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1.
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.
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2.
Selenium: A sole treatment for erosive oral lichen planus (Randomized controlled clinical trial).
Qataya, PO, Elsayed, NM, Elguindy, NM, Ahmed Hafiz, M, Samy, WM
Oral diseases. 2020;(4):789-804
Abstract
Oral lichen planus (OLP) is a chronic disease with immune-mediated pathogenesis. Selenium (Se), an antioxidant, plays a role in modulating immunity. The aim of this clinical trial was to evaluate two Se forms (novel topical hydrogel and oral capsules), solely, in treating erosive OLP based on clinical evaluation and salivary oxidative stress markers. Patients were allocated into one of three groups: group I, topical corticosteroids; group II, topical Se; and group III, systemic Se. Treatment lasted for 6 weeks; patients were clinically evaluated at baseline, 6, and 12 weeks. Biochemical analysis for salivary malondialdehyde (MDA) and total antioxidant capacity (TAC) levels at baseline and 6 weeks was performed. There was a significant reduction in signs and symptoms in response to all treatment modalities. However, there was no significant difference among the three groups at 6 weeks. At 12 weeks, group II had significantly lower pain scores compared with group I. Salivary MDA levels showed a significant decrease in patients of group I and group III. TAC levels showed no significant difference in response to treatment. Selenium can be proposed as a treatment for OLP. Salivary MDA levels can be a biomarker for OLP disease severity.
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3.
[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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4.
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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5.
Multiple nutritional factors and thyroid disease, with particular reference to autoimmune thyroid disease.
Rayman, MP
The Proceedings of the Nutrition Society. 2019;(1):34-44
Abstract
Hashimoto's thyroiditis (HT) and Graves' disease (GD) are examples of autoimmune thyroid disease (AITD), the commonest autoimmune condition. Antibodies to thyroid peroxidase (TPO), the enzyme that catalyses thyroid-hormone production and antibodies to the receptor for the thyroid-stimulating hormone, are characteristic of HT and GD, respectively. It is presently accepted that genetic susceptibility, environmental factors, including nutritional factors and immune disorders contribute to the development of AITD. Aiming to investigate the effect of iodine, iron and selenium in the risk, pathogenesis and treatment of thyroid disease, PubMed and the Cochrane Library were searched for relevant publications to provide a narrative review. Iodine: chronic exposure to excess iodine intake induces autoimmune thyroiditis, partly because highly-iodinated thyroglobulin (Tg) is more immunogenic. The recent introduction of universal salt iodisation can have a similar, although transient, effect. Iron: iron deficiency impairs thyroid metabolism. TPO is a haem enzyme that becomes active only after binding haem. AITD patients are frequently iron-deficient since autoimmune gastritis, which reduces iron absorption and coeliac disease which causes iron loss, are frequent co-morbidities. In two-thirds of women with persistent symptoms of hypothyroidism despite appropriate levothyroxine therapy, restoration of serum ferritin above 100 µg/l ameliorated symptoms. Selenium: selenoproteins are essential to thyroid action. In particular, the glutathione peroxidases remove excessive hydrogen peroxide produced there for the iodination of Tg to form thyroid hormones. There is evidence from observational studies and randomised controlled trials that selenium, probably as selenoproteins, can reduce TPO-antibody concentration, hypothyroidism and postpartum thyroiditis. Appropriate status of iodine, iron and selenium is crucial to thyroid health.
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6.
Role of selenium supplementation in prevention of late onset sepsis among very low birth weight neonates: a systematic review of randomized controlled trials.
