Selenium speciation from food source to metabolites: a critical review

Abstract

Especially in the last decade, a vast number of papers on Se and its role in health issues have been published. This review gives a brief, critical overview of the main analytical findings reported in these papers. Of particular interest is the Se content in different food sources worldwide and the extent to which their consumption is reflected in the Se content of human tissues and body fluids. Several food sources, both natural (Brazil nuts, garlic, Brassica juncea) and Se-enriched (yeast-based supplements), are discussed as to origin, characteristics, Se metabolism and impact of their consumption on the human body. The continuous development of new and improvement of existing analytical techniques has provided different powerful tools to unravel the Se species and their function. An up-to-date literature study on Se speciation analysis is given, illustrating how analytical chemistry in its different facets aids in the identification of Se compounds and provides insight into the complete metabolic pathway of Se throughout the human body. This review includes a detailed image of the current state-of-the-art of Se speciation analysis in these food sources and in human tissues and body fluids.

Blood dynamics of mercury and selenium in northern elephant seals during the lactation period

“…The mammary-gland regulating mechanism controls the synthesis and secretion of Se compounds throughout lactation, with the highest amount of Se excreted in the beginning of lactation (Dumont et al, 2006). In human milk, worldwide Se values range between 13 and 33 mg/l and variations in levels are mainly due to fluctuations in the Se intake via food (Dumont et al, 2006).…”

“…This (HgSe)eSel P is thought to also be a precursor of the crystalline HgSe (Ikemoto et al, 2004). Selenium is beneficial at lower concentrations, but it becomes toxic at higher concentrations (Dumont et al, 2006;Janz et al, 2010;Kim and Mahan, 2001), and the range between deficiency, essentiality, and toxicity is very narrow. Marine mammals do not appear to be as sensitive to dietary organic Se exposure as fish or birds, but no data concerning the ratio between essentiality and toxicity exist for wild aquatic mammalian species (Janz et al, 2010).…”

Selenium biochemistry and its role for human health

“…Nevertheless, Se in crops is generally of low abundance because such plants do not require Se for growth, and hence do not accumulate it under normal physiological conditions. A level ranging between 10-550 mg kg À1 of Se (fresh wt) was reported in cereals, 10 whereas Se in bread is generally found at a level of B60-160 mg kg À1 . 9 Other vegetables such as those of the Allium family, including garlic and onion, can accumulate significant amounts of Se, reaching concentrations of Se up to 68 and 96 mg g À1 , respectively.…”

Cu, Fe, Mn and Zn distribution in protein fractions of Brazil-nut, cupuassu seed and coconut pulp by solid-liquid extraction and electrothermal atomic absorption spectrometry

“…[5][6][7][8] In the latest years, fruits and nuts from Amazon region have arisen interest among the scientific community due to the high concentrations of some essential elements in their compositions. [9][10][11][12][13][14][15][16][17] Special attention are devoted to Brazil-nut (Bertholletia excelsa), known as "castanha-doPará". This nut is a rich source of nutrients, such as proteins (10-20%, m/m), fat (50-70%, m/m), carbohydrates (10-20%, m/m), vitamins, minerals and dietary fiber.…”

“…The protein standard was prepared dissolving 4.0 mg of ovoalbumin in 2.0 mL of deionized water, submitted to Vortex stirring for 2 min and diluted 10 times with deionized water. The spectrophotometer calibration was performed using analytical reference solutions of 4,6,8,10,12,16 and 20 μg of ovoalbumin in 1.0 mL of Bradford reagent.Water, NaCl, and NaOH extracts of the Brazil-nut samples were diluted 100 times and ethanol extract was diluted 10 times. A volume of 50 μL of these solutions was used for protein determination.…”