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Selenium and human health

Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
The Lancet (Impact Factor: 45.22). 02/2012; 379(9822):1256-68. DOI: 10.1016/S0140-6736(11)61452-9
Source: PubMed

ABSTRACT Selenium is incorporated into selenoproteins that have a wide range of pleiotropic effects, ranging from antioxidant and anti-inflammatory effects to the production of active thyroid hormone. In the past 10 years, the discovery of disease-associated polymorphisms in selenoprotein genes has drawn attention to the relevance of selenoproteins to health. Low selenium status has been associated with increased risk of mortality, poor immune function, and cognitive decline. Higher selenium status or selenium supplementation has antiviral effects, is essential for successful male and female reproduction, and reduces the risk of autoimmune thyroid disease. Prospective studies have generally shown some benefit of higher selenium status on the risk of prostate, lung, colorectal, and bladder cancers, but findings from trials have been mixed, which probably emphasises the fact that supplementation will confer benefit only if intake of a nutrient is inadequate. Supplementation of people who already have adequate intake with additional selenium might increase their risk of type-2 diabetes. The crucial factor that needs to be emphasised with regard to the health effects of selenium is the inextricable U-shaped link with status; whereas additional selenium intake may benefit people with low status, those with adequate-to-high status might be affected adversely and should not take selenium supplements.

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    • "Another set of sensitivity analyses was undertaken to focus on groups which may represent individuals with higher risk (those reporting taking a cholesterol lowering medication) or lower risk (those with selenium levels in a range previously identified as being associated with lowest mortality) of cardiovascular disease. Finally, an attempt was made to identify participants with serum selenium o122 μg/L, the level which delineated negative and positive risk for certain outcomes (cancer, non-melanoma skin cancer, type II diabetes mellitus) in the Nutritional Prevention of Cancer study (reviewed in (Rayman, 2012)). However, only 2 (unweighted) NHANES participants had serum selenium in this range, thus analysis of associations with lipids was not possible. "
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    ABSTRACT: Selenium is an essential micronutrient, and due to its antioxidant activity, is hypothesized to be beneficial to cardiovascular health. However, the evidence for an association between selenium and health markers such as lipid levels has been mixed. This may be due to substantial variability in the level of selenium intake between populations and potential non-linearity of selenium-health outcome associations. We used the 2011-2012 National Health and Nutrition Examination Survey (NHANES) to examine the relationship between serum selenium and lipid levels among participants aged 12 years and older. Associations were evaluated using both linear regression models, as well as ordinal logistic regression and quantile regression models to allow for potential non-linear relationships. In all models, potential confounders of sex, age group, race/ethnicity, educational attainment and cotinine were included. Overall, 40% of participants had total cholesterol levels classified as borderline or elevated, and total cholesterol increased with increasing selenium (p=0.01). A similar pattern was seen for triglycerides (p=0.02). LDL cholesterol was also associated with selenium but not in a linear fashion; HDL cholesterol did not vary with selenium. Multivariate quantile regression showed significant associations between selenium and total cholesterol, LDL cholesterol, and triglycerides. The effect of selenium was stronger with increasing quantile for total cholesterol and for triglycerides. In contrast, for LDL cholesterol the association was positive in the 10th and 50th percentiles, but (non-significant and) negative in the 90th percentile. These results show that while selenium may impact cardiovascular health via effects on lipid levels, the associations may not be linear. Copyright © 2015 Elsevier Inc. All rights reserved.
    Environmental Research 07/2015; 140. DOI:10.1016/j.envres.2015.03.020 · 3.95 Impact Factor
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    • "Similarly, Great Britain has undertaken efforts to develop soil amendment practices with inorganic-Se designed to increase dietary Se intake in the general population via the Se biofortification of food crops (reviewed by Rayman, 2012). For this purpose, the successful use of inorganic-Se fertilizers is, however, strongly dependent on physical soil conditions, low sulphate concentrations , and decreased organic matter, which all can negatively influence the overall uptake of inorganic-Se (Terry, Zayed, DeSouza, & Farun, 2000). "
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    ABSTRACT: Amending soils with Se-hyperaccumulator plant derived sources of selenium (Se) may be useful for increasing the Se content in food crops in Se-deficient regions of the world. In this study we evaluated total Se and the different chemical species of Se in broccoli and carrots grown in soils amended with ground shoots of the Se-hyperaccumulator Stanleyapinnata. With increasing application rates of S. pinnata, total plant Se concentrations increased to nutritionally ideal levels inside edible parts. Selenium compounds in aqueous extracts were analyzed by SAX-HPLC-ICPMS and identified as a variety of mainly organic-Se forms. Together with bulk Se K-edge X-ray absorption near-edge structure (XANES) analysis performed on broccoli florets, carrot roots and shoots, dried ground S. pinnata, and the amended soil at post-plant, we demonstrate that Se-enriched S. pinnata is valuable as a soil amendment for enriching broccoli and carrots with healthful forms of organic-Se.
    Food Chemistry 01/2015; 166(1):603-608. DOI:10.1016/j.foodchem.2014.06.071 · 3.26 Impact Factor
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    • "Selenium (Se) is a naturally occurring micronutrient with essential biological functions for all mammalian species. Interest in compounds containing selenium has increased in the past three decades, mainly due to their biological activities (Rayman, 2012). It is known to play an important role in both antioxidant defense (Ahmad et al., 2012) and immune function (Mehdi et al., 2013) and belongs to one of the most extensively studied chemopreventive and anticancer compounds (Ibáñez et al., 2011; Jayaprakash and Marshall, 2011; Moreno et al., 2012; Lamberto et al., 2013). "
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    ABSTRACT: Mycorrhizal inoculation can enhance the nutritional value of lettuces. However, the role of arbuscular mycorrhizal fungi (AMF) in biofortification of selenium (Se) in lettuce is unknown. We tested the capacity of two cultivars of lettuces, inoculated or not with AMF, for accumulating Se in shoots after applying sodium selenite or new synthesized organic selenocompounds. Sodium selenite was the most effective for increasing Se in shoots, but it decreased levels of macronutrients, micronutrients and proteins in one cultivar. Mycorrhizal inoculation reduced the accumulation of Se in leaves, but inoculated plants had higher contents of minerals, proteins and/or sugars than the non-inoculated controls supplied with Se. Mycorrhizal inoculation may impair the biofortification of lettuces with Se, but could be adequate for cultivating lettuces on soils rich in Se. The organic imidoselenocarbamate improved the effectiveness of AMF for enhancing growth, and proteins and sugars in leaves of one greenhouse-grown cultivar of lettuce.
    Scientia Horticulturae 12/2014; 180:40–51. DOI:10.1016/j.scienta.2014.09.049 · 1.50 Impact Factor
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