Metabolism of Subtoxic Levels of Selenium in Animals and Humans

The study explored the metabolism of subtoxic levels of selenium in animals and humans, focusing on absorption patterns and potential toxicity. It was found that the intestinal tract had a high tolerance to selenium, with selenomethionine (SeMet) being absorbed most efficiently in vivo, while selenite was absorbed most rapidly by brush border membrane vesicles. Selenodiglutathione and selenodicysteine were absorbed faster than selenite. In a high selenium area in China, selenium was primarily associated with albumin in plasma, likely due to high dietary SeMet intake, with symptoms of toxicity including cracked fingernails and hair loss. The study calculated the low adverse effect level (LOAEL) of dietary selenium to be approximately 1540 micrograms per day, and the maximum safe dietary level (NOAEL) to be 819 micrograms per day.