ABSTRACT
The image of selenium has changed from that of a toxic and carcinogenic substance into that of an essential trace element with antioxidant properties (1). Ecological studies on the estimated selenium intake per capita, blood concentrations, and cancer mortality
(2,3) were substantiated by animal experiments showing reduced tumorigenesis in laboratory rodents at adequate to high selenium levels (reviewed by Milner) (4). Postulated mechanisms include altered metabolism of carcinogens, reduction of their mutagenicity, inhibition of cell proliferation, stimulation of the immune system, and protection against oxidative damage.
