Selenium⁻Fascinating Microelement, Properties and Sources in Food

Seleno-Metabolites and Their Precursors: A New Dawn for Several Illnesses?

Selenium (Se) is an essential element for human health as it is involved in different physiological functions. Moreover, a great number of Se compounds can be considered potential agents in the prevention and treatment of some diseases. It is widely recognized that Se activity is related to multiple factors, such as its chemical form, dose, and its metabolism. The understanding of its complex biochemistry is necessary as it has been demonstrated that the metabolites of the Se molecules used to be the ones that exert the biological activity. Therefore, the aim of this review is to summarize the recent information about its most remarkable metabolites of acknowledged biological effects: hydrogen selenide (HSe-/H2Se) and methylselenol (CH3SeH). In addition, special attention is paid to the main seleno-containing precursors of these derivatives and their role in different pathologies.

Molecular mechanisms and therapeutic effects of different vitamins and minerals in COVID-19 patients

COVID-19 is a rapidly spreading disease, which has caught the world by surprise. Millions of people suffer from illness, and the mortality rates are dramatically high. Currently, there is no specific and immediate treatment for this disease. Remedies are limited to supportive regiments and few antiviral and anti-inflammatory drugs. The lack of a definite cure for COVID-19 is the reason behind its high mortality and global prevalence. COVID-19 can lead to a critical illness with severe respiratory distress and cytokine release. Increased oxidative stress and excessive production of inflammatory cytokines are vital components of severe COVID-19. Micronutrients, metalloids, and vitamins such as iron, manganese, selenium, Zinc, Copper, vitamin A, B family, and C are among the essential and trace elements that play a pivotal role in human nutrition and health. They participate in metabolic processes that lead to energy production. In addition, they support immune functions and act as antioxidants. Therefore, maintaining an optimal level of micronutrients intake, particularly those with antioxidant activities, is essential to fight against oxidative stress, modulate inflammation, and boost the immune system. Therefore, these factors could play a crucial role in COVID-19 prevention and treatment. In this review, we aimed to summarize antiviral properties of different vitamins and minerals. Moreover, we will investigate the correlation between them and their effects in COVID-19 patients.

Selenium and mercury concentrations in biological samples from patients with COVID-19

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a systemic disease affecting multiple organs. Furthermore, viral infection depletes several trace elements and promotes complex biochemical reactions in the body. Smoking has been linked to the incidence of COVID-19 and associated mortality, and it may impact clinical effects, viral and bacterial conversion, and treatment outcomes.

OBJECTIVES

To study the relationship between severe acute respiratory syndrome coronavirus type 2 and the elemental concentrations of selenium (Se) and mercury (Hg) in biological samples from smokers and nonsmokers infected with the virus and in healthy individuals.

METHOD

We evaluated changes in the concentrations of essential (Se) and toxic (Hg) elements in biological samples (blood, nasal fluid, saliva, sputum, serum, and scalp hair) collected from male smokers and nonsmokers (aged 29-59 years) infected with COVID-19 and from healthy men in the same age group. The patients lived in different cities in Sindh Province, Pakistan. The Se and Hg concentrations were determined using atomic absorption spectrophotometry.

RESULTS

Se concentrations in all types of biological samples from smokers and nonsmokers with COVID-19 were lower than those of healthy smokers and nonsmokers. Hg concentrations were elevated in both smokers and nonsmokers with COVID-19.

CONCLUSIONS

In the current study, persons infected with COVID-19 had higher concentrations of toxic Hg, which could cause physiological disorders, and low concentrations of essential Se, which can also cause weakness. COVID-19 infection showed positive correlations with levels of mercury and selenium. Thus, additional clinical and experimental investigations are essential.

A comparative study of electrocoagulation treatment with iron, aluminum and zinc electrodes for selenium removal from flour production wastewater

Electrocoagulation (EC) using iron (Fe), zinc (Zn) and aluminum (Al) electrodes was comparatively applied in the treatment of selenium (Se) in flour production (FP) wastewater. It was indicated that EC treatment with Fe anode obtained highest removal efficiency (79.1%) for Se in the 90 min treatment in the comparative study, which could be attributed to the superior adsorption capacity of in-situ generated iron flocs. Removal of Se resulted from electrodeposition and adsorption to in-situ generated flocs in EC treatment, and the operational conditions significantly influenced the Se removal performance in this work. The results showed the acidic condition and higher current density favored EC treatment on Se removal, EC removed up to 97.8% of Se at pH 4 under 15 mA cm^-2, whereas it obtained 83.5% and 50.4% of removal efficiency at pH 7 and 10, respectively. There was competitive adsorption in the process of selenium removal, as the in-situ generated flocs effectively removed 35.6% of humic acid-like (HA-like) substance in FP wastewater after 90 min treatment. The FTIR results showed that HA-like substance mainly contained the protein water hydrogen bond, carboxylate COO antisymmetric stretching and other functional groups. Through the analysis of existence of Se in flocs and wastewater, it can be found that approximately 2.8%-3.92% of Se was removed by electrodeposition process. This study illustrated the Se removal mechanism and provided constructive suggestion for food manufacturing to the metal removal and utilization of advanced treatment.

COVID-19 and Selenium Deficiency: a Systematic Review

Several studies have indicated that selenium deficiency may be detrimental in the context of various viral disorders, and in the case of COVID-19, several studies have reported heterogeneous results concerning the association of selenium deficiency with the severity of disease. To summarize the available data surrounding the association of body selenium levels with the outcomes of COVID-19, a systematic search was performed in the Medline database (PubMed), Scopus, Cochrane Library, Embase, and Web of Science using keywords including "SARS-CoV-2," "COVID-19," and "selenium," Studies evaluating the association of COVID-19 with body selenium levels were included. Among 1,862 articles viewed in the database search, 10 articles were included after title, abstract, and full-text review. One study was further included after searching the literature again for any newly published articles. Out of 11 included studies, 10 studies measured serum selenium level, and one study investigated urinary selenium level. Three of 10 studies measured serum SELENOP level as well as selenium level. Glutathione peroxidase-3 level in serum was also assessed in one study. The reported outcomes were severity, mortality, and risk of COVID-19. Nine studies indicated that a lower serum selenium level is associated with worse outcomes. Two studies reported no significant association between serum selenium level and COVID-19. In one study, urinary selenium level was reported to be higher in severe and fatal cases compared to non-severe and recovered patients, respectively. In most cases, selenium deficiency was associated with worse outcomes, and selenium levels in COVID-19 patients were lower than in healthy individuals. Thus, it could be concluded that cautious selenium supplementation in COVID-19 patients may be helpful to prevent disease progression. However, randomized clinical trials are needed to confirm this.

