar rats received subcutaneous neonatal injections of monosodium glutamate (MSG, 4g/kg) or saline. After the Lee Index evaluation, rats were divided into groups and treated with 4-PSQ (5 mg/kg, intragastric route) or canola oil once a day (post-natal days (PND) 60→76). Open-field, elevated plus-maze, forced swim task, object recognition/location memory, and stepdown inhibitory avoidance tasks were conducted from PND 66 to 74. On PND 76, rats were euthanized and epididymal fat, blood, cerebral cortex, andhippocampus were removed. Blood biochemical parameters and cortical/hippocampal acetylcholinesterase (AChE) and Na /K -ATPase activities were assessed.

RESULTS

MSG increased the Lee Index characterizing the chemically induced hypothalamic obesity model. 4-PSQ reversed the increases of epididymal fat, blood glucose, and triglyceride levels caused by MSG exposure. 4-PSQ attenuated anxiety-like and depression-like behaviors induced by neonatal administrations of MSG. Memory deficits found in MSG-obese rats were reversed by treatment with 4-PSQ. Neurochemical alterations produced by MSG evidenced by stimulation ofNa⁺/K⁺-ATPase and AChE activities in the cerebral cortex and hippocampus of rats were normalized by 4-PSQ treatment.

CONCLUSIONS

In brief, 4-PSQ therapy improved hypothalamic obesity-related parameters, as well as psychiatric symptoms, cognitive impairment, and neurochemical alterations found in obese rats.

Beneficial effects of Se/Zn co-supplementation on body weight and adipose tissue inflammation in high-fat diet-induced obese rats

This research investigated the effect of co-supplementation of selenium with zinc on weight control and the inflammatory and oxidative status in relation to obesity. Male Wistar rats (N = 32) were randomly divided into four groups after induction of obesity model: 1) "Zn" was supplemented with zinc sulfate (15 mg/kg BW), 2) "Se" supplemented with selenium as sodium selenate (0.5 mg/kg BW), 3) "Zn + Se" which received Zn (15 mg/kg BW) + Se (0.5 mg/kg BW), and 4) "HFD" as the control group. The intervention was done for eight weeks. At the end of treatment, serum and tissue level of Zn, Se, SOD, GSH-Px, MDA, leptin, TNF-α, and IL-6 was evaluated. Weight and food intake were significantly reduced in the Se group(p < .001), while in the Zn group, weight gain due to obesity was prevented compared to the control group (p = .48). There was a significant and stronger increase in SOD, GSH-Px levels and a remarkable decrease in MDA, leptin, TNF-α, and IL-6 in the group receiving the combination of two supplements than either alone(p < .001). Leptin had a positive correlation with inflammatory factors and lipid peroxidation marker and showed an inverse relationship with Zn and Se levels and anti-oxidative enzymes(p < .05). The analysis showed the mediating role of leptin in the effects of zinc. Co-supplementation of selenium and zinc may have a synergistic effect in reduction of oxidative and inflammatory markers. Regarding the effect of zinc on inflammatory factors and lipid peroxidation, leptin can play a mediating role.

[Effects of the intake of dairy products naturally enriched with selenium and omega-3 polyunsaturated fatty acids in a sample of postmenopausal women with metabolic syndrome: a randomized, triple-blind, placebo-controlled clinical trial]

INTRODUCTION

metabolic syndrome in postmenopausal women can improve with a healthy diet.

OBJECTIVES

to evaluate whether a dietary intervention with dairy products naturally enriched with selenium and omega-3 polyunsaturated fatty acids increases selenium plasma levels and improves cardiovascular risk factors in postmenopausal women with metabolic syndrome.

MATERIAL AND METHODS

a randomized, triple-blind, controlled clinical trial carried out in GP surgeries. Recruitment: April 2018, 46 postmenopausal women with metabolic syndrome who were frequent dairy consumers. Randomization: 23 in control group and 23 in experimental group.

INTERVENTION

consumption of dairy products naturally enriched with selenium and omega-3 polyunsaturated fatty acids (milk, yogurt, fresh cheese) for three months. Controls took conventional dairy. Primary endpoint: plasma selenium levels; secondary endpoints: metabolic syndrome criteria. Registration number 2018/256, Galicia Ethics Committee.

RESULTS

in all, 23 women in the control group and 21 in the intervention group completed the trial. Selenium increased in the intervention group (7.2 µg/L, 95 % CI, 3.7/10.8) compared to the control group (-4.5 µg/L, 95 % CI, -8/-1) (p < 0.001) and very low-density lipoprotein cholesterol decreased (-2.3 mg/dL, 95 % CI, -5.6/1) compared to the control group (1.9 mg/dL, 95 % CI, -0.7/4.5) (p = 0.043). Waist circumference (p = 0.010), body mass index (p = 0.047) and high-density lipoprotein cholesterol (p < 0.001) in the experimental group improved in comparison to baseline measurements.

