Selenium (Se) deficiency among populations in Ethiopia is consistent with low concentrations of Se in soil and crops that could be addressed partly by Se-enriched fertilisers. This study examines the disease burden of Se deficiency in Ethiopia and evaluates the cost-effectiveness of Se agronomic biofortification. A disability-adjusted life years (DALY) framework was used, considering goiter, anaemia, and cognitive dysfunction among children and women. The potential efficiency of Se agronomic biofortification was calculated from baseline crop composition and response to Se fertilisers based on an application of 10 g/ha Se fertiliser under optimistic and pessimistic scenarios. The calculated cost per DALY was compared against gross domestic product (GDP; below 1–3 times national GDP) to consider as a cost-effective intervention. The existing national food basket supplies a total of 28·2 µg of Se for adults and 11·3 µg of Se for children, where the risk of inadequate dietary Se reaches 99·1 %–100 %. Cereals account for 61 % of the dietary Se supply. Human Se deficiency contributes to 0·164 million DALYs among children and women. Hence, 52 %, 43 %, and 5 % of the DALYs lost are attributed to anaemia, goiter, and cognitive dysfunction, respectively. Application of Se fertilisers to soils could avert an estimated 21·2–67·1 %, 26·6–67·5 % and 19·9–66·1 % of DALY via maize, teff and wheat at a cost of US$129·6–226·0, US$149·6–209·1 and US$99·3–181·6, respectively. Soil Se fertilisation of cereals could therefore be a cost-effective strategy to help alleviate Se deficiency in Ethiopia, with precedents in Finland.

Minerals are supplemented routinely to dairy cows during the dry period to prevent metabolic issues postpartum. However, limited information exists on the impacts of mineral supplementation on colostrum carotenoids. This study aimed to determine the effects of prepartum supplementation with three micro-nutrients; inorganic selenium (INORG), organic selenium (ORG) or rumen-protected choline (RPC) on the carotenoid content of bovine colostrum and transition milk (TM) from pasture-based dairy cows. A total of 57 (12 primiparous and 45 multiparous) Holstein-Friesian (HF) and HF × Jersey (JEX) cows were supplemented daily for 49 ± 12.9 d before calving. Colostrum samples were collected from all cows immediately postpartum and TM one to five (TM1–TM5) were collected from a sub-set of 15 cows (five per treatment group) at each consecutive milking postpartum. Carotenoid concentration was determined using ultra-high performance liquid chromatography – diode array detection (UHPLC-DAD). With the use of transmittance, the colour index and colour parameters a*, b* and L* were used to determine colour variations over this period. Prepartum supplementation did not have a significant effect on colostrum β-carotene concentration or colour. Positive correlations between β-carotene and colour parameter b* (R2 = 0.671; P < 0.001) and β-carotene and colour index (R2 = 0.560; P < 0.001) were observed. Concentrations of β-carotene were highest in colostrum (1.34 μg/g) and decreased significantly with each milking postpartum (TM5 0.31 μg/g). Breed had a significant effect on colostrum colour with JEX animals producing a greater b* colostrum than HF animals (P = 0.030). Primiparous animals produced colostrum with the weakest colour compared to second or ≥third parity animals (P = 0.042). Despite statistical increases in the b* parameter in colostrum from JEX cows and multiparous cows, β-carotene concentrations did not significantly increase suggesting that other factors may influence colostrum colour. The b* parameter may be used as an indicator for estimating carotenoid concentrations in colostrum and TM, particularly when assessed via transmittance spectroscopy.

Selenium (Se) is a mineral with several biological functions, and studies have shown that its deficiency can be linked to many complications in patients with chronic kidney disease (CKD). This study aims to systematically review the effects of Se supplementation in patients with CKD undergoing haemodialysis (HD). This systematic review was carried out according to the PRISMA statement. Clinical trials were searched in PubMed, Lilacs, Embase, Scopus and Cochrane Library databases from inception to July 2021 and updated in July 2024. The protocol was registered on PROSPERO (CRD42021231444). Two independent reviewers performed the study screening and data extraction, and the risk of bias was evaluated using the Cochrane Collaboration tool. Thirteen studies were included in this review. Only nine studies showed results on Se levels; in all, reduced Se levels were observed before supplementation. A positive effect of supplementation on plasma Se level was demonstrated. Of the ten studies analysed, six demonstrated positive effects on antioxidant and inflammatory markers. Only one study analysed immunological parameters, showing a positive impact. From two studies that analysed thyroid hormones, only one showed positive results. All studies were classified as high risk of bias. The findings suggest that Se supplementation significantly increases plasma Se levels in these patients; however, there are still not enough studies to clarify the effects of Se supplementation on the antioxidant and inflammatory markers, immune system and thyroid hormones. Further studies are needed to elucidate the effects of Se supplementation and to provide a recommendation for patients with CKD undergoing HD.