Foliar selenium fertilization alters the content of dietary phytochemicals in two rocket species

Biofortification is the process that aims to enrich crops in micronutrients and valuable compounds. Selenium (Se) biofortification has particularly attracted increasing interest in recent times due to the growing number of individuals suffering from Se deficiency. Selenate and selenite are the Se forms most frequently administered to crops. In this study, Se was applied foliarly as selenate at 2.5, 5, or 10 mg per plant to two rocket species, Diplotaxis tenuifolia and Eruca sativa, grown in soil and the effects in terms of Se enrichment and content of primary and secondary metabolites were comparatively analyzed. We also compared our results with those obtained previously when selenate was supplied to the same species in hydroponics by addition to the nutrient solution. In most cases, the results were the opposite. In E. sativa, foliar Se treatment was more effective in promoting Se accumulation, sulfur (S), cysteine, and glucosinolates. No significant effect of Se was evident on total phenolic content, but there were individual phenols. Among amino acids, the content of proline was increased by Se, perhaps to counteract osmotic stress due to high Se accumulation. In D. tenuifolia, the content of S and cysteine decreased under Se treatment, but the amount of glutathione was steady, suggesting a preferred assimilation of cysteine toward the synthesis of this antioxidant. Consistent, the content of methionine and glucosinolates was reduced. The content of total phenolics was enhanced only by the low Se dosage. In both species, selenocysteine (SeCys) was identified, the content of which was higher compared to plants grown hydroponically. Concluding, most metabolic differences between rocket species were observed at high Se supplementation. Low Se foliar fertilization was effective in an enriching rocket in Se without affecting other phytochemicals. However, the Se dosages sufficient for biofortification could be even lower, as the Se concentration in rocket treated with 2.5 mg Se per plant was still very high and the edible part should not be eaten undiluted. Also, a single method of Se supplementation does not appear to be optimal for all plant species or the same species, as the metabolic responses could be very different.

Effects of exogenous selenium application on nutritional quality and metabolomic characteristics of mung bean (Vigna radiata L.)

Selenium (Se) biofortification is an important strategy for reducing hidden hunger by increasing the nutritional quality of crops. However, there is limited metabolomic information on the nutritional quality of Se-enriched mung beans. In this study, physiological assays and LC-MS/MS based widely targeted metabolomics approach was employed to reveal the Se biofortification potential of mung bean by evaluating the effect of Se on mung bean nutraceutical compounds and their qualitative parameters. Physiological data showed that foliar application of 30 g ha^-1 Se at key growth stages significantly increased the content of Se, protein, fat, total phenols, and total flavonoids content in two mung bean varieties. Widely targeted metabolomics identified 1,080 metabolites, among which L-Alanyl-L-leucine, 9,10-Dihydroxy-12,13-epoxyoctadecanoic acid, and 1-caffeoylquinic acid could serve as biomarkers for identifying highly nutritious mung bean varieties. Pathway enrichment analysis revealed that the metabolic pathways of different metabolites were different in the Se-enriched mung bean. Specifically, P1 was mainly enriched in the linoleic acid metabolic pathway, while P2 was mainly enriched in the phosphonate and phosphinate metabolic pathways. Overall, these results revealed the specific Se enrichment mechanism of different mung bean varieties. This study provides new insights into the comprehensive improvement of the nutritional quality of mung beans.

Enrichment characteristics and dietary evaluation of selenium in navel orange fruit from the largest navel orange-producing area in China (southern Jiangxi)

Diet is the main intake source of selenium (Se) in the body. Southern Jiangxi is the largest navel orange-producing area in China, and 25.98% of its arable land is Se-rich. However, studies on the Se-rich characteristics and Se dietary evaluation of navel orange fruits in the natural environment of southern Jiangxi have not been reported. This study was large-scale and in situ samplings (n = 492) of navel oranges in southern Jiangxi with the goal of investigating the coupling relationships among Se, nutritional elements, and quality indicators in fruits and systematically evaluating Se dietary nutrition to the body. The results indicated that the average content of total Se in the flesh was 4.92 μg⋅kg^-1, and the percentage of Se-rich navel oranges (total Se ≥ 10 μg⋅kg^-1 in the flesh) was 7.93%, of which 66.74% of the total Se was distributed in the pericarp and 33.26% in the flesh. The average content of total Se in the flesh of Yudu County was the highest at 5.71 μg⋅kg^-1. There was a significant negative correlation (p < 0.05) between Se, Cu, and Zn in the Se-rich flesh. According to the Se content in the flesh, the Se dietary nutrition evaluation was carried out, and it was found that the Se-enriched navel orange provided a stronger Se nutritional potential for the human body. These findings will help to identify Se enrichment in navel orange fruit in China's largest navel orange-producing area and guide the selection of Se-rich soils for navel orange production in the future.

Dregs of Cardamine hupingshanensis as a feed additive to improve the egg quality

Natural plant herbs have many active compounds to prevent poultry diseases and improve poultry products. However, most herbs are supplied for human medicine. Thus, for economic and sustainable development purposes, the dregs of Cardamine hupingshanensis (DCH) were developed as a feed additive to improve the egg quality of laying hens in this work. Results showed that the contents of selenium in hen serum and eggs were increased under DCH feeding. Subsequently, DCH also promotes the antioxidant capacity and immunity of laying hens through the increase of superoxide dismutase (SOD), catalase (CAT), and immunoglobulin G (IgG) by ELISA detection. Finally, production performance and egg quality were further graded by monitoring the product condition and scoring the indexes of egg quality, which also displayed that DCH as a feed additive significantly improved the egg quality by enhancing yolk color, eggshell thickness, and egg shape index.

Immunomodulatory roles of selenium nanoparticles: Novel arts for potential immunotherapy strategy development

Current chemotherapy strategies used in clinic appear with lots of disadvantages due to the low targeting effects of drugs and strong side effects, which significantly restricts the drug potency, causes multiple dysfunctions in the body, and even drives the emergence of diseases. Immunotherapy has been proved to boost the body’s innate and adaptive defenses for more effective disease control and treatment. As a trace element, selenium plays vital roles in human health by regulating the antioxidant defense, enzyme activity, and immune response through various specific pathways. Profiting from novel nanotechnology, selenium nanoparticles have been widely developed to reveal great potential in anticancer, antibacterial, and anti-inflammation treatments. More interestingly, increasing evidence has also shown that functional selenium nanoparticles can be applied for potential immunotherapy, which would achieve more effective treatment efficiency as adjunctive therapy strategies for the current chemotherapy. By directly interacting with innate immune cells, such as macrophages, dendritic cells, and natural killer cells, selenium nanoparticles can regulate innate immunity to intervene disease developments, which were reported to boost the anticancer, anti-infection, and anti-inflammation treatments. Moreover, selenium nanoparticles can also activate and recover different T cells for adaptive immunity regulations to enhance their cytotoxic to combat cancer cells, indicating the potential of selenium nanoparticles for potential immunotherapy strategy development. Here, aiming to enhance our understanding of the potential immunotherapy strategy development based on Se NPs, this review will summarize the immunological regulation effects of selenium nanoparticles and the application of selenium nanoparticle-based immunotherapy strategies. Furthermore, we will discuss the advancing perspective of selenium nanoparticle-based potential immunotherapy as a kind of novel adjunctive therapy to enhance the efficiency of current chemotherapies and also introduce the current obstacles for the development of selenium nanoparticles for potential immunotherapy strategy development. This work is expected to promote the future research on selenium nanoparticle-assisted immunotherapy and finally benefit the more effective disease treatments against the threatening cancer and infectious and chronic diseases.