CONCLUSIONS

an intervention with dairy products naturally enriched with selenium and omega-3 in a sample of postmenopausal women with metabolic syndrome can improve plasma selenium levels and very low-density lipoprotein cholesterol.

Exposure to a mixture of metals and growth indicators in 6-11-year-old children from the 2013-16 NHANES

Lead (Pb), mercury (Hg) and fluoride (F) exposure during childhood is of concern owing to their toxicity. Also, evidence suggests that high and low exposure levels to manganese (Mn) and selenium (Se) during this vulnerable period are associated with an increased risk of adverse health effects. A reduced growth is associated with high Pb and F exposure; however, little is known about their impact on children's body size, and there is a lack of consensus on the effects of Hg, Mn, and Se exposure on children's anthropometric measures. This is particularly true for childhood metal co-exposures at levels relevant to the general population. We investigated the joint effects of exposure to a metal mixture (Pb, Mn, Hg, and Se in blood and F in plasma) on 6-11-year-old US children's anthropometry (n = 1,634). Median F, Pb, Mn, Hg, and Se concentrations were 0.3 μmol/L, 0.5 μg/dL, 10.2 μg/L, 0.3 μg/L, and 178.0 μg/L, respectively. The joint effects of the five metals were modeled using Bayesian kernel machine and linear regressions. Pb and Mn showed opposite directions of associations with all outcome measured, where Pb was inversely associated with anthropometry. For body mass index and waist circumference, the effect estimates for Pb and Mn appeared stronger at high and low concentrations of the other metals of the mixture, respectively. Our findings suggest that metal co-exposures may influence children's body mass and linear growth indicators, and that such relations may differ by the exposure levels of the components of the metal mixture.

Regional Difference in the Association between the Trajectory of Selenium Intake and Hypertension: A 20-Year Cohort Study

The effect of selenium on hypertension is inconclusive. We aimed to study the relationship between selenium intake and incident hypertension. Adults (age ≥20 years) in the China Health and Nutrition Survey were followed up from 1991 to 2011 (N = 13,668). The latent class modeling method was used to identify trajectory groups of selenium intake. A total of 4039 respondents developed hypertension. The incidence of hypertension was 30.1, 30.5, 30.6, and 31.2 per 1000 person-years among participants with cumulative average selenium intake of 21.0 ± 5.1, 33.2 ± 2.8, 43.8 ± 3.6, and 68.3 ± 25.2 µg/day, respectively. Region and selenium intake interaction in relation to hypertension was significant. In the multivariable model, cumulative intake of selenium was only inversely associated with the incident hypertension in northern participants (low selenium zone), and not in southern participants. Compared to selenium intake trajectory Group 1 (stable low intake), all three trajectory groups had a low hazard ratio for hypertension among the northern participants. However, Group 4 (high intake and decreased) showed an increasing trend of hypertension risk in the south. In conclusion, the association between selenium intake and the incidence of hypertension varied according to regions in China. In the low soil selenium zone, high selenium intake might be beneficial for hypertension prevention.

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

Selenium in Endocrinology-Selenoprotein-Related Diseases, Population Studies, and Epidemiological Evidence

Selenium (Se), apart from iodine, iron, and calcium, is one of the nutrient-derived key elements strongly affecting the endocrine system. However, no specific hormonal "feedback" regulation for Se status has yet been identified, in contrast to the fine-tuned hormone network regulating Ca2+ and phosphate balance or hepcidin-related iron status. Since its discovery as an essential trace element, the effects of Se excess or deficiency on the endocrine system or components of the hypothalamic-pituitary-periphery feedback circuits, the thyroid hormone axis, glucoregulatory and adrenal hormones, male and female gonads, the musculoskeletal apparatus, and skin have been identified. Analysis of the Se status in the blood or via validated biomarkers such as the hepatically derived selenoprotein P provides valuable diagnostic insight and a rational basis for decision making on required therapeutic or preventive supplementation of risk groups or patients. Endocrine-related epidemiological and interventional evidence linking Se status to beneficial or potentially adverse actions of selected selenoproteins mediating most of the (patho-) physiological effects are discussed in this mini-review. Autoimmune thyroid disease, diabetes and obesity, male fertility, as well as osteoporosis are examples for which observational or interventional studies have indicated Se effects. The currently prevailing concept relating Se and selenoproteins to "oxidative stress," reactive oxygen species, radical hypotheses, and related strategies of pharmacological approaches based on various selenium compounds will not be the focus. The crucial biological function of several selenoproteins in cellular redox-regulation and specific enzyme reactions in endocrine pathways will be addressed and put in clinical perspective.