Home enteral nutrition (HEN) is a long-term, life-sustaining nutrition therapy for patients unable to consume sufficient food orally. Patients rely on a prescribed, manufactured product to provide their full nutrient requirements, although some patients may have supplementary oral intake. Prescribed enteral nutrition is used as a treatment for malnutrition, but may, in the long-term, cause poor nutrition status. This study aimed to investigate the nutrition status (energy, protein, vitamin D, and selenium) and malnutrition incidence in long-term HEN patients in the Counties Manukau region. In this cross-sectional study, 42 adults on HEN for 4+ weeks under the care of Te Whatu Ora Health New Zealand were analysed. Participants’ enteral and oral feeding regimes were tracked using patient records and five non-consecutive 24-hour recalls. Biochemical markers, body mass index (BMI), body composition (BIA), and nutrition focussed physical findings were evaluated using reference standards and the Global Leadership Initiative on Malnutrition (GLIM) malnutrition criteria(1). Independent t-tests and Mann-Whitney tests compared participants based on their enteral and supplementary oral intakes and adherence to their enteral prescription. Dependent t-tests and Wilcoxon tests evaluated nutrients contributions from various feeding methods and sources. Over half (54.7%, n = 23) relied exclusively on enteral nutrition, but 60% did not achieve their full energy prescription. Compared to requirements based on the Oxford equation and 1g/kg of body weight, energy and protein intake was low in 20% of all participants, mean intake of these participants was 1,242 ± 183 kcal and 57.5 ± 13.5 g respectively. Participants with full enteral intake had a significantly higher vitamin D intake (14.9 µg, P<0.05) than those with supplementary oral intake (11.2 µg, P<0.05). However, those with oral intake had significantly higher intake of selenium, energy, and all the macronutrients than those with sole enteral intake. Vitamin D and selenium intakes were significantly greater in participants obtaining their full prescription than those that did not. No participants had low vitamin D or selenium blood concentrations, however 40% and 38.1% respectively were high. There was a significant relationship between meeting their energy prescription and high plasma selenium. Low BMI, mid arm muscle circumference, and fat free mass index were observed in 47.5%, 40.5%, and 44.8% of participants respectively. This was not statistically significant between groups. Fat mass and waist circumference were significantly higher in participants on full enteral nutrition. According to the GLIM malnutrition criteria, 62.5% (n = 25) of all participants were malnourished. In conclusion, while HEN patients maintain good vitamin D and selenium status, energy and protein malnutrition are evident. The types of food consumed by those with oral intake may be responsible for the differences in nutritional status. Further attention to prescription adherence and nutritional balance from HEN and oral intake is necessary for this vulnerable group.

