Food-chain selenium and human health: spotlight on speciation

• Published in: British journal of nutrition 2008-08, Vol.100 (2), p.238-253
• Main Authors: Rayman, Margaret P., Infante, Heidi Goenaga, Sargent, Mike
• Format: Article
• Language: English
• Subjects: analytical methods; animal-based foods; Animals; Bioavailability; biochemical pathways; Biological and medical sciences; Cancer; Diet; dietary mineral supplements; dietary minerals; Dietary supplements; Dietary Supplements - analysis; Feeding. Feeding behavior; Food; Food Analysis; Food Chain; Food chains; foods; Fundamental and applied biological sciences. Psychology; Human health; human nutrition; Humans; literature reviews; mass spectrometry; Metabolism; Metabolites; mineral content; mineral metabolism; molecular weight; nutrient uptake; Nutritive Value; plant-based foods; Plants, Edible - metabolism; Selenium; Selenium - analysis; Selenium - chemistry; Selenium - metabolism; Selenium in foods; selenium speciation; Speciation; Transfer RNA; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114508922522

There is a growing appreciation that it is not just the total intake of dietary Se that is important to health but that the species of Se ingested may also be important. The present review attempts to catalogue what is known about Se species in foods and supplements and the health effects in which they are implicated. The biosynthetic pathways involved in Se assimilation by plants and the way in which Se species are metabolised in animals are presented in order to give an insight into the species likely to be present in plant and animal foods. Known data on the species of Se in the food chain and in food supplements are tabulated along with their concentrations and the analytical methodology used. The latter is important, since identification that is only based on retention-time matching with authentic standards must be considered as tentative: for evidence of structural confirmation, fragmentation of the molecular ion in addition to MS data is required. Bioavailability, as normally defined, is higher for organic Se species. Health effects, both beneficial and toxic, thought to be associated with specific Se species are described. Potent anti-tumour effects have been attributed to the low-molecular-weight species, Se-methyl-selenocysteine and its γ-glutamyl-derivative, found in a number of edible plants of the Allium and Brassica families. There remain considerable gaps in our knowledge of the forms of Se that naturally occur in foods. Without adequate knowledge of Se speciation, false conclusions may be drawn when assessing Se requirements for optimal health.