Reduced levels of plasma selenium are associated with increased inflammation and cardiovascular disease in an Italian elderly population

Selenium (Se) is an essential micronutrient for human health that protects from oxidative damage. Se deficiency has been associated with the development of cardiovascular diseases (CVD). In this study we aimed to investigate the association between Se status, CVD risk, cardio-metabolic and inflammatory markers in elderly population. Se Plasma levels and inflammatory markers [neutrophil/lymphocyte ratio, serum C-reactive protein (CRP) levels and Copper/Zinc ratio (Cu/Zn)] were measured in 858 control subjects (mean age 73.4 ± 9.3) and 606 CVD patients (mean age 72.5± 8.7). A multivariate logistic regression was performed to evaluate the association between Se deficiency (Se< 60 μg/L) and the risk of CDV. In a subgroup of 46 CVD patients the gene expression of IL-1β, CCL5/RANTES, IL-6, IL-8, IL-10, platelet-derived growth factor-β (PDGFβ) and sirtuins in peripheral blood mononuclear cell (PBMC) were further examined. Increased values of neutrophil/lymphocyte ratio, CRP levels and Cu/Zn ratio were observed in Se deficiency condition both in controls and in CVD patients. Moreover, enhanced gene expression of cytokines and chemokines such as IL1β, CCL5 and PDGF- β, and a downregulation of SIRT-1, SIRT-5, SIRT-6, SIRT-7 were found in PBMCs from CVD patients with Se deficiency. A multivariate logistic regression showed that Se deficiency was associated with an increased CVD risk (odds ratio=1.946, 95% CI: 1.19-3.18, p < 0.01). The current study revealed that Se deficiency is independently associated with CVD, and with elevated circulating inflammatory markers and affects the expression of cytokines, chemokines and sirtuins in PBMCs.

Micronutrient Status of Electronic Waste Recyclers at Agbogbloshie, Ghana

Growing evidence suggests that micronutrient status is adversely impacted by toxic metals (e.g., cadmium, lead, and arsenic) exposures; however, the micronutrient status of e-waste recyclers who are amongst the highest metal-exposed groups is not known. This study, therefore, assessed the micronutrient status of e-waste recyclers using dietary information (2-day 24-h recall survey) and biomarker data (whole blood and urine) among 151 participants (100 e-waste recyclers at Agbogbloshie and 51 controls at Madina Zongo from the Accra region, Ghana) in March 2017. Biomarker levels of iron (Fe), calcium (Ca), magnesium (Mg), selenium (Se), zinc (Zn) and copper (Cu) were analyzed by the ICP-MS. Linear regression models were used to assess associations ofwork-related factors and sociodemographic characteristics with micronutrient intake, blood, and urine micronutrient levels. The results showed that apart from Fe and Zn, e-waste recyclers at Agbogbloshie did not meet the day-to-day dietary requirements for Ca, Cu, Se, and Mg intake. Except for the low levels of Mg and Fe detected in blood of e-waste recyclers, all other micronutrients measured in both blood and urine of both groups fell within their reference range. Exposure to biomass burning was associated with lower blood levels of Fe, Mg, and Zn among the e-waste recyclers. Further, among e-waste recyclers, significant relationships were found between the number of years spent recycling e-waste and urinary Ca and Cu excretion. Given that, some dietary and blood levels of micronutrients were below their reference ranges, the implementation of evidence-based nutrition strategies remains necessary among e-waste recyclers to reduce their risk of becoming malnourished.

Relationships of Physical Activity and Diet Quality with Body Composition and Fat Distribution in US Adults

OBJECTIVE

This study aimed to investigate the relationships among physical activity (PA), diet quality, body composition, and fat distribution in a representative sample of US adults.

METHODS

A cross-sectional analysis was conducted using publicly accessible data from the 2011 to 2016 National Health and Nutrition Examination Survey and the Food Patterns Equivalents Database (n = 7,423). Variables from the data sets were analyzed for this study, including PA, two 24-hour dietary recalls, and dual-energy x-ray absorptiometry outputs.

RESULTS

For men, PA and diet quality were inversely associated with the percentage of body fat (β = -0.0042, 95% CI: -0.0084 to -0.0001; β = -0.28, 95% CI: -0.42 to -0.14) and fat mass index (β = -0.0125, 95% CI: -0.0209 to -0.0041; β = -0.56, 95% CI: -0.81 to -0.32); meeting the PA recommendation and having good diet quality provided an additive effect on body fat. A similar pattern was observed in women. Additionally, diet quality was inversely associated with all fat distribution measures in both sexes, whereas PA was positively associated with lean mass measures in men only.

CONCLUSIONS

Increased PA and/or better diet quality were associated with reduced body fat, a healthier fat distribution, and increased lean mass. Further research examining how changes in PA or diet quality influence body composition and fat distribution in adults is warranted.