The interplay between selenoproteins, oxidative stress, and cell death pathways holds promise in unravelling novel therapeutic targets for Alzheimer’s disease (AD) in the future. Nonetheless, further comprehensive investigations are warranted to fully comprehend the precise contributions of selenoproteins in the aetiology and potential therapeutic strategies for Alzheimer’s disease. Previous work into gene expression networks in AD has included analysis of the entire transcriptome and, as of yet, has not yielded consistent insight into pathological pathways.1 Despite the comprehensive assessment of the transcriptome enabled by current technologies, one drawback of the whole transcriptome analysis is the risk of overlooking subtle yet significant variations in metabolic pathways.2 Thus, we aimed to assess gene expression of known selenoprotein and selenium-containing pathways in two different brain regions (dorsolateral prefrontal cortex (DPC) and posterior cingulate cortex (PCC)) across the AD spectrum. We used RNA sequencing data from The Rush University’s Religious Orders Study and Memory and Aging Project (ROSMAP) cohort available in the AD Knowledge Portal (https://www.synapse.org/).3 This study included data available for a total of 889 DPC and 647 PCC samples. Four pathological phenotypes were determined based on pathology (CERAD) and clinical (CDR) status: AD ([(+) pathology, (+) clinical], prodromal disease, corresponding to donors that have not received a clinical diagnosis despite the presence of pathological alterations ([(+) pathology, (−) clinical], controls ([(−) pathology, (−) clinical] and non-AD dementia [(+) pathology, (+) clinical]. This last group was excluded from the analysis as it is assumed they may have been misdiagnosed or presented with non-AD dementia. Six selenium or AD-related pathways were assessed, accounting for 421 unique genes. Group comparisons were performed using linear mixed modelling adjusted for age, sex, APOEe4 status and batch via DESeq2 package with Benjamini-Hochberg adjustment for multiple testing. A total of 18 genes significantly differed between AD and controls in both brain areas (same direction in both brain areas; P < 0.05), including eight selenoprotein genes or genes directly associated with selenoprotein synthesis. Fifteen of them were also different (same direction) in PCC (seven selenoprotein/selenoprotein synthesis genes), and four were different in DPC (four selenoprotein/selenoprotein synthesis genes) between AD and prodromal. Only three genes significantly differed between prodromal and control samples (DPC), including the selenoprotein DIO3 and the transcription factor SP3. Our findings indicate a progressive change in gene expression across the different stages of AD. These findings shed light on critical genes involved in selenoprotein synthesis that play a role in AD pathogenesis. Restricting the analysis to a subset of pathways enabled the detection of smaller alterations between groups, which is particularly appropriate in trace element homeostasis, where small alterations may have significant downstream effects.

The importance of Se in human health has received much attention due to its antioxidant properties when it is consumed at an appropriate level. However, the existing evidence is limited to obtain an effective conclusion for colorectal cancer (CRC). Notably, an adequate intake of Se was reported for Koreans. Furthermore, cytokine secretion and immune function may be affected by dietary Se. Our study aimed to explore whether Se potentially reduces CRC risk and whether the IL10 rs1800871 polymorphism has an effect on this association. We designed a case–control study with 1420 cases and 2840 controls. A semi-quantitative FFQ was used to obtain information on Se intake. We determined IL10 rs1800871 through genetic analysis. Different models were developed to explore Se intake related to CRC risk by calculating OR and 95 % CI using unconditional logistic regression. A reduced risk of CRC was found as Se intake increased, with an OR (95 % CI) of 0·44 (0·35, 0·55) (Pfor trend < 0·001). However, this association seems to be allele-specific and only present among risk variant allele carriers (GA/GG) with a significant interaction between dietary Se and IL10 rs1800871 (Pfor interaction = 0·043). We emphasised that a reduction in CRC risk is associated with appropriate Se intake. However, the IL10 rs1800871 polymorphism has an impact on this reduction, with a greater effect on variant allele carriers. These findings suggest the importance of considering an individual’s genetic characteristics when developing nutritional strategies for CRC prevention.

Selenium is an essential mineral yet both deficiency and excess are associated with adverse health effects. Dietary intake of Se in humans varies greatly between populations due to food availability, dietary preferences, and local geological and ecosystem processes impacting Se accumulation into agricultural products and animal populations. We argue there is a need to evaluate and reconsider the relevance of public health recommendations on Se given recent evidence, including the metabolic pathways and health implications of Se. This argument is particularly pertinent for Inuit populations in Northern Canada, who often exceed dietary tolerable upper intake levels and exhibit very high whole blood Se concentrations due to their dependence on local country foods high in the newly discovered Se compound, selenoneine. Since selenoneine appears to have lower toxicity compared to other Se species and does not contribute to the circulating pools of Se for selenoprotein synthesis, we argue that total dietary Se or total Se in plasma or whole blood are poor indicators of Se adequacy for human health in these populations. Overall, this review provides an overview of the current evidence of Se speciation, deficiency, adequacy, and excess and implications for human health and dietary recommendations, with particular reference to Inuit populations in the Canadian Arctic and other coastal populations consuming marine foods.