Selenium as an important factor in various disease states - a review

Selenium (Se) is an element that has a pro-health effect on humans and animals. However, both the deficiency of this element and its excess may prove harmful to the body depending on the chemical form of the selenium, the duration of supplementation, and the human health condition. Many data indicate insufficient coverage of the demand for selenium in humans and animals due to its low content in soils and food products. A balance in the physiological process of the body can be achieved via the proper percentage of organically active minerals in the feed of animals as well as human beings. Selenium is a trace mineral of great importance to the body, required for the maintenance of a variety of its processes; primarily, selenium maintains immune endocrine, metabolic, and cellular homeostasis. Recently, this element has been emerging as a most promising treatment option for various disorders. Therefore, research based on Se has been increasing in recent times. The present review is designed to provide up-to-date information related to Se and its different forms as well as its effects on health.

Selenium regulates the mitogen-activated protein kinase pathway to protect broilers from hexavalent chromium-induced kidney dysfunction and apoptosis

Hexavalent chromium [Cr (VI)] is a common environmental pollutant. Although selenium (Se) can antagonize the toxicity of Cr (VI), the specific underlying mechanism has not been identified. To investigate this mechanism, we used potassium dichromate (K₂Cr₂O₇) and selenium-rich yeast (SeY) to construct single Cr (VI)- and combined Se/Cr (VI)-exposed broiler models during a 42-day period. Broilers were randomly assigned to the control (C), SeY (Se), SeY + Cr (VI) (Se/Cr), and Cr (VI) (Cr) groups. The antagonistic mechanisms of Se and Cr (VI) were evaluated using histopathological evaluation, serum and tissue biochemical tests, real-time fluorescence quantitative polymerase chain reaction, and western blotting. The results suggested that Se alleviated the morphological and structural damage to renal tubules and glomeruli, while reducing the organ index, creatinine levels, and blood urea nitrogen levels in the kidneys of Cr (VI)-exposed broilers. Furthermore, Cr (VI) reduced the levels of superoxide dismutase and glutathione, and increased the levels of malondialdehyde, in broiler kidney tissues. However, Se alleviated Cr (VI)-induced oxidative stress by increasing the levels of superoxide dismutase and glutathione, and decreasing the levels of malondialdehyde, within a certain range. Compared to the C group, the levels of p38, JNK, p-p38, p-JNK, p-p38/p38, and p-JNK/JNK significantly increased, whereas those of ERK, p-ERK, and p-ERK/ERK decreased, in the Cr group. Compared to the Cr group, the levels of p38, JNK, p-p38, p-JNK, p-p38/p38, and p-JNK/JNK significantly decreased, whereas those of ERK, p-ERK, and p-ERK/ERK increased, in the Se/Cr group. Furthermore, the levels of p53, c-Myc, Bax, Cyt-c, caspase-9, and caspase-3 significantly increased, and those of Bcl-2 and Bcl-2/Bax significantly decreased, following Cr (VI) exposure, while Se restored the expression of these genes. In conclusion, our findings suggest that SeY can protect against Cr (VI)-induced dysfunction and apoptosis by regulating the mitogen-activated protein kinase pathway activated by oxidative stress in broiler kidney tissues.

Selenium Deficiency Aggravates Heat Stress Pneumonia in Chickens by Disrupting the M1/M2 Balance

Selenium (Se) is an essential trace element found in the body. Se deficiency and M1/M2 imbalance are closely related to inflammation. Heat stress can decrease immune function and cause inflammation. In order to investigate whether Se deficiency can aggravate pneumonia caused by heat stress and the role of M1/M2 imbalance in the occurrence of pneumonia, 100 AA broilers were divided into two groups and fed the conventional diet (0.2 mg/kg Se) and the Se-deficient diet (0.03 mg/kg Se). After 40 days of feeding, the normal feeding group was randomly divided into a control group and a heat stress group. At the same time, the Se-deficient diet feeding group was randomly divided into a low Se group and a low Se heat stress group, with 25 chickens in each group. The model was established by exposure at 40℃. Six hours later, broilers were euthanized, and their lung tissues were collected. Hematoxylin and eosin staining, immunofluorescence, quantitative real-time PCR, and western blotting were used to detect lung histopathological changes and the expression of M1/M2 markers, nuclear receptor-κB (NF-κB) pathway genes, and heat shock proteins. Meanwhile, the activity and content of oxidative stress-related indices were also detected. We found that the expression of interleukin-1β, interleukin-6, interleukin-12, and tumor necrosis factor-α was upregulated and the expression of interleukin-2, interleukin-10, and interferon-γ was downregulated. Immunofluorescence showed that the expression of CD16 was increased, the expression of CD163 was weakened, and the M1/M2 imbalance was present. In addition, the NF-κB pathway was activated by the increased expressions of heat shock proteins and oxidative stress. There was an increase in malondialdehyde, nitric oxide, and inducible nitric oxide synthase content, while the activity of total antioxidant capacity, glutathione peroxidase, catalase, and superoxide dismutase decreased, and the expression of NF-κB and cyclooxygenase-2 increased. These results suggest that low Se induces M1/M2 imbalance through oxidative stress activation of the NF-κB pathway and aggravates lung tissue inflammation caused by heat stress. This study offers a theoretical basis for exploring the pathogenesis of various kinds of inflammation induced by Se deficiency from the perspective of M1/M2 and provides a reference for the prevention of such diseases.

Supplementation of diet with Brazil nut modulates body composition, bone parameters, and lipid peroxidation in Wistar rats

Oxidative stress, adipose tissue, and bone compartments can be disturbed in chronic diseases. Non-pharmacological strategies, such as Brazil nuts (BNs), can improve these parameters. This study evaluated the effects of BN supplementation at different concentrations on body composition, lipid profile, and peroxidation in healthy rats. Male Wistar rats were divided into three groups: control (CT), Brazil nut 5% (BN5), and Brazil nut 10% (BN10) groups. Body composition, brown adipose tissue (BAT), plasma lipid peroxidation, and lipid profile were evaluated in the three groups. The BN5 group showed an improvement in all bone parameters compared with that of the CT group (p  < .0001). The BN5 and BN10 groups showed reduced plasma lipid peroxidation compared with that of the CT group (p = .0009), whereas the BN10 group presented lower BAT lipid peroxidation than that of the other groups (p = .01). High-density lipoprotein-cholesterol (HDL-c) levels were higher in the BN5 group than in the CT group (p = .01). Conclusively, the use of BNs in a controlled manner promoted improvement in bone parameters, HDL-c levels, and lipid peroxidation in healthy rats. PRACTICAL APPLICATIONS: Nuts has been included in the diet because of their versatility, acceptance, and easy access. Among them, Brazil nut (BN) is considered one of the major known food sources of selenium as well as a source of fibers, unsaturated fatty acids, and phenolic compounds. Studies have shown that BN supplementation is effective in reducing oxidative stress, inflammation, lipid peroxidation, and selenium deficiency when used as a non-pharmacological strategy in experimental models of chronic diseases and in clinical trials. The present study showed that controlled administration of BN improved bone parameters, high-density lipoprotein-cholesterol levels, and lipid peroxidation in healthy rats. Therefore, BN is a promising non-pharmacological agent for the prevention of the onset of chronic non-communicable diseases.