Association between body mass index and estimated glomerular filtration rate in patients with chronic kidney disease of unknown aetiology in Sri Lanka

Chronic kidney disease of unknown aetiology (CKDu), which is widespread in the North Central Province (NCP) of Sri Lanka, is not associated with commonly known factors such as diabetes, hypertension, and glomerulonephritis. The pathogenicity of CKDu is not well understood, but people with a low body mass index (BMI) and mineral and nutrient deficiencies are more vulnerable to develop CKDu. To understand this situation, the relationship between BMI and the estimated glomerular filtration rate (eGFR) was investigated in people with CKDu in comparison with unaffected age-matched control groups in disease-endemic areas of the NCP. This community-based cross-sectional study was performed in Medirigiriya in the Polonnaruwa district of Sri Lanka, which has one of the highest densities of patients with CKDu. The data for identifying demographic factors and the relationship between CKDu and BMI were investigated by using a validated survey questionnaire. Findings indicated that the group with the highest number of people affected with CKDu (i.e. eGFR of less than 60 mL/min/1.73 m²) had the lowest BMI compared to those with normal eGFR. The majority affected were male farmers. The severity of the disease was inversely associated with BMI values and had a higher prevalence of smoking and alcohol consumption. In addition, those who consume water from household dug wells had significantly lower eGFR (p < 0.0001). A linear regression analysis revealed a significant positive association between lower eGFR and lower BMI (p < 0.001). We hypothesised that the low BMI in those with CKDu may have increased susceptibility to develop CKDu, in the presence of exposure to multiple nephrotoxins and adverse conditions.

Protective effects of selenium-enriched peptides from Cardamine violifolia against high-fat diet induced obesity and its associated metabolic disorders in mice

Selenium-enriched peptides from Cardamine violifolia (CSP) have excellent antioxidant functions but little is known about their effects on obesity and associated metabolic disorders in mice fed with a high-fat diet (HFD). In this study, C57BL/6 mice were fed a HFD with or without CSP supplementation (CSPL: 26 μg Se per kg bw per d; CSPH: 104 μg per kg bw per d) for 10 weeks. The results showed that both CSPL and CSPH could ameliorate overweight gain, excess fat accumulation, serum lipid metabolism, and insulin resistance. The potential mechanism might be associated with the increase in thermogenesis, reduced oxidative stress, and inflammation, which regulated the gene expression in lipid and cholesterol metabolism. In addition, CSPL and CSPH also maintained the intestinal integrity and modulated the gut microbiota. Increased Blautia in CSP may be involved in the protective effect against obesity. Furthermore, a distinct increase in Lactobacillus was exclusively found in CSPH, suggesting that a more effective function of CSPH on metabolic disorders might be through the synergism of Blautia and Lactobacillus. Spearman's correlation analysis revealed that these specific genera were significantly correlated with the metabolic improvements. Taken together, CSP supplementation prevented HFD-induced obesity and metabolic disorders, probably by ameliorating oxidative stress and inflammation, regulating metabolic genes, and modulating the gut microbiota compositions.

Low intakes of vitamins C and A are associated with obesity in early adulthood

To evaluate the relationships between the intake of individual antioxidants as well as the dietary antioxidant quality score and obesity-related measures. A cross-sectional study was conducted on 562 young adults. Fat mass, fat-mass percentage, and fat-free mass were measured using a body composition analyzer. The intake of antioxidant nutrients including vitamins C, E, and A, selenium, zinc, and magnesium were calculated based on a 72-hour diet recall interview. We observed significant differences in the vitamin C (88.6 ± 72.6 mg/day vs. 70.7 ± 60.6 mg/day, p = 0.010), vitamin A (635.8 ± 519.8 μg/day vs. 492.6 ± 318.9 μg/day, p = 0.014), and selenium (135.3 ± 88.7 μg/day vs. 139.3 ± 79.3 μg/day, p = 0.034) intake between normal-weight and overweight or obese young adults. When the Dietary Antioxidant Quality Score (DAQS) was analyzed, there were no significant differences between normal-weight versus overweight or obese young adults after adjusting for confounders. Logistic regression analysis revealed that vitamin C intake (odds ratio (OR) 0.995, 95% CI 0.992-0.999, p = 0.013) and vitamin A intake (OR 0.999, 95% CI 0.999-1.000, p = 0.016) were independent predictors of overweight/obesity after adjusting for age, sex and energy intake. In contrast, a higher selenium intake was associated with an increased risk of overweight/obesity (OR 1.003, 95% CI 1.000-1.006, p = 0.034). Future longitudinal investigations of dietary antioxidant intake in relation to the development of obesity would be of interest to better understand the effect of dietary antioxidants on obesity.