There is a dearth of data on Se status in very old adults. The aims of this study were to assess Se status and its determinants in 85-year-olds living in the Northeast of England by measuring serum Se and selenoprotein P (SELENOP) concentrations and glutathione peroxidase 3 (GPx3) activity. A secondary aim was to examine the interrelationships between each of the biomarkers. In total, 757 participants (463 women, 293 men) from the Newcastle 85+ Study were included. Biomarker concentrations were compared with selected cut-offs (serum Se: suboptimal 70 µg/l and deficient 45 µg/l; SELENOP: suboptimal 4·5 mg/l and deficient 2·6 mg/l). Determinants were assessed using linear regressions, and interrelationships were assessed using restricted cubic splines. Median (inter-quartile range) concentrations of serum Se, SELENOP and of GPx3 activity were 53·6 (23·6) µg/l, 2·9 (1·9) mg/l and 142·1 (50·7) U/l, respectively. Eighty-two percentage and 83 % of participants had suboptimal serum Se (< 70 µg/l) and SELENOP (< 4·5 mg/l), and 31 % and 40 % of participants had deficient serum Se (< 45 µg/l) and SELENOP (< 2·6 mg/l), respectively. Protein intake was a significant determinant of Se status. Additional determinants of serum Se were sex, waist:hip ratio, self-rated health and disease, while sex, BMI and physical activity were determinants of GPx3 activity. There was a linear association between serum Se and SELENOP, and nonlinear associations between serum Se and GPx3 activity and between SELENOP and GPx3 activity. These findings indicate that most participants had suboptimal Se status to saturate circulating SELENOP.

Cotype material of stibiogoldfieldite from the Mohawk mine, Goldfield, Nevada, USA, has been examined in order to collect single-crystal X-ray diffraction data of Te-rich stibiogoldfieldite and to characterise the associated Ag–Bi–(S,Se) phase. Tellurium-rich stibiogoldfieldite, with empirical formula (Cu11.30Ag0.03)Σ11.33(Sb0.80As0.57Bi0.06Te2.57)Σ4.00(S12.83Se0.20)Σ13.03, is cubic, space group I$\bar{4}$3m, with unit-cell parameters a = 10.2947(3) Å and V = 1091.04(10) Å3. Its crystal structure has been refined to R1 = 0.0161 for 397 unique reflections with Fo > 4σ(Fo) and 25 refined parameters. The structure refinement confirmed the occurrence of a vacancy at the M(2) site, in agreement with the substitution M(2)Cu+ + X(3)(Sb/As)3+ = M(2)□ + X(3)Te4+. The Ag–Bi–(S,Se) phase was identified as the 6P homologue of the pavonite series, namely dantopaite. Its empirical formula is Cu1.36Ag4.39Pb0.12Bi12.62Sb0.06(S14.01Se7.91Te0.08), showing an exceptionally high Se content. Unit-cell parameters of Se-bearing dantopaite are a = 13.518(2), b = 4.0898(6), c = 18.984(3) Å, β = 106.816(6)°, V = 1004.7(3) Å3 and space group C2/m. The crystal structure was refined to R1 = 0.0504 for 1230 unique reflections with Fo > 4σ(Fo) and 82 refined parameters. The metal excess (~0.55 atoms per formula unit) of this pavonite homologue is mainly due to the accumulation of Ag and Cu in the thin slab of the crystal structure, whereas the high Se content is related to the partial replacement of S occurring preferentially in the thick PbS-like slab. Domains richer in Se and Pb in dantopaite, with empirical formula Cu0.89Ag4.50Pb0.49Bi12.53Sb0.07(S11.26Se10.74), were also identified, as grains up to 30 μm in size intimately intergrown with bohdanowiczite, indicating the possibility of a wide Se-to-S substitution in dantopaite.

The nutritional status is a determinant of the immune response that promotes a cellular homeostasis. In particular, adequate selenium levels lead to a better antioxidant and immune response. The aim of this work is to assess whether blood selenium levels, at time of SARS-CoV-2 infection, have an impact on the development and severity of COVID-19. A systematic review and meta-analysis of comparative and descriptive studies using MeSH terms, selenium and COVID-19 was performed. We searched bibliographic databases up to 17 July 2022 in PubMed and ScienceDirect. Studies that reported data on blood selenium levels were considered. A total of 629 articles were examined by abstract and title, of which 595 abstracts were read, of which 38 were included in the systematic review and 11 in the meta-analysis. Meta-analysis was conducted to mean difference (MD) with a 95 % confidence interval (CI), and heterogeneity was tested by I2 with random factors with a MD between selenium levels, mortality, morbidity and healthy subjects with a P-value of 0⋅05. Selenium levels were higher in healthy people compared to those in patients with COVID-19 disease (six studies, random effects MD: test for overall effect Z = 3⋅28 (P = 0⋅001), 97 % CI 28⋅36 (11⋅41–45⋅31), P < 0⋅00001), but without difference when compared with the degree of severity in mild, moderate or severe cases. In conclusion, the patients with active SARS-CoV-2 infection had lower selenium levels than the healthy population. More studies are needed to evaluate its impact on clinical severity through randomised clinical trials.

