After a 5-week period of low selenium intake, twenty-four Dutch men received 55, 135 or 215 μg Se/d as Se-rich meat or bread for a 9-week period. Four unsupplemented subjects served as controls. Plasma Se increased more rapidly than erythrocyte Se levels; the increases were significantly dependent (P < 0.001) on Se intake level. Glutathione peroxidase (EC1.11.1.9; GSH-Px) activity in platelets increased rapidly after supplementation and plateaued after 4–9 weeks. At 10 weeks after supplementation ended, plasma Se levels and platelet GSH-Px were still higher than the baseline values whereas erythrocyte Se levels continued to increase. Except for the higher erythrocyte Se levels after supplementation with high-Se meat, there were no differences in bioavailability of Se between meat and wheat products. Daily urinary and faecal Se excretions as well as Se retention increased with an increased Se intake irrespective of the form of the supplement. Regression of Se excretion ν. intake indicated that 33 μg Se/d is necessary to compensate for urinary and faecal losses