Facultative protein selenation regulates redox sensitivity, adipose tissue thermogenesis, and obesity

Oxidation of cysteine thiols by physiological reactive oxygen species (ROS) initiates thermogenesis in brown and beige adipose tissues. Cellular selenocysteines, where sulfur is replaced with selenium, exhibit enhanced reactivity with ROS. Despite their critical roles in physiology, methods for broad and direct detection of proteogenic selenocysteines are limited. Here we developed a mass spectrometric method to interrogate incorporation of selenium into proteins. Unexpectedly, this approach revealed facultative incorporation of selenium as selenocysteine or selenomethionine into proteins that lack canonical encoding for selenocysteine. Selenium was selectively incorporated into regulatory sites on key metabolic proteins, including as selenocysteine-replacing cysteine at position 253 in uncoupling protein 1 (UCP1). This facultative utilization of selenium was initiated by increasing cellular levels of organic, but not inorganic, forms of selenium. Remarkably, dietary selenium supplementation elevated facultative incorporation into UCP1, elevated energy expenditure through thermogenic adipose tissue, and protected against obesity. Together, these findings reveal the existence of facultative protein selenation, which correlates with impacts on thermogenic adipocyte function and presumably other biological processes as well.

Selenium and Selenoproteins in Adipose Tissue Physiology and Obesity

Selenium (Se) homeostasis is tightly related to carbohydrate and lipid metabolism, but its possible roles in obesity development and in adipocyte metabolism are unclear. The objective of the present study is to review the current data on Se status in obesity and to discuss the interference between Se and selenoprotein metabolism in adipocyte physiology and obesity pathogenesis. The overview and meta-analysis of the studies on blood Se and selenoprotein P (SELENOP) levels, as well as glutathione peroxidase (GPX) activity in obese subjects, have yielded heterogenous and even conflicting results. Laboratory studies demonstrate that Se may modulate preadipocyte proliferation and adipogenic differentiation, and also interfere with insulin signaling, and regulate lipolysis. Knockout models have demonstrated that the selenoprotein machinery, including endoplasmic reticulum-resident selenoproteins together with GPXs and thioredoxin reductases (TXNRDs), are tightly related to adipocyte development and functioning. In conclusion, Se and selenoproteins appear to play an essential role in adipose tissue physiology, although human data are inconsistent. Taken together, these findings do not support the utility of Se supplementation to prevent or alleviate obesity in humans. Further human and laboratory studies are required to elucidate associations between Se metabolism and obesity.

The other view: the trace element selenium as a micronutrient in thyroid disease, diabetes, and beyond

Antibiotics are provided for infections caused by bacteria, and statins help to control hypercholesterolemia. When hungry, you need to eat, and when you are deficient in a particular nutrient, the diet should be chosen wisely to provide what is missing. In the matter of providing the essential trace element selenium (Se), there are two different but partly overlapping views on its nature and requirements. Some consider it a medication that should be given to a subset of more or less well-defined (thyroid) patients only, in order to alleviate symptoms, to improve the course of the disease or even to provide a cure, alone or in an adjuvant mode. Such treatment attempts are conducted for a short time period, and potential medical benefits and side effects are evaluated thoroughly. One could also approach Se in medicine in a more holistic way and evaluate primarily the nutritional status of the patient before considering supplementation. The available evidence for positive health effects of supplemental Se can be interpreted as the consequence of correcting deficiency instead of speculating on a direct pharmaceutical action. This short review provides a novel view on Se in (thyroid) disease and beyond and offers an alternative explanation for its positive health effects, i.e., its provision of the substrate needed for allowing adequate endogenous expression of those selenoproteins that are required in certain conditions. In Se deficiency, the lack of the trace element constitutes the main limitation for the required adaptation of selenoprotein expression to counteract health risks and alleviate disease symptoms. Supplemental Se lifts this restriction and enables the full endogenous response of selenoprotein expression. However, since Se does not act as a pharmacological medication per se, it should not be viewed as a dangerous drug, and, importantly, current data show that supplemental Se does not cause diabetes.

Challenges and perspectives of selenium supplementation in Graves' disease and orbitopathy

PURPOSE

This review focuses on the results of prospective randomized clinical trials and the conclusions from respective meta-analyses in order to summarize experiences with adjuvant selenium (Se) supplementation in Graves' hyperthyroidism and orbitopathy, while identifying ambiguous findings and highlighting important open research issues.

METHODS

We searched the PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) through May 31, 2019, for relevant studies.

RESULTS

The available evidence concerning routine use of Se in the treatment of Graves' hyperthyroidism remains ambiguous. Results of meta-analyses, including ten RCTs, suggest that adjuvant Se supplementation can enhance the restoration of biochemical euthyroidism. Unfortunately, these results must be judged cautiously owing to several important limitations. Moreover, an in-depth analysis of relevant long-term clinical measures of therapeutic success (such as remission rate after antithyroid drug treatment), besides surrogate markers (for example, hormone or autoantibody concentrations), is generally missing. Based on a single study, Se supplementation is recommended in patients with mild orbitopathy of short duration because it may decrease inflammation and eye-specific symptoms while also achieving a marked improvement in disease-specific quality of life. The effects of Se supplementation on moderate-to-severe orbitopathy remain as yet unknown.