Anaemia is characterised by low hemoglobin (Hb) concentration. Despite being a public health concern in Ethiopia, the role of micronutrients and non-nutritional factors as a determinant of Hb concentrations has been inadequately explored. This study focused on the assessment of serum micronutrient and Hb concentrations and a range of non-nutritional factors, to evaluate their associations with the risk of anaemia among the Ethiopian population (n 2046). It also explored the mediation effect of Zn on the relation between se and Hb. Bivariate and multivariate regression analyses were performed to identify the relationship between serum micronutrients concentration, inflammation biomarkers, nutritional status, presence of parasitic infection and socio-demographic factors with Hb concentration (n 2046). Sobel–Goodman test was applied to investigate the mediation of Zn on relations between serum se and Hb. In total, 18·6 % of participants were anaemic, 5·8 % had iron deficiency (ID), 2·6 % had ID anaemia and 0·6 % had tissue ID. Younger age, household head illiteracy and low serum concentrations of ferritin, Co, Cu and folate were associated with anaemia. Serum se had an indirect effect that was mediated by Zn, with a significant effect of se on Zn (P < 0·001) and Zn on Hb (P < 0·001). The findings of this study suggest the need for designing a multi-sectorial intervention to address anaemia based on demographic group.

Se deficiency causes impaired growth of fish skeletal muscle due to the retarded hypertrophy of muscle fibres. However, the inner mechanisms remain unclear. According to our previous researches, we infer this phenomenon is associated with Se deficiency-induced high concentration of reactive oxygen species (ROS), which could suppress the target of rapamycin complex 1 (TORC1) pathway-mediated protein synthesis by inhibiting protein kinase B (Akt), an upstream protein of TORC1. To test this hypothesis, juvenile zebrafish (45 d post-fertilisation) were fed a basal Se-adequate diet or a basal Se-deficient diet or them supplemented with an antioxidant (DL-α-tocopherol acetate, designed as VE) or a TOR activator (MHY1485) for 30 d. Zebrafish fed Se-deficient diets exhibited a clear Se-deficient status in skeletal muscle, which was not influenced by dietary VE and MHY1485. Se deficiency significantly elevated ROS concentrations, inhibited Akt activity and TORC1 pathway, suppressed protein synthesis in skeletal muscle, and impaired hypertrophy of skeletal muscle fibres. However, these negative effects of Se deficiency were partly (except that on ROS concentration) alleviated by dietary MHY1485 and completely alleviated by dietary VE. These data strongly support our speculation that Se deficiency-induced high concentration of ROS exerts a clear inhibiting effect on TORC1 pathway-mediated protein synthesis by regulating Akt activity, thereby restricting the hypertrophy of skeletal muscle fibres in fish. Our findings provide a mechanistic explanation for Se deficiency-caused retardation of fish skeletal muscle growth, contributing to a better understanding of the nutritional necessity and regulatory mechanisms of Se in fish muscle physiology.

Cognitive decline occurs commonly as people age. Despite the complexity of cellular mechanisms, oxidative stress is a critical contributor to age-associated cognitive impairment. Selenium plays an important role in antioxidant defense systems. The purpose of the present study was to assess the correlation between selenium intake and cognitive function among older adults. The participants were individuals ≥65 years old (n=1681) who participated in the 2011–2014 National Health and Nutrition Examination Survey (NHANES), a country-wide cross-sectional survey. Dietary selenium intake and adequacy were evaluated with 2 d of 24-h recalls and the estimated average requirement (EAR) cut-point method, respectively. Cognitive function was assessed with the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) score, which was significantly higher when selenium intake was adequate. After adjusting for energy intake, the association was no longer significant. Inadequate intake of selenium is rare in the US and dependent on caloric intake in older adults.

