Metabolism of selenate and selenomethionine by a selenium-deficient population of men in China

Abstract

Twenty young Chinese men (ages 18–40 with a mean age of 29 years) living in a selenium deficient area of China (Dechang county. Sichuan province) were selected, divided into two groups, and provided with 200 μg selenium daily for 1 year as either selenate or selenomethionine (Semet). Blood and 24-hour urine samples were collected initially, after 1 month of supplementation and subsequently at bimonthly intervals. Selenium increased in both plasma and erythrocytes at a significantly faster rate in deficient men taking Semet than in those taking selenate. Glutathione peroxidase (GSH-Px) activity increased in both plasma and erythrocytes up to 4 months where a plateau was reached, but there were no differences in this activity between these two supplemental groups. The percentage of selenium associated with GSH-Px was significantly lower in plasma and erythrocytes in men taking. Semet than in those taking selenate. Gel filtration chromatography revealed two selenium-containing peaks in plasma of men taking Semet but mostly one in plasma from men taking selenate. Urinary excretion of selenium gradually increased throughout this study, but there were no differences in the excretion of total selenium or trimethylselenium (TMSe) between the two treatment groups. The TMSe content ranged between 1%–2.5% of total selenium in both groups.