CONCLUSIONS

Additional randomized clinical trials with clinically relevant endpoints are urgently needed to further aid in clinical decision-making, including better stratification of Graves' disease patients, who are most likely to benefit from Se supplementation.

Selenium Supplementation, Body Mass Composition, and Leptin Levels in Patients with Obesity on a Balanced Mildly Hypocaloric Diet: A Pilot Study

BACKGROUND

Adequate levels of selenium (Se) have protective effects against several chronic diseases, such as obesity. The aim of this study was to assess the effect of Se supplementation in a selected group of patients with obesity.

METHODS

This randomized prospective study included 37 overweight/obese individuals aged 18-65 years, who adopted a slightly hypocaloric diet for 3 months. An intervention group received 240 μg/day of L-selenomethionine for 3 months; a control group received a placebo. Clinical and biochemical parameters, body composition measurements, and the Psychological General Well-Being Index (PGWBI) questionnaire were tested at the beginning and end of the treatment.

RESULTS

A comparison of the two groups showed a significant change in body composition, involving a decrease in body fat mass, between the baseline and the end of the follow-up, in the intervention group. Unlike the placebo group, the group given Se had a significant increase in lean body and muscle mass and a significant decrease in leptin levels after 3 months on diet. At the end of the follow-up, the group given Se scored higher on the PGWBI than those who did not.

CONCLUSION

Se could reinforce the effects of diet for overweight and obesity. This work was registered in the ISRCTN registry with study ID ISRCTN6106073.

Low serum choline and high serum betaine levels are associated with favorable components of metabolic syndrome in Newfoundland population

BACKGROUND

We investigated the relationships between serum choline and betaine levels with metabolic syndrome-related indices in the general population of Newfoundland.

METHODS

1081 adults were selected from the CODING study. Serum choline and betaine levels were measured. Major confounding factors were controlled in all analyses.

RESULTS

Partial correlation and linear regression analysis showed that serum choline levels were positively associated with systolic blood pressure (r: 0.124), serum TG levels (r: 0.132) and negatively correlated with serum glucose levels (r: -0.121) in males (p < 0.01 for all). In females, serum choline levels were positively correlated with serum TG, TC and HDL levels (r: 0.104 to 0.148, p < 0.05 for all). Serum betaine levels were negatively associated with serum TG, TC, LDL and insulin levels, and with atherogenic index and HOMA-IR index in males (r: -0.081 to -0.179, p < 0.05 for all). In females, serum betaine levels were negatively associated with serum TG, hsCRP and insulin levels, and with HOMA-IR index (r: -0.092 to -0.213, p < 0.05 for all). Moreover, subjects with serum choline levels in the highest tertile showed highest serum TG levels and systolic blood pressure in males, and highest serum lipids levels in females. Subjects with the highest serum betaine levels had the lowest serum lipids levels, atherogenic index, IR severity in males, and the lowest serum TG and hsCRP levels, and IR severity in females.

CONCLUSION

Low serum choline and high serum betaine levels are associated with favorable components of metabolic syndrome in general adults.

Dietary Intake of Selenium in Relation to Pubertal Development in Mexican Children

Alterations in pubertal timing have been associated with long-term health outcomes. While a few reports have shown that dietary intake of selenium is associated with fertility and testosterone levels in men, no human studies have considered the association between selenium and pubertal development in children. We examined the cross-sectional association of childhood dietary intake of selenium with pubertal development among 274 girls and 245 boys aged 10–18 years in Mexico City. Multiple logistic and ordinal regression models were used to capture the association between energy-adjusted selenium intake (below Recommended Dietary Allowance (RDA) vs. above RDA) and stages of sexual maturity in children, adjusted for covariates. We found that boys with consumption of selenium below the RDA had lower odds of a higher stage for pubic hair growth (odds ratio (OR) = 0.51, 95% confidence interval (95% CI): 0.27–0.97) and genital development (OR = 0.53, 95% CI: 0.28–0.99) as well as a lower probability of having matured testicular volume (OR = 0.37, 95% CI: 0.15–0.88) compared with boys who had adequate daily dietary intake of selenium (above RDA). No associations were found in girls. According to our results, it is possible that inadequate consumption of selenium may be associated with later pubertal development in boys, suggesting a sex-specific pattern. Future work with a larger sample size and measures of selenium biomarkers is needed to confirm our findings and improve understanding of the role of this mineral in children’s sexual development.