Deficiency of essential trace element, Se, has been implicated in adverse birth outcomes and in child linear growth because of its important role in redox biology and associated antioxidant effects. We used data from a randomised controlled trial conducted among a cohort of pregnant and lactating women in Dhaka, Bangladesh to examine associations between Se biomarkers in whole blood (WBSe), serum and selenoprotein P (SEPP1) in maternal delivery and venous cord (VC) blood. Associations between Se biomarkers, birth weight and infant growth outcomes (age-adjusted length, weight, head circumference and weight-for-length z-scores) at birth, 1 and 2 years of age were examined using regression analyses. WB and serum Se were negatively associated with birth weight (adjusted β, 95 % CI, WBSe delivery: −26·6 (–44·3, −8·9); WBSe VC: −19·6 (–33·0, −6·1)); however, delivery SEPP1 levels (adjusted β: −37·5 (–73·0, −2·0)) and VC blood (adjusted β: 82·3 (30·0, 134·7)) showed inconsistent and opposite associations with birth weight. Positive associations for SEPP1 VC suggest preferential transfer from mother to fetus. We found small associations between infant growth and WBSe VC (length-for-age z-score β, 95 % CI, at birth: −0·05 (–0·1, −0·01)); 12 months (β: −0·05 (–0·08, −0·007)). Weight-for-age z-score also showed weak negative associations with delivery WBSe (at birth: −0·07 (–0·1, −0·02); 12 -months: −0·05 (–0·1, −0·005)) and in WBSe VC (at birth: −0·05 (–0·08, −0·02); 12 months: −0·05 (–0·09, −0·004)). Given the fine balance between essential nutritional and toxic properties of Se, it is possible that WB and serum Se may negatively impact growth outcomes, both in utero and postpartum.

Approximately one-in-ten reproductive age adults in the USA follow a plant-based diet, yet there is limited information on the influence of vegan and vegetarian diets on the mineral composition of breast milk. This study explored the major and trace mineral composition in breast milk and associations with maternal diet patterns. We used a cross-sectional design to collect a single sample of breast milk from individuals following vegan (n 23), vegetarian (n 19) and omnivore (n 21) diet patterns. Plant-based diet (n 42) was defined as following either vegan or vegetarian diets. Sixteen minerals were assessed using inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry. Data were evaluated using traditional statistical techniques and five different machine learning approaches. The distribution of Se (median; quartile 1 and 3) was significantly different between groups (vegetarians 21, 18–26 µg/l; vegans 19, 18–25 µg/l and omnivores 17, 14–20 µg/l; P = 0·007) using a Kruskal–Wallis test. Machine learning techniques also identified Se as a potential biomarker for differentiating breast milk by maternal diet pattern. Individuals following a plant-based diet generally had a lower BMI, higher breast milk Se and lower breast milk I and Fe concentrations compared with those following omnivore diets. This suggests that maternal dietary pattern (plant-based v. omnivore) may be helpful clinical information to consider when caring for the breast-feeding dyad, with the strongest evidence related to differences in Se concentration.

Selenium (Se) is essential for selenoprotein synthesis, being thus important for immune and thyroid function, and for antioxidant defence. Some studies have shown that low levels of Se may associate with hypertensive disorders of pregnancy (HDP). Nevertheless, evidence supporting Se supplementation in pregnant or childbearing-age women is still lacking. In this context, this work aimed to systematically review the most recent scientific evidence to understand the relationship between Se levels and HDP. We performed a systematic review (protocol number: CRD42022310424) with literature of the last decade. PubMed, Scopus, Web of Science, registers and grey literature were searched to identify studies reporting measurement of Se levels in normotensive and hypertensive pregnant women (supplemented or not with Se). Study quality was assessed using the National Heart, Lung, and Blood Institute Study Quality Assessment Tools. Among the thirty included studies, a majority, 61 % (n 19) of the ‘good’ or ‘fair’ studies, reported a negative association between Se and HDP, and some studies, 39 % (n 11) of the ‘good’ or ‘fair’ studies, reported a lack of association. This review provides an important amount of quality evidence suggesting that low Se levels associate with the occurrence of HDP. Nevertheless, the gathered information is not enough to underlie a recommendation for Se supplementation in pregnancy to protect against HDP. Thus, this review emphasises the need for further well-designed randomised controlled trials that may provide blunt evidence regarding the benefits of Se supplementation during pregnancy.