Association between Selenium Status and Chronic Kidney Disease in Middle-Aged and Older Chinese Based on CHNS Data

Background: The association between selenium and chronic kidney disease (CKD) remains controversial. Population studies with large samples facilitate the reliability of conclusions. Objective: In this study, we aimed to describe the prevalence of a CKD association with selenium intake in middle-aged and older Chinese. Methods: Data for this study were obtained from the China Health and Nutrition Survey (CHNS). A total of 5381 participants (aged ≥ 45) with biochemical test data were included in the study. Logistic regression models were used to examine the association between diet selenium intake (quartile) and the prevalence of CKD. Results: A total of 942 (17.01%) participants had CKD. The prevalence of CKD was 23.33%, 20.32%, 14.98%, and 9.25% among participants with average selenium intakes of 21.5 ± 4.82, 33.1 ± 2.79, 43.8 ± 3.70, and 67.0 ± 13.97 µg/day, respectively. In the fully adjusted model (Model 3), across the quartiles of selenium intake, the ORs for the prevalence of CKD were 1.00, 1.09 (95% CI 0.69–1.73), 0.82 (95% CI 0.49–1.38), and 0.43 (95% CI 0.22–0.85). The protein intake had a certain diagnostic significance for the selenium intake. Conclusions: An adequate selenium intake may have a positive effect on CKD. The influence of individual weight and location on the effect of selenium on CKD needs to be further explored.

Antidepressant-Like Effect of a Selenoindolizine in Mice: In Vivo and In Silico Evidence for the Involvement of the Serotonergic 5-HT2A/C Receptors

The monoaminergic dysfunction plays a central role in major depressive disorder (MDD), a mental disturbance associated with constant feeling of sadness and lack of interest. The available treatments do not present a desirable efficacy and some of them provoke several adverse effects. In this context, organoselenium compounds and molecules containing the indolizine nucleus have demonstrated interesting pharmacological properties, including antidepressant-like effects. In this study, the antidepressant-like effect of 2-phenyl-1-(phenylselanyl)indolizine (SeI), a selenium-containing indolizine derivative, was investigated on the forced swimming test (FST) and on the tail suspension test (TST) in male Swiss mice. The involvement of the serotonergic system in this effect was also accessed. The selenium compound SeI (10-100 mg/kg, intragastrical (i.g.)) was administered 0.5 h before the behavioral tests, and it diminished the immobility on both FST and TST experiments, which is an indication of antidepressant-like effect. No changing in the locomotor motion was observed in the open-field test (OFT). The anti-immobility effect of SeI was not altered by the preadministration of the selective serotonergic receptor antagonists ondansetron (1 mg/kg, intraperitoneally (i.p.), antagonist of 5-HT₃ receptor) and WAY100635 (0.1 mg/kg, subcutaneous route (s.c.), antagonist of 5-HT_1A receptor). In contrast, the preadministration of ketanserin (1 mg/kg, i.p., antagonist of 5-HT_2A/C receptor) blocked this effect, demonstrating that the antidepressant-like effect of SeI involves 5-HT_2A/C. In addition, molecular docking studies showed a strong interaction between SeI and the receptors of 5-HT_2A and 5-HT_2C. The toxicological results demonstrated that SeI has low potential to cause adverse effects in mice. It was found that the antidepressant-like effect of SeI is related to modulation of the serotonergic system, and this selenium compound could be included in new treatment approaches for MDD.

Transcriptome analysis provides new insight into the distribution and transport of selenium and its associated metals in selenium-rich rice

Selenium is an essential trace element for humans and obtained from diary diets. The consumption of selenium-rich agricultural food is an efficient way to obtain selenium, but the quality and safety of selenium-rich agro-food are always affected by their associated heavy metals, even poses a potential threaten to human health. In this research, a sampling survey of heavy metals contents in selenium-rich rice was conducted, 182 sets of selenium-rich rice samples were collected from five selenium-rich rice-producing areas of China, and the accumulation of selenium and cadmium were found to be associated in rice and soil. Subsequently, a pot experiment was performed in the greenhouse via treating the soil samples with 12 different concentrations of selenium and heavy metals, and the contents of selenium and cadmium in rice grain were confirmed to be significantly associated. Moreover, transcriptome analysis revealed that the up-regulation of transporter-coding may promote the absorption of selenium and cadmium. The expression of antioxidant-coding genes and cadmium chelator transporter coding-genes was up-regulated to reduce the toxicity of cadmium. Meanwhile, the up-regulation of key genes of the ascorbic acid-glutathione metabolic pathway were responsible for the association between selenium and cadmium in Se-rich rice. Our work suggested the correlation between selenium and cadmium accumulation in selenium-rich rice, clarified their accumulation mechanism, provides a direction for the scientific production of selenium-rich agro-foods.

The Role and Mechanism of Essential Selenoproteins for Homeostasis

Selenium (Se) is one of the essential trace elements that plays a biological role in the body, mainly in the form of selenoproteins. Selenoproteins can be involved in the regulation of oxidative stress, endoplasmic reticulum (ER) stress, antioxidant defense, immune and inflammatory responses and other biological processes, including antioxidant, anti-inflammation, anti-apoptosis, the regulation of immune response and other functions. Over-loading or lack of Se causes certain damage to the body. Se deficiency can reduce the expression and activity of selenoproteins, disrupt the normal physiological function of cells and affect the body in antioxidant, immunity, toxin antagonism, signaling pathways and other aspects, thus causing different degrees of damage to the body. Se intake is mainly in the form of dietary supplements. Due to the important role of Se, people pay increasingly more attention to Se-enriched foods, which also lays a foundation for better research on the mechanism of selenoproteins in the future. In this paper, the synthesis and mechanism of selenoproteins, as well as the role and mechanism of selenoproteins in the regulation of diseases, are reviewed. Meanwhile, the future development of Se-enriched products is prospected, which is of great significance to further understand the role of Se.

Natural selenium stress influences the changes of antibiotic resistome in seleniferous forest soils

BACKGROUND

Metal(loid)s can promote the spread and enrichment of antibiotic resistance genes (ARGs) in the environment through a co-selection effect. However, it remains unclear whether exposure of microorganisms to varying concentrations of selenium (Se), an essential but potentially deleterious metal(loid) to living organisms, can influence the migration and distribution of ARGs in forest soils.

RESULTS

Precisely 235 ARGs conferring resistance to seven classes of antibiotics were detected along a Se gradient (0.06-20.65 mg kg^-1) across 24 forest soils. (flor)/(chlor)/(am)phenicol resistance genes were the most abundant in all samples. The total abundance of ARGs first increased and then decreased with an elevated available Se content threshold of 0.034 mg kg^-1 (P = 2E-05). A structural equation model revealed that the dominant mechanism through which Se indirectly influences the vertical migration of ARGs is by regulating the abundance of the bacterial community. In addition, the methylation of Se (mediated by tehB) and the repairing of DNA damages (mediated by ruvB and recG) were the dominant mechanisms involved in Se resistance in the forest soils. The co-occurrence network analysis revealed a significant correlated cluster between Se-resistance genes, MGEs and ARGs, suggesting the co-transfer potential. Lelliottia amnigena YTB01 isolated from the soil was able to tolerate 50 μg mL^-1 ampicillin and 1000 mg kg^-1 sodium selenite, and harbored both Se resistant genes and ARGs in the genome.