Inverse association of long-term nut consumption with weight gain and risk of overweight/obesity: a systematic review

Nuts contain a variety of nutrients and bioactive compounds that are capable of promoting metabolic health. However, due to their high energy density, concerns have been raised that nut consumption in the long term may contribute to weight gain. This systematic review summarizes the findings of prospective studies regarding the relationship between long-term nut consumption and obesity. Searches were conducted up through February 2018, using the PUBMED, EMBASE, and SCOPUS databases with the relevant MeSH terms and phrases. This systematic review included prospective cohort studies investigating the relationship between consumption of total nut and/or nut subtypes with changes in weight, body mass index (BMI), and waist circumference (WC), as well as the risk of overweight/obesity, with follow-up duration ≥1-year. Out of a total of 1580 papers that were initially examined, 6 met the inclusion criteria. Four out of the 6 studies showed an inverse association between nut consumption (typically at the dosages of ≥1 to 2 servings per week) and weight gain and risk of overweight/obesity. The remaining 2 studies evaluated the association between nut intake and changes in WC. From these 2 studies, only one study reported a significant inverse association. Overall, evidence from limited cohort studies demonstrated that long-term nut intake was associated with less weight gain and reduced risk of overweight/obesity. Whether such findings are generalizable to racially diverse ethnic groups, individuals of low socioeconomic status, and populations in developing countries should be addressed in future studies.

Unfavorable Associations Between Serum Trimethylamine N-Oxide and L-Carnitine Levels With Components of Metabolic Syndrome in the Newfoundland Population

Background: We aimed to study the relationships between serum Trimethylamine N-oxide (TMAO) and L-carnitine levels with metabolic syndrome profiles, including obesity, blood pressure, serum lipids, serum glucose and insulin resistance (IR)-related index in humans. Methods: Cross-sectional study was performed in 1,081 subjects from the CODING study in Newfoundland. Serum TMAO and L-carnitine levels were quantified by LC-MS/MS. Metabolic markers were measured in all subjects using fasting blood samples. Partial correlation and linear regression analysis were employed after systematically controlling the major confounding factors, such as age, gender, calorie intake and physical activity level. Results: Serum L-carnitine level was positively correlated with serum triglyceride (TG), serum insulin, IR in males with normal fasting glucose (p < 0.05 for all) and positively correlated with only serum TG (p < 0.05) in those with hyperglycemia. In females, significant positive correlations were identified between serum L-carnitine level with obesity, serum total cholesterol, glucose, insulin, and IR in those with normal fasting glucose level (p < 0.05 for all), while none was found in those with hyperglycemia. Serum TMAO level was only identified to be positively correlated with serum insulin level and IR in hyperglycemic males (p < 0.05 for all). Conclusions: Serum L-carnitine level was significantly associated with an unfavorable metabolic syndrome (MS) profile mainly in subjects with normal serum glucose level, while serum TMAO level was associated with an unfavorable MS profile in subjects with hyperglycemia. The gender difference warrants further investigations.

Higher serum choline and betaine levels are associated with better body composition in male but not female population

Background

Animal studies proved that choline and betaine have beneficial effect on reducing body fat. However, evidence in humans is scarce. We aim to investigate the association between serum choline and betaine levels with body composition in general population.

Methods

This is an observational cross-sectional study performed in 1081 subjects from the CODING (Complex Disease in Newfoundland population: Environment and Genetics) study. Serum choline and betaine levels were measured based on liquid chromatography coupled with tandem mass spectrometry technology. Body composition was measured using dual-energy X-ray absorptiometry following a 12-hour fast. Major confounding factors including age, sex, total calorie intake and physical activity level were controlled in all analyses.

Results

Significantly inverse correlations were found between serum betaine levels and all obesity measurements in males (r ranged from -0.12 to -0.23, and p<0.01 for all) but not in females. Serum choline was negatively associated with total percent body fat (%BF), percent trunk fat (%TF), weight, body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (r ranged from -0.11 to -0.19, and p<0.05 for all) in males and positively associated with weight, BMI and WC (r ranged from 0.09 to 0.10, and p<0.05 for all) in females. The negative associations between serum choline and betaine levels with obesity in males were more profound in those not on any medication than those taking medications. Moreover, obese males had the lowest serum choline and betaine levels, followed by overweight males, and normal weight males having the highest serum choline and betaine levels, especially in those not taking medications (p<0.05). Likewise, subjects with the highest serum levels of both had the lowest obesity indexes, especially those not taking medications.

Conclusions

Higher serum choline and betaine levels were associated with a more favorable body composition (lower body fat and higher lean body mass) in males and the favorable association was more pronounced in non-medication users.

