Selenium bioavailability

Two types of epidemiological relationships have been found in two different populations. Both relationships were inverse to selenium bioavailability and paralleled the results from animal studies. In one type of study, selenium bioavailability has been inversely related to human cancer mortality in American cities and states (14-15). Schrauzer et.al. correlated the age-adjusted mortality from cancer at 17 major body sites with the apparent dietary selenium intakes estimated from food consumption data in 27 countries (16). Significant inverse correlations were observed for cancers of the large intestine, rectum, prostate, breast, ovary, lung, and leukemia. In addition, weaker inverse associations were found for cancers of the pancreas, skin, and bladder. 

Luoma, S.N., Johns, C., Fisher, N.S., Steinberg, N.S., Oremland, R.S., and Reinfelder, J.R. (1992) Determination of selenium bioavailability to a benthic bivalve from particulate and solute pathways. Environ. Sci. Technol. 26, 485 192. 

Yin, S., Jin, Y., and Kenji, Y. 1996. Effect of dietary vitamin B6 on selenium bioavailability. IV. Effect of dietary vitamin B6 on selenium bioavailability from different chemical forms and lipid peroxidation in rats. Weishung Yanjiu 25(5), 296-300. 

J. Cases, I. A. Wysocka, B. Caporiccio, N. Jouy, P. Besangon, J. Szpunar, J. Rouanet, Assessment of selenium bioavailability from high-selenium spirulina subfractions in selenium-deficient rats, J. Agric. Food Chem., 50 (2002), 3867-3873. 

Several techniques are available to assess selenium bioavailability in soils. The most widely used is the water-soluble concentration (Fordyce et al., 2000b Jacobs, 1989 Tan, 1989). In most soils, only a small proportion of the total selenium is in dissolved form (0.3-7%), and water-soluble selenium contents are generally <0.1mgkg (Table 8). 

Young VR, Nahapetian A, Janghorbani M. 1982. Selenium bioavailability with reference to human nutrition. Am J Clin Nutr 35 1076-1088. 

Fairweather-Tait, S., Collings, R., and Hurst, R. (2010) Selenium bioavailability current knowledge and future research requirements. Am. 

Another contaminant of concern for the Delta is Se. Selenium occurs in high concentrations in the soils of the western San Joaquin Valley associated with salts that have accumulated in this region [10]. Selenium is recycled through agricultural retom flows to the river and transported to the Delta and San Francisco Bay. The Se is transformed into a more bioavailable form by microbial communities and aquatic plants. The Se is passed through the foodweb with particular concern for bottomfeeding migratory waterfowl and predatory fishes. The hydrodynamics of water from the San Joaquin River is an important consideration in the intensity and distribution of Se contamination within the Delta. 

Whanger PD, Ip C, Polan CE, Uden PC and Welbaum G. 2000. Tumorigenesis, metabolism, speciation, bioavailability, and tissue deposition of selenium in selenium-enriched ramps (Allium tricoccum). J Agric Food Chem 48(11) 5723-5730. 

The bioavailability of selenium to a benthic deposit-feeding bivalve, Macoma balthica from particulate and dissolved phases was determined from AE data. The selenium concentration in the animals collected from San Francisco Bay was very close to that predicted by a model based on the laboratory AE studies of radiolabelled selenium from both particulate and solute sources. Uptake was found to be largely derived from particulate material [93]. The selenium occurs as selenite in the dissolved phase, and is taken up linearly with concentration. However, the particle-associated selenium as organoselenium and even elemental selenium is accumulated at much higher levels. The efficiency of uptake from the sediment of particulate radiolabelled selenium was 22%. This contrasts with an absorption efficiency of ca. 86% of organoselenium when this was fed as diatoms - the major food source of the clam. The experiments demonstrated the importance of particles in the uptake of pollutants and their transfer through the food web to molluscs, but the mode of assimilation was not discussed. 

Cases, J., Vacchina, V., Napolitano, A., Caporiccio, B., Besancon, P., Lobinski, R., and Rouanet, J.-M. 2001. Selenium from selenium-rich spirulina is less bioavailable than from sodium selenite and selenomethionine in selenium-deficient rats. J. Nutr. 131(9), 2343-2350. 

Daniels, L.A. 1996. Selenium metabolism and bioavailability. Biol. Trace Elem. Res. 54, 185—199. 

Hemken, R.W. and Jacques, K.A. 1998. Bioavailability of selenium yeast (Sel-Plex) vs sodium selenite for dairy cattle. Proceedings of the 6th International Symposium on the Uses of Selenium and Tellurium, Selenium-Tellurium Development Association, May 10-12, 1998, Scottsdale, AZ, USA. pp 161-162. 

Levander, O.A., Alfthan, G., Arvilommi, H., Gref, C.G., Huttunen, J.K., Kataja, M., Koivistoinen, P., and Pikkarainen, J. 1983. Bioavailability of selenium in Finnish men as assessed by glutathione peroxidase activity and other blood parameters. Am. J. Clin. Nutr. 37, 887-897. 

E. H. Larsen, M. Hansen, H. Paulin, S. Moesgaard, M. Reid, M. Rayman, Speciation and bioavailability of selenium in yeast-based intervention agents used in cancer chemoprevention studies, J. AO AC lnt., 87 (2004), 225 D 232. 

C. Thomas, I. Buth, H. Waldner, Bioavailability investigations of selenium from foods and supplements after enzymatic digestion using HPLC-ICP-MS with hexapole collision cell. Poster presentation at the II. International Conference on Trace... 

The bioavailability and toxicity of copper, selenium, and arsenic for some aquatic organisms is higher in their inorganic form, but not in the presence of certain chelating ligands or metal-organic complexes. 

Although geology is the primary control on the selenium concentration of sod, the bioavailability of selenium to plants and animals is determined by other factors including pH and redox conditions, speciation, soil texture and mineralogy, organic matter content, and the... 

In general, selenate is more available and more mobile than selenite in the environment, so that selenium is much more bioavailable under oxidizing alkaline conditions. 

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