Are there functional consequences of a reduction in selenium intake in UK subjects?

Dietary Se levels in the UK have fallen over the last 20 years and recent surveys indicate that average Se intakes are 30-40 microg/d, which is well below the current UK reference nutrient intake for adult men (75 microg/d) or women (60 microg/d). Functional consequences of this decline have not been recognised, although epidemiological data suggest it may contribute to increased risk of infections and incidence of some cancers. Previous data have indicated that biochemical changes in Se-dependent proteins occur in otherwise healthy UK subjects given small Se supplements. The current studies have focused on the effect of small Se supplements on the immune response since there is evidence of specific interactions between Se intake and viral replication, and since the potential anti-cancer effects of Se may be mediated by non-antioxidant effects of Se such as changes in immune function. Data indicate that subjects given small Se supplements (50 or 100 microg Se/d) have changes in the activity of Se-dependent enzymes and evidence of improved immune function and clearance of an administered live attenuated virus in the form of poliovirus vaccine. Responses of individual subjects to Se supplements are variable, and current work is evaluating potential explanations for this variability, including genetic variability and pre-existing Se status

Immunomodulatory effect of dietary selenium supplementation on serum antibody response and leucocytic profile of Trypanosoma brucei brucei infected rats

Effect of selenium supplementation on the immune response of Trypanosoma brucei brucei infected rats was investigated. Twenty five (25) adult male albino rats divided into five groups of five rats each were used for this study. Groups A, B and C were fed 4, 8 and 16 part per million (ppm) selenium in their feed, respectively. Groups D and E were not given selenium supplementation. The supplementation started on day 0, followed by the infection of groups A, B, C and D with T. brucei brucei on day 14 post supplementation (PS). Immune response of the rats was assessed by determining the antibody response to sheep red blood cells (SRBC) using direct haemagglutination technique and total and differential leucocyte counts. The supplementation led to significant (p < 0.05) increase in antibody response to sheep red blood cell of the supplemented groups at pre- and post infection when compared with the control. The infection however, led to decrease in antibody titre but remained higher than the pre-supplementation titre. Also, the supplementation led to increase (p < 0.05) in leucocyte counts prior to infection on day 14 PS. The increase in total leucocyte count could be attributed to increase in lymphocyte and neutrophils. The mortality record showed that all rats (100%) in the infected, not supplemented group and 2 rats (40%) died from the 16 ppm group by day 42 PS. No rat died in 4, 8 ppm and not infected, not treated groups.Key words: Selenium, antibody titre, leucocytes, trypanosomes, immunosuppression

Effects of selenium and thyroid hormone deficiency on peritoneal macrophages adhesion and occurrence of natural IGM antibodies in juvenile rats

Both selenium, as an effector and regulator of antioxidative enzymes activity, and thyroid hormones are potent immunomodulators. Besides, selenium incorporated into iodothyronine deiodinases is involved in the thyroid function and thus indirectly regulates the immune response. Studies of the mutual infl uence of selenium and thyroid hormones on the immune response are scarce, hence we analyzed the effects of an iodothyronine deiodinases blocker, propylthiouracil (PTU), and selenium defi ciency on the function of peritoneal macrophages, and titer of naturally occurring anti-sheep red blood cells (SRBC) IgM antibodies in juvenile rats. The experiment was carried out on 64 Wistar male rats allotted to 4 groups: controlselenium adequate PTU-group; selenium adequate, PTU+ group; selenium defi cient, PTU-group; and selenium defi cient, PTU+. The selenium adequate and selenium defi cient groups were fed a diet containing 0.334 and 0.031 mg Se/kg, respectively. PTU+ groups received PTU (150 mg/L) in drinking water. After 3 weeks, thyroxine (T-4), triiodothyronine (T-3), and thyroid stimulating hormone (TSH) were determined. The animals having "intermediate" concentrations of T-3 (1.56-1.69 nmol/L) and T 4 (41-50 nmol/L) were excluded from further analysis. Thus, PTU+ groups included hypothyroid animals (T-3 lt = 1.55 nmol/L; T-4 lt = 40 nmol/L), while PTU-groups included euthyroid rats (T-3 lt = 1.70 nmol/L; T-4 lt = 50 nmol/L). Both groups of selenium defi cient rats had, when compared to the control group, a signifi cantly lower activity of glutathione peroxidase GPx1 and GPx3. Neither selenium defi ciency nor PTU infl uenced the adherence of peritoneal macrophages. Selenium defi ciency signifi cantly decreased the peroxide synthesis in macrophages and signifi cantly increased the titer of anti-SRBC IgM. Hypotyroidism alone or in combination with selenium defi ciency had no infl uence on these parameters

Selenium and cellular immunity. Evidence that selenoproteins may be encoded in the +1 reading frame overlapping the human CD4, CD8, and HLA-DR genes

Selenium deficiency can lead to impaired immune function and reduced T-cell counts, as well as various specific disorders. Significantly, in ARC and AIDS patients, a progressive decline in plasma Se, paralleling T-cell loss, has been widely documented. Since evidence now suggests that there is an extremely high turnover of CD4+ T-cells in AIDS patients, with billions of new cells lost and replaced daily, any exceptional requirement for Se in lymphocytes could contribute to this progressive Se depletion. Thus, it may be significant that, over-lapping the known genes in the +1 reading frame, the mRNAs of several T-cell associated genes (CD4, CD8, HLA-DR p33) have open reading frames (ORFs) with as many as 10 in-frame UGA codons (CD4, p33), a clustering that is highly improbable by chance alone, and reminiscent of selenoprotein P, the predominant plasma form of Se. The presence of these ORFs, along with potential stem-loop RNA structures displaying consensus selenocysteine insertion sequences, AUG(N)mAAA(N)nUGR, suggests that these mRNAs may encode selenoproteins, in addition to the known T-cell glycoproteins. If so, the roles of Se in the immune system may be more diverse than previously suspected

