An analysis of cancer prevention by selenium.
The nutritional functions of selenium (Se) are recognized as being due to a number of Se-containing proteins. It is not clear, however, whether any of these function in the anti-tumorigenic effects of Se most of which have been demonstrated for Se exposures greater than those required for selenoprotein expression. Indeed, other anti-tumorigenic mechanisms have been demonstrated for certain Se-metabolites. The Nutritional Prevention of Cancer Trial found supplemental Se (200 microg/day, as Se-enriched yeast) to be associated with significant reductions in cancer risks in subjects with pre-treatment plasma Se concentrations below ca. 120 ng/ml (1.5 nmoles/ml), which level would appear to require food-Se intakes of ca. 1.5 microg/kg body weight/day. However, the putative anti-carcinogenic Se-metabolite(s) should be more relevant than total plasma Se as a supplementation target for cancer prevention. These may be components of the non-protein-bound fraction of Se in plasma, which constitutes 2-4% of total plasma Se.
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Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA. gfc2@cornell.edu
Clark
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Turnbull
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D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D006801:Humans; D009369:Neoplasms / Q000517:prevention & control*; D014176:Protein Biosynthesis; D011506:Proteins; D012643:Selenium / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*; D051140:Selenoproteins
D016588:Anticarcinogenic Agents; D011506:Proteins; D051140:Selenoproteins; D012643:Selenium