Garg, BD, Bansal, A, Kabra, NS
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2019;(24):4159-4165
Abstract
Background: Neonatal sepsis is one of the most common causes of neonatal morbidity and mortality. Selenium has antioxidant and immune-modulating properties.Aim: The aim of this systematic review is to evaluate role of selenium supplementation in the prevention of late onset sepsis (LOS) among very low birth weight (VLBW) neonates.Methods: We searched literature for this review by searching the Cochrane Central Register of Controlled Trials (CENTRAL) electronic PubMed, Embase, and Google Scholar. We also searched for ongoing clinical trials.Results: This review included two randomized controlled trials (RCTs) that fulfilled inclusion criteria. There was statistically significant reduction in the incidence of LOS in the intervention group [23.7 versus 35.6%; relative risk (RR) 0.67; 95% CI 0.52-0.86; p= .001; number needed to treat (NNT) 8.4; 95% CI 5.2-20.96]. However, mortality due to any cause prior to hospital discharge was not statistically significant in between the groups (6.1% intervention group versus 6.9% control group; RR 0.88; 95% CI 0.49-1.61; p= .68).Conclusions: Evidences from current systematic review revealed that selenium supplementation has some role in the prevention of LOS. However, due to limited evidences and heterogeneity between studies, large RCTs are recommended among VLBW neonates.
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7.
The Link Between Selenium, Oxidative Stress and Pregnancy Induced Hypertensive Disorders.
Bizerea, TO, Dezsi, SG, Marginean, O, Stroescu, R, Rogobete, A, Bizerea-Spiridon, O, Ilie, C
Clinical laboratory. 2018;(10):1593-1610
Abstract
BACKGROUND The first line of defence against oxidative stress (OS) are the endogenous antioxidants, such as the Se containing compounds. During pregnancy, OS is caused by the intense growth activity of the fetus; therefore, the placenta is a key place for the activity of many seleno-compounds such as glutathione-peroxidase and thioredoxinreductase. METHODS This review aims to establish the link between the type of selenium compounds, their concentration, their metabolic pathways, and their role in both physiologic and pathologic processes during pregnancy. RESULTS A review of current literature establishes that Se containing compounds have a strong antioxidant effect. The limits that define deviations from the normal concentration range of selenium are very close. Both selenium deficiency and excess have an effect on human health. It is well known that oxidative stress, namely the increase in the concentration of reactive species of oxygen and nitrogen (ROS and RNS) and the disruption of cellular redox homeostasis, are responsible for a number of inflammatory, degenerative, autoimmune, and neoplastic diseases. Selenium deficiency in the pregnant woman's body is considered a risk factor for immune deficiency, PIH, spontaneous abortions, and premature birth. In regard to the fetus, while there seems to be a certain protection against selenium-induced toxicity, studies have shown that selenium defficiency leads to IUGR and SGA newborns. Also, combined deficiency of selenium and iodine has been linked to endemic cretinism in newborns. CONCLUSIONS The antioxidant role that selenium performs through selenoproteins is major. Selenium-containing proteins, especially glutathione peroxidase, as antioxidant enzymes, are involved in regulating the ROS and RNS levels and redox balancing in almost all tissues. Among the multiple benefits of selenium in optimal concentrations in the body are stimulation and support of female fertility, as well as good development of the fetus. Hypertensive pathologies that occur in one of ten pregnant women, especially during the second part of the gestation period, are largely due to selenium deficiency.
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8.
Myo-inositol and selenium reduce the risk of developing overt hypothyroidism in patients with autoimmune thyroiditis.
Ferrari, SM, Fallahi, P, Di Bari, F, Vita, R, Benvenga, S, Antonelli, A
European review for medical and pharmacological sciences. 2017;(2 Suppl):36-42
Abstract
OBJECTIVE The beneficial effects obtained by myo-inositol in association with seleno-methionine in patients affected by subclinical hypothyroidism have been recently demonstrated. Here, we evaluate the immune-modulating effect of myo-inositol in association with seleno-methionine in patients with euthyroid autoimmune thyroiditis (AT). PATIENTS AND METHODS Twenty-one consecutive Caucasian patients with newly diagnosed euthyroid chronic AT were evaluated. All subjects were treated with myo-inositol in association with selenium (600 mg/83 mg) tablets, twice per day, for six months. A complete thyroid assessment was done before the treatment, and after six months. RESULTS After the treatment thyroid-stimulating hormone (TSH) levels significantly declined with respect to basal values, overall in patients with an initial TSH value in the high normal range (2.1 CONCLUSIONS We first show an immune-modulatory effect of myo-inositol in association with seleno-methionine in patients with euthyroid AT. Further studies are needed to extend the observations in a large population, to evaluate the effect on the quality of life, and to study the mechanism of the effect on chemokines.
