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1.
Selenium as a Bioactive Micronutrient in the Human Diet and Its Cancer Chemopreventive Activity.
Radomska, D, Czarnomysy, R, Radomski, D, Bielawska, A, Bielawski, K
Nutrients. 2021;(5)
Abstract
This review answers the question of why selenium is such an important trace element in the human diet. Daily dietary intake of selenium and its content in various food products is discussed in this paper, as well as the effects of its deficiency and excess in the body. Moreover, the biological activity of selenium, which it performs mainly through selenoproteins, is discussed. These specific proteins are responsible for thyroid hormone management, fertility, the aging process, and immunity, but their key role is to maintain a redox balance in cells. Furthermore, taking into account world news and the current SARS-CoV-2 virus pandemic, the impact of selenium on the course of COVID-19 is also discussed. Another worldwide problem is the number of new cancer cases and cancer-related mortality. Thus, the last part of the article discusses the impact of selenium on cancer risk based on clinical trials (including NPC and SELECT), systematic reviews, and meta-analyses. Additionally, this review discusses the possible mechanisms of selenium action that prevent cancer development.
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2.
Therapeutic Potential of Selenium and Selenium Compounds in Cervical Cancer.
Jablonska, E, Li, Q, Reszka, E, Wieczorek, E, Tarhonska, K, Wang, T
Cancer control : journal of the Moffitt Cancer Center. 2021;:10732748211001808
Abstract
Cervical cancer is a common female cancer. It is strongly associated with human papillomavirus (HPV) infection. However, HPV infection alone is not sufficient to induce cervical cancer because its development is dependent on the coexistence of several factors that enable the virus to overcome the host immune system. These include individual genetic background, environmental factors, or diet, including dietary selenium intake. Selenium is an essential trace element with antiviral properties and has been shown to exert antitumor effects. Surprisingly, the role of selenium in cervical cancer has not been studied as intensively as in other cancers. Here, we have summarized the existing experimental data on selenium and cervical cancer. It may be helpful in evaluating the role of this nutrient in treatment of the mentioned malignancy as well as in planning further studies in this area.
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3.
Selenium Deficiency Due to Diet, Pregnancy, Severe Illness, or COVID-19-A Preventable Trigger for Autoimmune Disease.
Schomburg, L
International journal of molecular sciences. 2021;(16)
Abstract
The trace element selenium (Se) is an essential part of the human diet; moreover, increased health risks have been observed with Se deficiency. A sufficiently high Se status is a prerequisite for adequate immune response, and preventable endemic diseases are known from areas with Se deficiency. Biomarkers of Se status decline strongly in pregnancy, severe illness, or COVID-19, reaching critically low concentrations. Notably, these conditions are associated with an increased risk for autoimmune disease (AID). Positive effects on the immune system are observed with Se supplementation in pregnancy, autoimmune thyroid disease, and recovery from severe illness. However, some studies reported null results; the database is small, and randomized trials are sparse. The current need for research on the link between AID and Se deficiency is particularly obvious for rheumatoid arthritis and type 1 diabetes mellitus. Despite these gaps in knowledge, it seems timely to realize that severe Se deficiency may trigger AID in susceptible subjects. Improved dietary choices or supplemental Se are efficient ways to avoid severe Se deficiency, thereby decreasing AID risk and improving disease course. A personalized approach is needed in clinics and during therapy, while population-wide measures should be considered for areas with habitual low Se intake. Finland has been adding Se to its food chain for more than 35 years-a wise and commendable decision, according to today's knowledge. It is unfortunate that the health risks of Se deficiency are often neglected, while possible side effects of Se supplementation are exaggerated, leading to disregard for this safe and promising preventive and adjuvant treatment options. This is especially true in the follow-up situations of pregnancy, severe illness, or COVID-19, where massive Se deficiencies have developed and are associated with AID risk, long-lasting health impairments, and slow recovery.
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4.
A Mechanistic Link Between Selenium and Coronavirus Disease 2019 (COVID-19).
Khatiwada, S, Subedi, A
Current nutrition reports. 2021;(2):125-136
Abstract
PURPOSE OF REVIEW Coronavirus disease 2019 (COVID-19) is a rapidly emerging disease caused by a highly contagious virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and this disease has affected millions of people across the world and led to hundreds of thousands of deaths worldwide. Nutrition is a key factor related to this disease, and nutritional status may determine the risk and outcomes of SARS-CoV-2 infection. Selenium is one of the major trace elements required for redox functions and has significant roles in viral infections. The purpose of this review was to examine the current evidence on the role of selenium in COVID-19. We reviewed studies on selenium and COVID-19, and other relevant studies to understand how selenium status can modify the risk of SARS-CoV-2 infection, and how selenium status might affect a person post-infection. RECENT FINDINGS We found that oxidative stress is a characteristic feature of COVID-19 disease, which is linked with the immunopathological disorder observed in individuals with severe COVID-19. Selenium plays a key role in strengthening immunity, reducing oxidative stress, preventing viral infections and supporting critical illness. Moreover, selenium deficiency is related to oxidative stress and hyperinflammation seen in critical illness, and selenium deficiency is found to be associated with the severity of COVID-19 disease. Selenium supplementation at an appropriate dose may act as supportive therapy in COVID-19. Future studies in large cohorts of COVID-19 are warranted to verify the benefits of selenium supplementation for reducing risk and severity of COVID-19.
