ABSTRACT
This chapter describes the biochemistry and bioavailability of selenium in order to understand the relationship of selenium in foods to health and nutrition. The selenium content of certain plants is a better predictor of soil selenium levels than is that of other plants. When discussing the selenium content of foods, one must consider the geographic origin of the product. Selenium status in humans has been measured by balance studies, blood selenium levels, glutathione peroxidase activity in blood components and absorption and retention of stable isotopes. A separate study on pregnant women showed high levels of selenium absorption but lower glutathione peroxidase levels in plasma and higher levels in platelets. The selenium status of the individuals may contribute to the variability in absorption. Balance studies have also been used to measure selenium absorption and retention. The chapter concludes that tissue glutathione peroxidase activity could be used as an indicator of animal selenium status.