CONCLUSIONS

Our study demonstrated that the spread and enrichment of ARGs are enhanced under moderate Se pressure but inhibited under severe Se pressure in the forest soil (threshold at 0.034 mg kg^-1 available Se content). The data generated in this pilot study points to the potential health risk associated with Se contamination and its associated influence on ARGs distribution in soil.

The health benefits of selenium in food animals: a review

Selenium is an essential trace mineral important for the maintenance of homeostasis in animals and humans. It evinces a strong antioxidant, anti-inflammatory and potential antimicrobial capacity. Selenium biological function is primarily achieved by its presence in selenoproteins as a form of selenocysteine. Selenium deficiency may result in an array of health disorders, affecting many organs and systems; to prevent this, dietary supplementation, mainly in the forms of organic (i.e., selenomethionine and selenocysteine) inorganic (i.e., selenate and selenite) sources is used. In pigs as well as other food animals, dietary selenium supplementation has been used for improving growth performance, immune function, and meat quality. A substantial body of knowledge demonstrates that dietary selenium supplementation is positively associated with overall animal health especially due to its immunomodulatory activity and protection from oxidative damage. Selenium also possesses potential antiviral activity and this is achieved by protecting immune cells against oxidative damage and decreasing viral replication. In this review we endeavor to combine established and novel knowledge on the beneficial effects of dietary selenium supplementation, its antioxidant and immunomodulatory actions, and the putative antimicrobial effect thereof. Furthermore, our review demonstrates the gaps in knowledge pertaining to the use of selenium as an antiviral, underscoring the need for further in vivo and in vitro studies, particularly in pigs.

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.

The Role of Selenium Nanoparticles in Agriculture and Food Technology

Selenium (Se) is an essential micronutrient for diverse organisms such as mammals, bacteria, some insects and nematodes, archaea, and algae, as it is involved in a large number of physiological and metabolic processes and is part of approximately 25 selenoproteins in mammals. In plants, Se has no essential metabolic role, high concentrations of inorganic Se can lead to the formation of Se-amino acids, and its incorporation into selenoproteins can generate toxicity. Conversely, low doses of Se can trigger a variety of beneficial effects as an antioxidant, antimicrobial, or stress-modulating agent without being an essential element. Therefore, Se can generate toxicity depending on the dose and the chemical form in which it is supplied. Selenium nanoparticles (SeNPs) have emerged as an approach to reduce this negative effect and improve its biological properties. In turn, SeNPs have a wide range of potential advantages, making them an alternative for areas such as agriculture and food technology. This review focuses on the use of SeNPs and their different applications as antimicrobial agents, growth promoters, crop biofortification, and nutraceuticals in agriculture. In addition, the utilization of SeNPs in the generation of packaging with antioxidant and antimicrobial traits and Se enrichment of animal source foods for human consumption as part of food technology is addressed. Additionally, possible action mechanisms and potential adverse effects are discussed. The concentration, size, and synthesis method of SeNPs are determining factors of their biological properties.

Mediterranean-Type Diets as a Protective Factor for Asthma and Atopy

We are currently riding the second wave of the allergy epidemic, which is ongoing in affluent societies, but now also affecting developing countries. This increase in the prevalence of atopy/asthma in the Western world has coincided with a rapid improvement in living conditions and radical changes in lifestyle, suggesting that this upward trend in allergic manifestations may be associated with cultural and environmental factors. Diet is a prominent environmental exposure that has undergone major changes, with a substantial increase in the consumption of processed foods, all across the globe. On this basis, the potential effects of dietary habits on atopy and asthma have been researched rigorously, but even with a considerable body of evidence, clear associations are far from established. Many factors converge to obscure the potential relationship, including methodological, pathophysiological and cultural differences. To date, the most commonly researched, and highly promising, candidate for exerting a protective effect is the so-called Mediterranean diet (MedDi). This dietary pattern has been the subject of investigation since the mid twentieth century, and the evidence regarding its beneficial health effects is overwhelming, although data on a correlation between MedDi and the incidence and severity of asthma and atopy are inconclusive. As the prevalence of asthma appears to be lower in some Mediterranean populations, it can be speculated that the MedDi dietary pattern could indeed have a place in a preventive strategy for asthma/atopy. This is a review of the current evidence of the associations between the constituents of the MedDi and asthma/atopy, with emphasis on the pathophysiological links between MedDi and disease outcomes and the research pitfalls and methodological caveats which may hinder identification of causality. MedDi, as a dietary pattern, rather than short-term supplementation or excessive focus on single nutrient effects, may be a rational option for preventive intervention against atopy and asthma.

Hyperglycemia and Loss of Redox Homeostasis in COVID-19 Patients

The infection with SARS-CoV-2 impairs the glucose−insulin axis and this contributes to oxidative (OS) and nitrosative (NSS) stress. Here, we evaluated changes in glucose metabolism that could promote the loss of redox homeostasis in COVID-19 patients. This was comparative cohort and analytical study that compared COVID-19 patients and healthy subjects. The study population consisted of 61 COVID-19 patients with and without comorbidities and 25 healthy subjects (HS). In all subjects the plasma glucose, insulin, 8-isoprostane, Vitamin D, H2S and 3-nitrotyrosine were determined by ELISA. The nitrites (NO2−), lipid-peroxidation (LPO), total-antioxidant-capacity (TAC), thiols, glutathione (GSH) and selenium (Se) were determined by spectrophotometry. The glucose, insulin and HOMA-IR (p < 0.001), 8-isoprostanes, 3-nitrotyrosine (p < 0.001) and LPO were increased (p = 0.02) while Vitamin D (p = 0.01), H2S, thiols, TAC, GSH and Se (p < 0.001) decreased in COVID-19 patients in comparison to HS. The SARS-CoV-2 infection resulted in alterations in the glucose−insulin axis that led to hyperglycemia, hyperinsulinemia and IR in patients with and without comorbidities. These alterations increase OS and NSS reflected in increases or decreases in some oxidative markers in plasma with major impact or fatal consequences in patients that course with metabolic syndrome. Moreover, subjects without comorbidities could have long-term alterations in the redox homeostasis after infection.

Functional food: complementary to fight against COVID-19

Background

The novel coronavirus has embarked on a global pandemic and severe mortality with limited access for its treatments and medications. For the lack of time, research, and enough efficacy, most vaccines are underdeveloped or unreachable to society. However, many recent studies suggest various alternative, complementary remedies for COVID-19, which are functional foods. This review provides an overview of how functional foods can play a great role through modulating the host immune system, generating antiviral activities, and synthesizing biologically active agents effective against the coronavirus.

Main body

This review article summarizes the natural defense mechanisms in tackling SARS-CoV-2 alongside conventional therapeutic options and their corresponding harmful side effects. By analyzing bioactive components of functional foods, we have outlined its different contributions to human health and its potential immunomodulatory and antiviral properties that can enhance resistivity to viral infection. Moreover, we have provided a myriad of accessible and cost-effective functional foods that could be further investigated to target specific key symptoms of COVID-19 infections. Finally, we have found various functional foods with potent bioactive compounds that can inhibit or prevent COVID-19 infections and disease progression.