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5.
Dietary Selenium Regulates microRNAs in Metabolic Disease: Recent Progress.
Huang, X, Dong, YL, Li, T, Xiong, W, Zhang, X, Wang, PJ, Huang, JQ
Nutrients. 2021;(5)
Abstract
Selenium (Se) is an essential element for the maintenance of a healthy physiological state. However, due to environmental and dietary factors and the narrow safety range of Se, diseases caused by Se deficiency or excess have gained considerable traction in recent years. In particular, links have been identified between low Se status, cognitive decline, immune disorders, and increased mortality, whereas excess Se increases metabolic risk. Considerable evidence has suggested microRNAs (miRNAs) regulate interactions between the environment (including the diet) and genes, and play important roles in several diseases, including cancer. MiRNAs target messenger RNAs to induce changes in proteins including selenoprotein expression, ultimately generating disease. While a plethora of data exists on the epigenetic regulation of other dietary factors, nutrient Se epigenetics and especially miRNA regulated mechanisms remain unclear. Thus, this review mainly focuses on Se metabolism, pathogenic mechanisms, and miRNAs as key regulatory factors in Se-related diseases. Finally, we attempt to clarify the regulatory mechanisms underpinning Se, miRNAs, selenoproteins, and Se-related diseases.
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6.
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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7.
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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8.
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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9.
Selenium and its supplementation in cardiovascular disease--what do we know?
Benstoem, C, Goetzenich, A, Kraemer, S, Borosch, S, Manzanares, W, Hardy, G, Stoppe, C
Nutrients. 2015;(5):3094-118
Abstract
The trace element selenium is of high importance for many of the body's regulatory and metabolic functions. Balanced selenium levels are essential, whereas dysregulation can cause harm. A rapidly increasing number of studies characterizes the wide range of selenium dependent functions in the human body and elucidates the complex and multiple physiological and pathophysiological interactions of selenium and selenoproteins. For the majority of selenium dependent enzymes, several biological functions have already been identified, like regulation of the inflammatory response, antioxidant properties and the proliferation/differentiation of immune cells. Although the potential role of selenium in the development and progression of cardiovascular disease has been investigated for decades, both observational and interventional studies of selenium supplementation remain inconclusive and are considered in this review. This review covers current knowledge of the role of selenium and selenoproteins in the human body and its functional role in the cardiovascular system. The relationships between selenium intake/status and various health outcomes, in particular cardiomyopathy, myocardial ischemia/infarction and reperfusion injury are reviewed. We describe, in depth, selenium as a biomarker in coronary heart disease and highlight the significance of selenium supplementation for patients undergoing cardiac surgery.
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10.
The chronic autoimmune thyroiditis quality of life selenium trial (CATALYST): study protocol for a randomized controlled trial.
Winther, KH, Watt, T, Bjørner, JB, Cramon, P, Feldt-Rasmussen, U, Gluud, C, Gram, J, Groenvold, M, Hegedüs, L, Knudsen, N, et al
Trials. 2014;:115
Abstract
BACKGROUND Patients with chronic autoimmune thyroiditis have impaired health-related quality of life. The thyroid gland has a high selenium concentration, and specific selenoprotein enzyme families are crucial to immune function, and catalyze thyroid hormone metabolism and redox processes in thyroid cells. Previous randomized controlled trials have found that selenium supplementation decreases thyroid-disease-specific antibody levels. We hypothesize that selenium might be beneficial in the treatment of chronic autoimmune thyroiditis. METHODS/DESIGN The CATALYST trial is an investigator-initiated randomized, blinded, multicentre clinical trial of selenium supplementation versus placebo in patients with chronic autoimmune thyroiditis. INCLUSION CRITERIA age ≥18 years; serum thyroid peroxidase antibody level ≥100 IU/ml within the previous 12 months; treatment with levothyroxine and written informed consent. EXCLUSION CRITERIA previous diagnosis of toxic nodular goitre, Graves' hyperthyroidism, postpartum thyroiditis, Graves' orbitopathy; previous antithyroid drug treatment, radioiodine therapy or thyroid surgery; immune-modulatory or other medication affecting thyroid function; pregnancy, planned pregnancy or breastfeeding; allergy towards any intervention or placebo component; intake of selenium supplementation >55 μg/day; inability to read or understand Danish or lack of informed consent. The trial will include 2 × 236 participants. The experimental intervention and control groups will receive 200 μg selenium-enriched yeast or matching placebo tablets daily for 12 months. The experimental supplement will be SelenoPrecise®. The primary outcome is thyroid-related quality of life assessed by the Thyroid Patient-Reported Outcome (ThyPRO) questionnaire. Secondary outcomes include serum thyroid peroxidase antibody concentration; serum triiodothyronine/thyroxine ratio; levothyroxine dosage; adverse reactions and serious adverse reactions and events. DISCUSSION In this pragmatic trial, participating patients follow their usual treatment at their usual hospitals. In order to collect high-quality data on the clinical course and quality of life, and to minimize missing data, an elaborate trial management system has been designed. 12 months intervention duration was selected in consideration of the primary outcome, thyroid-related quality of life. TRIAL REGISTRATION ClinicalTrials.gov ID: NCT02013479.