Selenium levels and glutathione peroxidase activities in blood in an Andean high-altitude population

Selenium (Se) levels in blood (whole blood, erythrocytes and serum) and blood glutathione peroxidase (GSH-Px) activity were investigated in people living at high altitude in Bolivia (4, 000m above sea level). These parameters were compared to those of people living at low altitude (300m above sea level). The Se levels in whole blood of the high-altitude subjects did not differ significantly from those of the low-altitude subjects. However, the Se levels in erythrocytes were significantly lower in the high-altitude subjects than in the low-altitude subjects, whereas serum Se levels were higher in the high-altitude subjects than in the low-altitude subjects. GSH-Px activity (Unit/g Hb) was significantly lower in the high-altitude subjects than in the low-altitude subjects. The mean corpuscular Hb concentration (MCHC), an indicator of the age of erythrocytes, in the high-altitude subjects was significantly higher than in the low-altitude subjects. These results show that the GSH-Px activity in the blood of the high-altitude subjects is relatively low. This may be due to their aged erythrocytes and/or to relatively low Se intake in the high-altitude population compared with low-altitude population.