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[Selenium and zinc: "antioxidants" for healthy aging?].
Steinbrenner, H, Klotz, LO
Zeitschrift fur Gerontologie und Geriatrie. 2020;(4):295-302
Abstract
Selenium and zinc are essential trace elements and an inadequate dietary intake has been implicated in the decline of immune and cognitive functions in aged persons and in the pathogenesis of age-related disorders. Both micronutrients are often marketed as "antioxidants" in mineral supplements; however, neither selenium nor zinc are antioxidants per se but they may exert beneficial effects as components of enzymes and other proteins that catalyze redox reactions and/or are involved in the maintenance of redox homeostasis. According to epidemiological data older individuals have an increased risk of developing deficiencies in the selenium and zinc status; however, such statistical correlations in epidemiological studies do not imply a causal association. Intervention trials are scarce and have yielded inconsistent and sometimes even adverse results. It should also be noted that the observed deficiencies in micronutrients may not necessarily be attributable to inadequate dietary intake as the absorption and distribution within the body might also be influenced by factors such as medications or interaction with other food ingredients. Thus, any dietary supplementation should be implemented with caution and persons who wish to take mineral supplements should first seek medical advice. This article discusses the role of selenium and zinc in biological antioxidant systems, summarizes findings on the supply and supplementation of aged persons with these trace elements and on the influence they may exert on aging-related health issues, such as cognitive decline and type 2 diabetes mellitus.
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Effects of Gene-Eden-VIR and Novirin on SARS-CoV: Implications for COVID-19.
Polansky, H, Lori, G
Journal of evidence-based integrative medicine. 2020;:2515690X20932523
Abstract
The coronavirus (SARS-CoV-2), which causes COVID-19, is a betacoronavirus closely related to the human severe acute respiratory syndrome (SARS)-coronavirus (SARS-CoV). The recent COVID-19 outbreak created an urgent need for treatment. To expedite the development of such treatment, pharmaceutical companies and government agencies are currently testing several existing drugs for their effect on the virus. Gene-Eden-VIR and Novirin are natural, broad-spectrum, antiviral treatments proven to be safe and effective in several clinical studies. In this article, we present evidence indicating that the 5 Gene-Eden-VIR/Novirin ingredients have anti-betacoronavirus, and specifically, anti-SARS-CoV effects. We consider this evidence as a first indication of the anti-coronavirus effects of Gene-Eden-VIR/Novirin. Next, we are planning to conduct a clinical study with users of the treatments to test the effects of Gene-Eden-VIR/Novirin on individuals at risk and those infected with the virus.
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Circulating Selenium and Cardiovascular or All-Cause Mortality in the General Population: a Meta-Analysis.
Xiang, S, Dai, Z, Man, C, Fan, Y
Biological trace element research. 2020;(1):55-62
Abstract
The association of circulating selenium level with mortality remains controversial. This meta-analysis investigated the association between elevated circulating selenium level and cardiovascular or all-cause mortality in the general population. PubMed and Embase databases (up to January 20, 2019) were searched for observational studies or post hoc analyses of randomized controlled trials that evaluated the association between elevated circulating selenium level and cardiovascular or all-cause mortality in the general population. Twelve observational studies (ten cohort and two case-control studies) with a total of 25,667 individuals were included. Comparison with the lowest and the highest circulating selenium level showed that the pooled risk ratio (RR) values of all-cause mortality and cardiovascular mortality were 1.36 (95% confidence intervals [CI] 1.18-1.58) and 1.35 (95% CI 1.13-1.62), respectively. When analyzed selenium level as a continuous variable, each standard deviation selenium increase significantly reduced 20% all-cause mortality risk. However, the lowest circulating selenium level was not associated with a high risk of coronary mortality (RR 1.43; 95% CI 0.93-2.19). This meta-analysis indicated that low circulating selenium level was associated with higher risk of cardiovascular or all-cause mortality in the general population. Low circulating selenium level did not confer significant effect on coronary death.
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Selenium in the Treatment of Graves' Hyperthyroidism and Eye Disease.
Lanzolla, G, Marinò, M, Marcocci, C
Frontiers in endocrinology. 2020;:608428
Abstract
Based on the role of oxidative stress in the pathogenesis of Graves' hyperthyroidism (GH) and Graves' Orbitopathy (GO), a therapy with the antioxidant agent selenium has been proposed and a number of studies have been performed, both in vitro and in vivo. In GH, reactive oxygen species (ROS) contribute to the thyroid and peripheral tissues damage. In GO, tissue hypoxia, as well as ROS, are involved in the typical changes that occur in fibroadipose orbital tissue and the perimysium of extraocular muscles. Antioxidants have been proposed to improve the effects of antithyroid drugs in GH patients, as well as the remodeling of orbital tissues in patients with GO. Here, we reviewed the literature on the possible beneficial effects and clinical use of selenium in the management of patients with GH and GO. A randomized clinical trial on the use of selenium in patients with mild GO provided evidence for a beneficial effect; no data are available on more severe forms of GO. Although the real effectiveness of selenium in patients with GH remains questionable, its use in the management of mild GO is generally believed to be beneficial, and selenium administration has been included in the clinical practice for the patients with mild eye disease.
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The Interaction between Dietary Selenium Intake and Genetics in Determining Cancer Risk and Outcome.
