This looks like an interesting article on selenium and looks at supplementation for cancer prevention.
RB
http://www.jacn.org/cgi/content/full/20/1/1
Commentary
Nutritional Selenium Supplements: Product Types, Quality, and Safety
Gerhard N. Schrauzer, PhD, CNS, FACN
Department of Chemistry and Biochemistry, University of California San Diego, and, Biological Trace Element Research Institute, San Diego, California
Address reprint requests to: Gerhard N. Schrauzer, PhD, CNS, FACN, Biological Trace Element Research Institute, 11526 Sorrento Valley Rd., Ste. A., San Diego, CA 92121.
ABSTRACT
Selenium supplements contain selenium in different chemical forms. In the majority of supplements, the selenium is present as selenomethionine. However, in multivitamin preparations, infant formulas, protein mixes, weight-loss products and animal feed, sodium selenite and sodium selenate are predominantly used. In some products, selenium is present in protein- or amino acid chelated forms; in still others, the form of selenium is not disclosed. Current evidence favors selenomethionine over the other forms of selenium. Extradietary supplementation of selenium at the dosage of 200 micrograms per day is generally considered safe and adequate for an adult of average weight subsisting on the typical American diet.
Key words: selenium, selenomethionine, selenium yeast, sodium selenite, sodium selenate, dietary supplements
The typical American diet provides the average adult with about 80 to 150 micrograms of selenium per day, which is more than the newly revised RDA for selenium of 55 ยต [1], but less than one half of the amount considered optimal for utilization of the protective potential of selenium, especially for cancer prevention [2,3]. Accordingly, extradietary selenium supplementation is increasingly recommended by health professionals. Pending the outcome of ongoing human cancer prevention trials, selenium supplementation is likely to be officially recognized as a means of lowering cancer risk. These developments raise the question as to which form of selenium is the most desirable for supplementation. In addition, the quality and safety of the selenium supplements become matters of concern.