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9.
A short-term intervention with selenium affects expression of genes implicated in the epithelial-to-mesenchymal transition in the prostate.
Kok, DE, Kiemeney, LA, Verhaegh, GW, Schalken, JA, van Lin, EN, Sedelaar, JP, Witjes, JA, Hulsbergen-van de Kaa, CA, van 't Veer, P, Kampman, E, et al
Oncotarget. 2017;(6):10565-10579
Abstract
In parallel with the inconsistency in observational studies and chemoprevention trials, the mechanisms by which selenium affects prostate cancer risk have not been elucidated. We conducted a randomized, placebo-controlled trial to examine the effects of a short-term intervention with selenium on gene expression in non-malignant prostate tissue. Twenty-three men received 300 µg selenium per day in the form of selenized yeast (n=12) or a placebo (n=11) during 5 weeks. Prostate biopsies collected from the transition zone before and after intervention were analysed for 15 participants (n=8 selenium, n=7 placebo). Pathway analyses revealed that the intervention with selenium was associated with down-regulated expression of genes involved in cellular migration, invasion, remodeling and immune responses. Specifically, expression of well-established epithelial markers, such as E-cadherin and epithelial cell adhesion molecule EPCAM, was up-regulated, while the mesenchymal markers vimentin and fibronectin were down-regulated after intervention with selenium. This implies an inhibitory effect of selenium on the epithelial-to-mesenchymal transition (EMT). Moreover, selenium was associated with down-regulated expression of genes involved in wound healing and inflammation; processes which are both related to EMT. In conclusion, our explorative data showed that selenium affected expression of genes implicated in EMT in the transition zone of the prostate.
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10.
The effect of selenium supplementation on coronary heart disease: A systematic review and meta-analysis of randomized controlled trials.
Ju, W, Li, X, Li, Z, Wu, GR, Fu, XF, Yang, XM, Zhang, XQ, Gao, XB
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 2017;:8-16
Abstract
BACKGROUND Selenium is a crucial mineral with antioxidant and immune functions, and selenium deficiency may increase the risk of coronary heart disease (CHD). However, the effect of selenium supplementation on CHD is still controversial according to numerous randomized controlled trials (RCTs). The aim of our meta-analysis study was to investigate the impact of selenium on CHD. METHODS PUBMED, EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials databases were systematically searched to identify RCTs evaluating the effect of selenium supplementation on CHD mortality, blood lipid profile (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total cholesterol), serum C-reactive protein (CRP), and the level of glutathione peroxidase (GSH-PX) from inception until September 20, 2016. Odds ratio of CHD mortality and the associated 95% confidence intervals (CIs) were calculated using the fixed effect model. Weighted mean difference or standardized mean difference (SMD) and 95% confidence intervals (CIs) were calculated to determine the lipid profile, serum CRP, and GSH-PX using fixed effect or random effect models depending on the observed heterogeneity. RESULTS A total of 16 eligible RCTs with 43998 participants were included. Significant effects were observed for serum CRP (SMD=-0.48; 95% CI, -0.96 to 0; p=0.049) and GSH-PX (SMD=0.5; 95% CI, 0.36-0.64; p<0.001) after selenium supplementation. However, selenium supplementation was not statistically associated with CHD mortality and an aberrant lipid profile. CONCLUSION Selenium supplementation decreased serum CRP and increased the GSH-PX level, suggesting a positive effect on reducing oxidative stress and inflammation in CHD. However, selenium supplementation is not sufficient to reduce mortality and to improve the lipid status.