Short conclusion

Numerous functional foods can help the body fight COVID-19 through several mechanisms such as the reduced release of pro-inflammatory cytokines, reduced expression of ACE2 receptors in cells, and inhibiting essential enzymes in SARS-CoV-2.

Activation of the GPX4/TLR4 Signaling Pathway Participates in the Alleviation of Selenium Yeast on Deltamethrin-Provoked Cerebrum Injury in Quails

Deltamethrin (DLM) is a member of pyrethroid pesticide widely applied for agriculture and aquaculture, and its residue in the environment seriously threatens the bio-safety. The cerebrum might be vulnerable to pesticide-triggered oxidative stress. However, there is no specific antidote for treating DLM-triggered cerebral injury. Selenium (Se) is an essential trace element functionally forming selenoprotein glutathione peroxidase (GPX) in antioxidant defense. Se yeast (SY) is a common and effective organic form of Se supplement with high selenomethionine content. Accordingly, this study focused on investigating the therapeutic potential of SY on DLM-induced cerebral injury in quails after chronically exposing to DLM and exploring the underlying mechanisms. Quails were treated with/without SY (0.4 mg kg^-1 SY added in standard diet) in the presence/absence of DLM (45 mg kg^-1 body weight intragastrically) for 12 weeks. The results showed SY supplementation ameliorated DLM-induced cerebral toxicity. Concretely, SY elevated the content of Se and increased GPX4 level in DLM-treated quail cerebrum. Furthermore, SY enhanced antioxidant defense system by upregulating nuclear factor-erythroid-2-related factor 2 (Nrf2) associated members. Inversely, SY diminished the changes of apoptosis- and inflammation-associated proteins and genes including toll-like receptor 4 (TLR4). Collectively, our results suggest that dietary SY protects against DLM-induced cerebral toxicity in quails via positively regulating the GPX4/TLR4 signaling pathway. GPX4 may be a potential therapeutic target for insecticide-induced biotoxicity.

Effects of Selenium Nanoparticles on Preventing Patulin-Induced Liver, Kidney and Gastrointestinal Damage

Patulin (PAT) is a toxic fungal metabolite, and oxidative damage was proved to be its important toxicity mechanism. Selenium nanoparticles (SeNPs) were prepared by reducing sodium selenite with chitosan as a stabilizer and used for preventing PAT-induced liver, kidney and gastrointestinal damage. SeNPs have good dispersibility, in vitro antioxidant activity, and are much less cytotoxic than sodium selenite. Cell culture studies indicated that SeNPs can effectively alleviate PAT-induced excessive production of intracellular ROS, the decline of glutathione peroxidase activity, and the suppression of cell viability. Evaluation of serum biochemical parameters, histopathology, oxidative stress biomarkers and activities of antioxidant enzymes in a mouse model showed that pre-treatment with SeNPs (2 mg Se/kg body weight) could ameliorate PAT-induced oxidative damage to the liver and kidneys of mice, but PAT-induced gastrointestinal oxidative damage and barrier dysfunction were not recovered by SeNPs, possibly because the toxin doses suffered by the gastrointestinal as the first exposed tissues exceeded the regulatory capacity of SeNPs. These results suggested that a combination of other strategies may be required to completely block PAT toxicity.

A Comprehensive Review on Selenium and Its Effects on Human Health and Distribution in Middle Eastern Countries

Selenium (Se) is an important microelement with numerous positive effects on human health and diseases. It is important to specify that the status and consumption of Se are for a specific community as the levels of Se are extremely unpredictable between different populations and regions. Our existing paper was based on the impacts of Se on human health and disease along with data on the Se levels in Middle Eastern countries. Overall, the findings of this comprehensive review show that the consumption and levels of Se are inadequate in Middle Eastern nations. Such findings, together with the growing awareness of the importance of Se to general health, require further work primarily on creating an acceptable range of blood Se concentration or other measures to determine optimal Se consumption and, consequently, to guarantee adequate Se supplementation in populations at high risk of low Se intake.

Provision of Small-Quantity Lipid-Based Nutrient Supplements Increases Plasma Selenium Concentration in Pregnant Women in Malawi: A Secondary Outcome of a Randomized Controlled Trial

Background

Pregnant women in Malawi are at risk of selenium deficiency, which can have adverse effects on pregnancy outcomes. Interventions for improving selenium status are needed.

Objectives

To assess the effect of provision of small-quantity lipid-based nutrient supplements (SQ-LNSs) to Malawian women during pregnancy on their plasma selenium concentrations at 36 wk of gestation.

Methods

Pregnant women (≤20 wk of gestation) were randomly assigned to receive daily either: 1) iron and folic acid (IFA); 2) multiple micronutrients (MMN; 130 µg selenium per capsule); or 3) SQ-LNS (130 µg selenium/20 g). Plasma selenium concentrations were measured by inductively coupled plasma mass spectrometry at baseline and after ≥16 wk of intervention (at 36 wk of gestation) and compared by intervention group.

Results

At 36 wk of gestation, median (quartile 1, quartile 3) plasma selenium concentrations (micromoles per liter) were 0.96 (0.73, 1.23), 0.94 (0.78, 1.18), and 1.01 (0.85, 1.28) in the IFA, MMN, and SQ-LNS groups, respectively. Geometric mean (GM) plasma selenium concentration was 5.4% (95% CI: 1.8%, 9.0%) higher in the SQ-LNS group than in the MMN group and tended to be higher than in the IFA group (+4.2%; 95% CI: 1.0%, 7.8%). The prevalence of adjusted plasma selenium concentrations <1 µmol/L was 55.1%, 57.8%, and 47.3% in the IFA, MMN, and SQ-LNS groups, respectively; it was lower in the SQ-LNS group than in the MMN group, OR = 0.44 (95% CI: 0.24, 0.83), and tended to be lower than in the IFA group, OR = 0.54 (95% CI: 0.29, 1.03). There was a significant interaction between baseline plasma selenium concentration and intervention group (P = 0.003). In the lowest tertile of baseline selenium concentrations, GM plasma selenium concentration was higher, and the prevalence of low values was lower in the SQ-LNS group compared with the MMN and IFA groups at 36 wk of gestation (P ≤ 0.007).

Conclusions

Provision of SQ-LNS containing selenium to pregnant women can be an effective strategy for improving their selenium status.This trial was registered at clinicaltrials.gov (identifier: NCT01239693).