Hypothalamic pathways regulate the anorectic action of p-chloro-diphenyl diselenide in rats

Behavioral studies have suggested that (p-ClPhSe)₂ elicits an anorectic-like action in rats by inducing multiple effects such as satiety-enhancing effect, malaise and specific flavor; however, the molecular mechanisms underlying its anorexigenic action remain unclarified. Here, male Sprague-Dawley rats received acute and sub-chronic intraperitoneal treatments with (p-ClPhSe)₂; thereafter, in vivo and ex vivo analyses were carried out. The present study reveals that the reduction of food intake resulting from a single treatment with (p-ClPhSe)₂ (1mg/kg, i.p.) was associated with decreased hypothalamic levels of pro-melanin-concentrating hormone (pro-MCH) and orexin precursor. In addition, repeated administrations of (p-ClPhSe)₂ (10mg/kg; i.p.) for 7 days induced sustained food intake suppression, body weight loss and white fat reduction. Measurements of brown adipose tissue content and temperature as well as data obtained from a pair-fed group indicated that the effects of (p-ClPhSe)₂ on the body weight are closely related to its anorexigenic actions, ruling out the possibility of increased thermogenesis. Furthermore, (p-ClPhSe)₂ reduced the hypothalamic orexin precursor levels when repeatedly administered to rats. Sub-chronic treatment with (p-ClPhSe)₂ caused a decrease of serum triglyceride levels and down-regulation of hepatic cholesterol content. Therefore, the current study characterized the anorectic and reducing body weight actions of (p-ClPhSe)₂ in Sprague-Dawley rats. Besides, the set of results suggests that food intake suppressant effects triggered after (p-ClPhSe)₂ administration to rats are mainly related with the lower orexin levels in hypothalamus after acute and sub-chronic treatments.

High dietary selenium intake is associated with less insulin resistance in the Newfoundland population

As an essential nutrient, Selenium (Se) is involved in many metabolic activities including mimicking insulin function. Data on Se in various biological samples and insulin resistance are contradictory, moreover there is no large study available regarding the relationship of dietary Se intake with insulin resistance in the general population. To investigate the association between dietary Se intake and variation of insulin resistance in a large population based study, a total of 2420 subjects without diabetes from the CODING (Complex Diseases in the Newfoundland Population: Environment and Genetics) study were assessed. Dietary Se intake was evaluated from the Willett Food Frequency questionnaire. Fasting blood samples were used for the measurement of glucose and insulin. Insulin resistance was determined with the homeostasis model assessment (HOMA-IR). Body composition was measured using dual energy X-ray absorptiometry. Analysis of covariance showed that high HOMA-IR groups in both males and females had the lowest dietary Se intake (μg/kg/day) (p < 0.01), being 18% and 11% lower than low HOMA-IR groups respectively. Insulin resistance decreased with the increase of dietary Se intake in females but not in males after controlling for age, total calorie intake, physical activity level, serum calcium, serum magnesium, and body fat percentage (p < 0.01). Partial correlation analysis showed that dietary Se intake was negatively correlated with HOMA-IR after adjusting for the Se confounding factors in subjects whose dietary Se intake was below 1.6 μg/kg/day (r = -0.121 for males and -0.153 for females, p < 0.05). However, the negative correlation was no longer significant when dietary Se intake was above 1.6 μg/kg/day. Our findings suggest that higher dietary Se intake is beneficially correlated with lower insulin resistance when total dietary Se intake was below 1.6 μg/kg/day. Above this cutoff, this beneficial effect disappears.

Selenium Status in Patients with Turner Syndrome: a Biochemical Assessment Related with Body Composition

Studies about selenium status in patients with Turner syndrome (TS) are non-existent in the literature. The aim of this study was to evaluate selenium status in patients with TS, while considering the different ages of the studied population and the relation with body composition. In total, 33 patients with TS were evaluated and grouped according to their developmental stages (children, adolescents, and adults). Selenium concentrations in their plasma, erythrocytes, urine, and nails were determined by using hydride generation atomic absorption spectrometry and erythrocyte glutathione peroxidase activity were measured by using Randox commercial kits. Additionally, height, weight, body fat percentage, waist circumference, and waist-height ratio were measured to characterize the patients. No differences in the selenium concentrations in the plasma, erythrocyte, urine, and nails or in the glutathione peroxidase activity were observed among the age groups (p > 0.05). The evaluated selenium levels were less than the established normal ones. The patients with larger waist circumference, body fat percentage, body mass index, and waist-height ratio showed lower glutathione peroxidase enzyme activity (p = 0.023). The present study shows that most patients with TS are deficient in selenium and that those with a greater accumulation of body fat have a lower GPx activity.

Dietary Selenium and Human Health

Next year (2017), the micronutrient Selenium (Se) is celebrating its birthday—i.e., 200 years after first being identified by the Swedish chemist Jöns Jakob Berzelius. Despite its impressive age, research into the functions of this essential trace element is very alive and reaching out for new horizons. This special issue presents some recent fascinating, exciting, and promising developments in Se research in the form of eight original contributions and seven review articles. Collectively, aspects of Se supply, biochemical, physiological, and chemotherapeutic effects, and geobiological interactions are covered by leading scientists in the areas of nutritional, basic, and clinical research. It is obvious from the contributions that the bicentennial anniversary will celebrate a micronutrient still in its infancy with respect to being understood in terms of its biomedical importance.