Update of human dietary standards for selenium

Abstract

An update of the human dietary standards for selenium is presented, including the year 2000 Dietary Reference Intakes (U.S.A.), the 1996 standards of the World Health Organization (WHO), and a recent relevant intervention trial carried out in China. Two criteria have been used by official bodies to set recommendations. One is the prevention of Keshan disease, the only proven selenium-responsive disease. The other is full expression of all selenoproteins as indicated by optimization of a plasma biomarker, either glutathione peroxidase activity or selenoprotein P concentration. An average per capita intake of 20 μg selenium/day will prevent Keshan disease in a population but will not allow optimization (full expression) of selenoproteins. Using plasma glutathione peroxidase activity as the selenium biomarker to be optimized, the RDA for adults in the U.S.A. was set at 55 μtg in 2000. The recent trial in China utilized selenoprotein P as a biomarker and its results suggest that an upward revision of the current RDA will be needed. Even higher intakes of selenium have been postulated to prevent cancer. Intervention trials now underway in the U.S.A. are evaluating that possibility and the safety of large selenium supplements.