Kadkol, S, Diamond, AM
Nutrients. 2020;(8)
Abstract
There is considerable interest in the trace element selenium as a possible cancer chemopreventive dietary component, but supplementation trials have not indicated a clear benefit. Selenium is a critical component of selenium-containing proteins, or selenoproteins. Members of this protein family contain selenium in the form of selenocysteine. Selenocysteine is encoded by an in-frame UGA codon recognized as a selenocysteine codon by a regulatory element, the selenocysteine insertion sequence (SECIS), in the 3'-untranslated region of selenoprotein mRNAs. Epidemiological studies have implicated several selenoprotein genes in cancer risk or outcome based on associations between allelic variations and disease risk or mortality. These polymorphisms can be found in or near the SECIS or in the selenoprotein coding sequence. These variations both function to control protein synthesis and impact the efficiency of protein synthesis in response to the levels of available selenium. Thus, an individual's genetic makeup and nutritional intake of selenium may interact to predispose them to acquiring cancer or affect cancer progression to lethality.
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Pregnancy, thyroid, and the potential use of selenium.
Hubalewska-Dydejczyk, A, Duntas, L, Gilis-Januszewska, A
Hormones (Athens, Greece). 2020;(1):47-53
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Abstract
The management of pregnant women is a major concern of health care around the world. There is growing evidence regarding the influence of selenium (Se) on pregnancy and fetus outcomes. However, due to as yet insufficient evidence, lack of measurable markers to assess the effect of Se supplementation on the human metabolism, and Se's narrow therapeutic index, the majority of experts and the current guidelines published by several scientific societies do not recommend the use of Se in pregnancy and in women of childbearing age. Further research based on well-designed studies, including assessment of the complex interactions between different micronutrients and individual response to different doses of Se, is needed.
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Research progress on the biological activities of selenium polysaccharides.
Zhou, N, Long, H, Wang, C, Yu, L, Zhao, M, Liu, X
Food & function. 2020;(6):4834-4852
Abstract
Selenium polysaccharides are a new type of functional polysaccharide that combines inorganic selenium with polysaccharides to form an organic selenium product. Selenium polysaccharides are obtained using three different methods, have no toxicity or side effects, and are easily absorbed and utilized by the body. A number of studies have demonstrated that selenium polysaccharides possess better antioxidant, antitumour, immune regulation, hypoglycaemic, and heavy metal removal activities than that of either polysaccharides or inorganic selenium. Selenium polysaccharides have gradually become a research topic of interest for the development of functional foods and pharmaceutical products. However, further studies are required to investigate the structures and mechanisms of selenium polysaccharides. At present, reviews that focus on the bioactivities of selenium polysaccharides are lacking. The aim of this study was to summarize the selenium polysaccharide bioactivity reports from the past decades, describe the mechanisms and shortcomings of these studies, and evaluate the need for further development.
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Challenges and perspectives of selenium supplementation in Graves' disease and orbitopathy.
Bednarczuk, T, Schomburg, L
Hormones (Athens, Greece). 2020;(1):31-39
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Abstract
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.
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Developments in the study and applications of bacterial transformations of selenium species.
Ojeda, JJ, Merroun, ML, Tugarova, AV, Lampis, S, Kamnev, AA, Gardiner, PHE
Critical reviews in biotechnology. 2020;(8):1250-1264
Abstract
Microbial bio-transformations of the essential trace element selenium are now recognized to occur among a wide variety of microorganisms. These transformations are used to convert this element into its assimilated form of selenocysteine, which is at the active center of a number of key enzymes, and to produce selenium nanoparticles, quantum dots, metal selenides, and methylated selenium species that are indispensable for biotechnological and bioremediation applications. The focus of this review is to present the state-of-the-art of all aspects of the investigations into the bacterial transformations of selenium species, and to consider the characterization and biotechnological uses of these transformations and their products.
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Mini-Review on the Roles of Vitamin C, Vitamin D, and Selenium in the Immune System against COVID-19.
Bae, M, Kim, H
Molecules (Basel, Switzerland). 2020;(22)
Abstract
Low levels of micronutrients have been associated with adverse clinical outcomes during viral infections. Therefore, to maximize the nutritional defense against infections, a daily allowance of vitamins and trace elements for malnourished patients at risk of or diagnosed with coronavirus disease 2019 (COVID-19) may be beneficial. Recent studies on COVID-19 patients have shown that vitamin D and selenium deficiencies are evident in patients with acute respiratory tract infections. Vitamin D improves the physical barrier against viruses and stimulates the production of antimicrobial peptides. It may prevent cytokine storms by decreasing the production of inflammatory cytokines. Selenium enhances the function of cytotoxic effector cells. Furthermore, selenium is important for maintaining T cell maturation and functions, as well as for T cell-dependent antibody production. Vitamin C is considered an antiviral agent as it increases immunity. Administration of vitamin C increased the survival rate of COVID-19 patients by attenuating excessive activation of the immune response. Vitamin C increases antiviral cytokines and free radical formation, decreasing viral yield. It also attenuates excessive inflammatory responses and hyperactivation of immune cells. In this mini-review, the roles of vitamin C, vitamin D, and selenium in the immune system are discussed in relation to COVID-19.