Effect of Brazil Nuts on Selenium Status, Blood Lipids, and Biomarkers of Oxidative Stress and Inflammation: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Tree nuts, including Brazil nuts, have been hypothesized to impact cardiovascular health through the modulation of oxidative stress and inflammation. Nonetheless, a quantitative analysis of these effects has not been performed. Therefore, the aim of this study was to systematically revise and quantify the effect of Brazil nut intervention on selenium status, blood lipids, and biomarkers of oxidative stress and inflammation using a meta-analytical approach. To meet the goals of this study, a systematic search of PubMed, EMBASE, and Web of Science databases of published randomised clinical trials reporting on dietary interventions with Brazil nuts and their effects on selenium status, blood lipids, and markers of oxidative stress and inflammation was performed. Eight articles were included for systematic review and meta-analysis. Based on the conducted analysis, a significant positive effect of Brazil nuts on selenium blood concentration (SMD = 6.93, 95% CI: 3.99; 9.87) was found. Additionally, a positive effect of Brazil nut intervention on glutathione peroxidase activity (SMD = 0.53, 95% CI: 0.07; 0.99) was observed. However, no significant results were found when considering blood lipid levels, including results for total cholesterol (SMD = −0.22, 95% CI: −0.57; 0.14), HDL cholesterol (SMD = −0.04, 95% CI: −0.28; 0.19) and LDL cholesterol (SMD = −0.15; 95% CI: −0.43; 0.13). In conclusion, the findings from this study suggest that Brazil nut consumption improves selenium status and exerts antioxidant effects, which could be considered a potential pathway for the prevention of metabolic disorders related to altered blood lipid profiles. However, further studies are needed to elucidate the effect of Brazil nuts toward blood lipid profile, also preferably controlling for other biomarkers.

Evaluating the effect of selenium on spatial memory impairment induced by sleep deprivation

Sleep deprivation (SD) impairs memory due to disturbing oxidative stress parameters. Selenium is a main component of several antioxidant enzymes and provides a neuroprotective effect. The present study aimed to investigate the potential neuroprotective effect of chronic selenium administration on cognitive impairments induced by chronic SD. Adult male Wister rats were randomly assigned into five groups (n = 12/group). The SD was induced in rats using modified multiple platform model. Selenium (6 µg/kg of animal's body weight) was administered to rats via oral gavage for 6 weeks. The spatial learning and memory were assessed using the radial arm water maze (RAWM). Moreover, we measured the levels of reduced glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG, catalase, glutathione peroxidase (GPx), superoxide dismutase (SOD), thiobarbituric acid reactive substances (TBARS) and brain derived neurotrophic factor (BDNF) in the hippocampus. The results indicate that short- and long-term memory were impaired by chronic sleep deprivation (P < 0.05), while selenium administration prevented this effect. Moreover, selenium normalized antioxidants activities which were reduced by SD such as: catalase (P < 0.05), and SOD (P < 0.05), and significantly enhanced the ratio of GSH/GSSG in sleep-deprived rats (P < 0.05), without significant alteration of BDNF (P > 0.05), GSH (P > 0.05), or TBARS levels (P > 0.05). In conclusion, chronic SD induced memory impairment, and chronic treatment with selenium prevented this impairment by normalizing antioxidant enzymes activities in the hippocampus.

The Effects of Selenium on Bone Health: From Element to Therapeutics

Osteoporosis, characterized by low bone mass and a disruption of bone microarchitecture, is traditionally treated using drugs or lifestyle modifications. Recently, several preclinical and clinical studies have investigated the effects of selenium on bone health, although the results are controversial. Selenium, an important trace element, is required for selenoprotein synthesis and acts crucially for proper growth and skeletal development. However, the intake of an optimum amount of selenium is critical, as both selenium deficiency and toxicity are hazardous for health. In this review, we have systematically analyzed the existing literature in this field to determine whether dietary or serum selenium concentrations are associated with bone health. In addition, the mode of administration of selenium as a supplement for treating bone disease is important. We have also highlighted the importance of using green-synthesized selenium nanoparticles as therapeutics for bone disease. Novel nanobiotechnology will be a bridgehead for clinical applications of trace elements and natural products.

Association of selenium, zinc and copper concentrations during pregnancy with birth weight: A systematic review and meta-analysis

BACKGROUND

Normal fetal growth is associated with maternal nutrition. Trace elements play important roles in fetus growth. This review aims to provide a summary of the literature evaluating the relation between selenium, zinc and copper levels during pregnancy with birth weight.

METHOD

A systematic literature search was conducted in Medline database (PubMed), Scopus, Web of science and Google scholar up to September 2020. Fifty observational studies were included in the final analyses. The desired pooled effect size was considered as standardized mean differences with 95 % CI or correlation. Cochran's Q statistic was used to test the heterogeneity between the included studies (I²).

RESULT

A significant differences were found between pooled standardized mean differences (SMD) of umbilical cord blood copper levels in small-for-gestational age birth weight (SGA) and appropriate-for-gestational age birth weight (AGA) (SMD: 0.34 μg/L, 95 % CI: 0.13 to 0.56). There was a significant pooled correlation between umbilical cord blood selenium concentrations and birth weight (r: 0.08, 95 % CI: 0.01 to 0.16). A significant pooled correlation was found between umbilical cord blood zinc concentrations and birth weight (r: 0.09, 95 % CI: 0.04 to 0.15), with significant heterogeneity (I² % = 0.63). There was significant positive association between maternal blood zinc concentrations and birth weight.

CONCLUSION

Findings showed the association of trace elements including selenium, zinc and copper during pregnancy with birth weight. There was significant correlation between umbilical cord and maternal blood selenium and zinc levels with birth weight. The umbilical cord blood copper levels in SGA birth weight was higher than copper levels in AGA birth weight.

The Role of Methyl Donors of the Methionine Cycle in Gastrointestinal Infection and Inflammation

Vitamin deficiency is well known to contribute to disease development in both humans and other animals. Nonetheless, truly understanding the role of vitamins in human biology requires more than identifying their deficiencies. Discerning the mechanisms by which vitamins participate in health is necessary to assess risk factors, diagnostics, and treatment options for deficiency in a clinical setting. For researchers, the absence of a vitamin may be used as a tool to understand the importance of the metabolic pathways in which it participates. This review aims to explore the current understanding of the complex relationship between the methyl donating vitamins folate and cobalamin (B12), the universal methyl donor S-adenosyl-L-methionine (SAM), and inflammatory processes in human disease. First, it outlines the process of single-carbon metabolism in the generation of first methionine and subsequently SAM. Following this, established relationships between folate, B12, and SAM in varying bodily tissues are discussed, with special attention given to their effects on gut inflammation.

Selenotranscriptome Network in Non-alcoholic Fatty Liver Disease

Observational studies indicate that selenium may contribute to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Transcriptomic exploration of the aetiology and progression of NAFLD may offer insight into the role selenium plays in this disease. This study compared gene expression levels of known selenoprotein pathways between individuals with a healthy liver to those with NAFLD. Publicly available gene expression databases were searched for studies that measured global gene expression in liver samples from patients with steatosis and non-alcoholic steatohepatitis (NASH) and healthy controls (with [HOC] or without [HC] obesity). A subset of five selenoprotein-related pathways (164 genes) were assessed in the four datasets included in this analysis. The gene TXNRD3 was less expressed in both disease groups when compared with HOC. SCLY and SELENOO were less expressed in NASH when compared with HC. SELENOM, DIO1, GPX2, and GPX3 were highly expressed in NASH when compared to HOC. Disease groups had lower expression of iron-associated transporters and higher expression of ferritin-encoding sub-units, consistent with dysregulation of iron metabolism often observed in NAFLD. Our bioinformatics analysis suggests that the NAFLD liver may have lower selenium levels than a disease-free liver, which may be associated with a disrupted iron metabolism. Our findings indicate that gene expression variation may be associated with the progressive risk of NAFLD.