Immune Responses to Vibrio anguillarum in Yellowtail Kingfish, Seriola lalandi, Fed Selenium Supplementation

Effects of dietary selenium (Se) on immune competence of yellowtail kingfish, Seriola lalandi, were investigated. The fish were fed one of the three experimental diets including a control diet without Se supplementation and two diets supplemented with Se from Se-yeast (Selplex®) at 2 and 4mg/kg. After feeding for 6 wk, the fish were challenged by injecting Vibrio anguillarum and observed for 2wk. Dietary Se had no effect on feed intake, feed conversion ratio, and survival over the course of 6-wk feeding; however, it significantly increased weight gain and Se content in muscle. Following the bacterial infection, the immune-stimulating effects of Se were observed in antibody, lysozyme, and bactericidal responses, and there was a corresponding increase in survival and hematocrit by Se. Under infectious condition, antioxidant capacity of fish as measured in term of resistance of red blood cells to peroxidation and glutathione peroxidase activity also increased by supplementation of Se. Liver necrosis and kidneymelano-macrophages were only seen in surviving fish fed the control diet after the challenge. Furthermore, there was evidence of myopathy in fish fed the diet without Se supplementation. This study suggests that Se, supplemented at 2 or 4mg/kg, can improve growth and health of yellowtail kingfish

Immune-Boosting Functional Foods: A Potential Remedy for Chinese Consumers Living Under Polluted Air

The deterioration of air quality in China has resulted in many people looking for remedies to counteract the impact that air pollution is perceived to be having on their health. As the importance of diet on immune health is becoming increasingly well recognised, a narrative literature review was undertaken to elucidate Chinese consumers’ acceptance of functional food products designed to help the immune system recover from pollution-driven impact and to assess their market potential. Consumers’ attitude towards immune-boosting functional foods were mainly positive, with scientific validation being important in determining the credibility of a product. This was despite the fact that the effectiveness of the functional food products currently in the market that purported to be remedies for pollution-driven impacts on the lung did not appear to be supported by scientific evidence. Numerous studies have reported functional foods could provide a wide range of benefits to immune health, including helping pollution-driven immune issues. This review highlights the market demand for effective and scientifically-proven functional food products that help Chinese consumers’ immune system recover from the impact of air pollution

IMPORTANCE OF NUTRIENTS IN COMBATING WITH COVID-19

In present scenario COVID-19 pandemic is the leading challenge across the globe. This new coronavirus disease is declared to be a global pandemic by the World Health Organization. At present, we are dependent upon lifesaving drugs/vaccines. In addition to the drugs, the essential advisories are to be followed to prevent the spread of COVID-19 like maintaining personal hygiene, physical distancing, respiratory hygiene, vaccination, healthy and balanced nutrition and strong immune system. Our immune system protects against diseases and maintains health. Good healthy nutrition increases the immunity and controls the diseases. We need to pay attention to the importance of nutrition in curing the covid 19. This can help us to understand the relation between disease and our dietary intake. A number of vitamins (A, B6, B12, folate, C, D and E) and trace elements (zinc, copper, selenium, iron) help in maintaining the human immune system and prevent the infections. Vitamin A controls dendritic cell and CD4+ T lymphocyte maturation. Vitamins B6, B12 and folate are useful for proper functioning of natural killer cells and CD8+ cytotoxic T lymphocytes. Vitamin C fights against infection and helps in phagocytosis and bacterial killing, natural killer cell activity, T lymphocyte function and antibody production. Vitamin D improves cellular immunity. Vitamin E helps in cell-mediated immune responses. Trace amount of zinc increases the proliferation of CD8+ cytotoxic T lymphocytes and provides antiviral defence. Trace elements like copper has antiviral properties. Iron is also important for maintaining the immunity. In additions to these nutrients gut micro bacterias are found to be protective against respiratory infection. In this article the role of specific nutrients in the immune system, with regard to antiviral defences have been summarised

Nutrition, HIV, and Drug Abuse: The Molecular Basis of a Unique Role for Selenium

HIV-infected injection drug users (IDUs) often suffer from serious nutritional deficiencies. This is a concern because plasma levels of micronutrients such as vitamin B12, zinc, and selenium have been correlated with mortality risk in HIV-positive populations. Injection drug use also increases lipid peroxidation and other indicators of oxidative stress, which, combined with antioxidant deficiencies, can stimulate HIV-1 replication through activation of NF-?B transcription factors, while weakening immune defenses. As detailed herein, these prooxidant stimuli can also increase the pathogenic effects of HIV-1 by another mechanism, involving viral selenoproteins. Overlapping the envelope coding region, HIV-1 encodes a truncated glutathione peroxidase (GPx) gene (see #6 in reference list). Sequence analysis and molecular modeling show that this viral GPx (vGPx) module has highly significant structural similarity to known mammalian GPx, with conservation of the catalytic triad of selenocysteine (Sec), glutamine, and tryptophan. In addition to other functions, HIV-1 vGPx may serve as a negative regulator of proviral transcription, by acting as an NF-?B inhibitor (a known property of cellular GPx). Another potential selenoprotein coding function of HIV-1 is associated with the 3' end of the nef gene, which terminates in a conserved UGA (potential Sec) codon in the context of a sequence (Cys-Sec) identical to the C-terminal redox center of thioredoxin reductase, another cellular regulator of NF-?B. Thus, in combination with known cellular mechanisms involving Se, viral selenoproteins may represent a unique mechanism by which HIV-1 monitors and exploits an essential micronutrient to optimize its replication relative to the host