Pure and Applied Chemistry

Abstract: Selenium yeast, produced by growing select strains of Saccharomyces cerevisiae in Se-rich media, is a recognized source of organic food-form Se, but the determination of its exact composition with respect to the Se species present produced conflicting results. Improved methods of analysis have since revealed it to contain 90+ % of its Se in the form of selenomethionine, the principal organic nutritional form of Se for higher animals and humans. The safety record of Se yeast is excellent: During the three decades of its world-wide use as a source of supplemental Se, no cases of Se poisoning have occurred due to dosage or formulation errors.