Selenomethionine modulates insulin secretion in the MIN6-K8 mouse insulinoma cell line

Selenium is an essential trace element of interest for its potential role in glucose homeostasis. The present study investigated the impact of selenium supplementation as selenomethionine (SeMet) on insulin secretion in MIN6-K8 cells, a pancreatic β-cell model. We found that SeMet enhanced percent glucose-induced insulin secretion, while also increasing tolbutamide- and KCl-induced percent insulin secretion. RNA-sequencing showed that SeMet supplementation altered expression of several selenoproteins, including glutathione peroxidase 3 (Gpx3) and selenoprotein P (SelP). Targeted knockdown of Gpx3 increased both percent and total insulin release, while SelP knockdown increased insulin content and insulin release. Collectively, these studies support a putative role for selenium and selenoproteins in the regulation of insulin secretion, glucose homeostasis, and diabetes risk.

The Effect of Organoselenium Compounds on Histone Deacetylase Inhibition and Their Potential for Cancer Therapy

Genetic and epigenetic changes alter gene expression, contributing to cancer. Epigenetic changes in cancer arise from alterations in DNA and histone modifications that lead to tumour suppressor gene silencing and the activation of oncogenes. The acetylation status of histones and non-histone proteins are determined by the histone deacetylases and histone acetyltransferases that control gene transcription. Organoselenium compounds have become promising contenders in cancer therapeutics. Apart from their anti-oxidative effects, several natural and synthetic organoselenium compounds and metabolites act as histone deacetylase inhibitors, which influence the acetylation status of histones and non-histone proteins, altering gene transcription. This review aims to summarise the effect of natural and synthetic organoselenium compounds on histone and non-histone protein acetylation/deacetylation in cancer therapy.

Sex-dimorphic distribution and anti-oxidative effects of selenomethionine and Se-methylselenocysteine supplementation

Selenium (Se) is a vital trace element in human beings and is essential for protection against oxidative stress. This study aimed to investigate the accumulation and antioxidant effects of two organic seleniums, L-selenomethionine (SM) and L-Se-methylselenocysteine (SMC), through in vivo and in vitro experiments. L02 cells were pretreated with 10 nM SM or SMC for 24 h, followed by exposure to 100 nM of H₂O₂. Cell viability, apoptosis, and antioxidant capacity were detected to evaluate SM and SMC's protective effect. Organic selenium (SM and SMC) and inorganic selenium (sodium selenite, SS) were compared in terms of their in vivo accumulation and antioxidant capacity when supplemented daily and subsequently deprived in SD rats. Our results show that SM or SMC pre-treatment could significantly prevent elevated apoptosis and declined antioxidant ability. We found that organic Se supplementation resulted in higher Se accumulation than inorganic Se in the liver and kidney. The antioxidant capacity of liver and kidney tissues from rats fed with either organic selenium was significantly improved and was higher than that of SS. In summary, this study suggests that organic selenium supplements are more effective in facilitating Se accumulation in liver and kidney, enhancing antioxidant capacities, thereby protecting cells from oxidative stress. PRACTICAL APPLICATION: This study compared the antioxidant capacity of sodium selenite, L-selenomethionine, and L-Se-methylselenocysteine in vitro and in vivo. The results showed that organic selenium has a stronger antioxidant capacity and that significant differences exist in its absorption and conversion in male and female rats. Our results provide theoretical guidance for dietary supplementation of selenium.

Associations of Habitual Mineral Intake with New-Onset Prediabetes/Diabetes after Acute Pancreatitis

Associations between habitual dietary intake of minerals and glucose metabolism have been extensively studied in relation to metabolic disorders. However, similar research has yet to be conducted in individuals after acute pancreatitis (AP). The main aim was to investigate the associations between habitual intake of 13 minerals and glycaemic status: new-onset prediabetes/diabetes after AP (NODAP), pre-existing prediabetes/type 2 diabetes (T2DM), and normoglycaemia after AP (NAP). Associations between the dietary intake of minerals and markers of glucose metabolism (glycated haemoglobin and fasting plasma glucose) were also studied. The EPIC-Norfolk food frequency questionnaire was used in a cross-sectional fashion to determine the habitual intake of 13 dietary minerals. ANCOVA as well as multiple linear regression analyses were conducted and five statistical models were built to adjust for covariates. The study included 106 individuals after AP. In the NODAP group, intake of 4 minerals was significantly less when compared with the NAP group: iron (B = -0.076, p = 0.013), nitrogen (B = -0.066, p = 0.003), phosphorous (B = -0.046, p = 0.006), and zinc (B = -0.078, p = 0.001). Glycated haemoglobin was significantly associated with iodine intake (B = 17.763, p = 0.032) and manganese intake (B = -17.147, p = 0.003) in the NODAP group. Fasting plasma glucose was significantly associated with manganese intake (B = -2.436, p = 0.027) in the NODAP group. Habitual intake of minerals differs between individuals with NODAP, T2DM, and NAP. Prospective longitudinal studies and randomised controlled trials are now warranted to further investigate the associations between mineral intake and NODAP.

Trace Element Selenium Effectively Alleviates Intestinal Diseases

Selenium (Se) is an essential trace element in the body. It is mainly used in the body in the form of selenoproteins and has a variety of biological functions. Intestinal diseases caused by chronic inflammation are among the most important threats to human health, and there is no complete cure at present. Due to its excellent antioxidant function, Se has been proven to be effective in alleviating intestinal diseases such as inflammatory bowel diseases (IBDs). Therefore, this paper introduces the role of Se and selenoproteins in the intestinal tract and the mechanism of their involvement in the mediation of intestinal diseases. In addition, it introduces the advantages and disadvantages of nano-Se as a new Se preparation and traditional Se supplement in the prevention and treatment of intestinal diseases, so as to provide a reference for the further exploration of the interaction between selenium and intestinal health.

Maternal malnutrition and anaemia in India: dysregulations leading to the 'thin-fat' phenotype in newborns

Maternal and child malnutrition and anaemia remain the leading factors for health loss in India. Low birth weight (LBW) offspring of women suffering from chronic malnutrition and anaemia often exhibit insulin resistance and infantile stunting and wasting, together with increased risk of developing cardiometabolic disorders in adulthood. The resulting self-perpetuating and highly multifactorial disease burden cannot be remedied through uniform dietary recommendations alone. To inform approaches likely to alleviate this disease burden, we implemented a systems-analytical approach that had already proven its efficacy in multiple published studies. We utilised previously published qualitative and quantitative analytical results of rural and urban field studies addressing maternal and infantile metabolic and nutritional parameters to precisely define the range of pathological phenotypes encountered and their individual biological characteristics. These characteristics were then integrated, via extensive literature searches, into metabolic and physiological mechanisms to identify the maternal and foetal metabolic dysregulations most likely to underpin the 'thin-fat' phenotype in LBW infants and its associated pathological consequences. Our analyses reveal hitherto poorly understood maternal nutrition-dependent mechanisms most likely to promote and sustain the self-perpetuating high disease burden, especially in the Indian population. This work suggests that it most probably is the metabolic consequence of 'ill-nutrition' - the recent and rapid dietary shifts to high salt, high saturated fats and high sugar but low micronutrient diets - over an adaptation to 'thrifty metabolism' which must be addressed in interventions aiming to significantly alleviate the leading risk factors for health deterioration in India.