Selenium is found at the active centre of twenty-five selenoproteins which have a variety of roles, including the well-characterised function of antioxidant defense, but it also is claimed to be involved in the immune system. However, due to limited and conflicting data for different parameters of immune function, intakes of selenium that have an influence on immune function are uncertain. This review covers the relationship between selenium and immune function in man, focusing on the highest level of evidence, namely that generated by randomised controlled trials (RCT), in which the effect of selective administration of selenium, in foods or a supplement, on immune function was assessed. A total of nine RCT were identified from a systematic search of the literature, and some of these trials reported effects on T and natural killer cells, which were dependent on the dose and form of selenium administered, but little effect of selenium on humoral immunity. There is clearly a need to undertake dose–response analysis of cellular immunity data in order to derive quantitative relationships between selenium intake and measures of immune function. Overall, limited effects on immunity emerged from experimental studies in human subjects, though additional investigation on the potential influence of selenium status on cellular immunity appears to be warranted.

In this review, the relevance of selenium (Se) to viral disease will be discussed paying particular attention to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease (COVID-19). Se, the active centre in selenoproteins has an ongoing history of reducing the incidence and severity of viral infections. Host Se deficiency increased the virulence of RNA viruses such as influenza A and coxsackievirus B3, the latter of which is implicated in the development of Keshan disease in north-east China. Significant clinical benefits of Se supplementation have been demonstrated in HIV-1, in liver cancer linked to hepatitis B, and in Chinese patients with hantavirus that was successfully treated with oral sodium selenite. China is of particular interest because it has populations that have both the lowest and the highest Se status in the world. We found a significant association between COVID-19 cure rate and background Se status in Chinese cities; the cure rate continued to rise beyond the Se intake required to optimise selenoproteins, suggesting an additional mechanism. Se status was significantly higher in serum samples from surviving than non-surviving COVID-19 patients. As regards mechanism, SARS-CoV-2 may interfere with the human selenoprotein system; selenoproteins are important in scavenging reactive oxygen species, controlling immunity, reducing inflammation, ferroptosis and endoplasmic reticulum (ER) stress. We found that SARS-CoV-2 significantly suppressed mRNA expression of GPX4, of the ER selenoproteins, SELENOF, SELENOM, SELENOK and SELENOS and down-regulated TXNRD3. Based on the available data, both selenoproteins and redox-active Se species (mimicking ebselen, an inhibitor of the main SARS-CoV-2 protease that enables viral maturation within the host) could employ their separate mechanisms to attenuate virus-triggered oxidative stress, excessive inflammatory responses and immune-system dysfunction, thus improving the outcome of SARS-CoV-2 infection.

Trichinosis is a serious zoonotic disease that causes human morbidity and mortality. New effective natural remedies with minimal side effects that are well tolerated are needed to treat both enteral and parenteral trichinosis. This study evaluated the efficacy of selenium (Se), Se nanoparticles (SeNPs) and Egyptian propolis compared with albendazole as antiparasitic, anti-inflammatory and anti-angiogenic agents for treating murine trichinosis. We used parasitological, histopathological and immunohistochemical assays, as well as scanning electron microscopy, to examine adult worms. Overall, 80 Swiss albino male mice were divided into eight groups, with ten mice in each group, as follows: negative control, positive control, albendazole, propolis, Se, combination of propolis and Se, SeNPs and combination of SeNPs and propolis. Mice were slaughtered seven and 35 days after infection to examine the intestinal and muscular phases, respectively. This study demonstrated the efficacy of the combination of SeNPs and propolis. As revealed by electron microscopy, this combination caused damage to the adult worm cuticle. Additionally, compared with albendazole, it resulted in a significant reduction in adult worm and total larval counts; moreover, it caused a decrease in the number of larvae deposited in muscles, with a highly significant decrease in the inflammatory cell infiltrate around the larvae and a considerable decrease in the expression of the angiogenic marker vascular endothelial growth factor in muscles. In conclusion, the combination of SeNPs and propolis had antiparasitic, anti-inflammatory and anti-angiogenic effects on trichinosis. Consequently, this combination could be used as a natural alternative therapy to albendazole for treating trichinosis.