Supplementation with wheat selenium induces a dose-dependent response in serum and urine of a Se-replete population

In spite of a rather modest dietary intake of selenium (80 micrograms/10 MJ), Norwegian serum Se levels are among the highest in Europe. As part of an ongoing study of Se bioavailability, effects of different doses of wheat Se were investigated in eighteen healthy, Norwegian women. The participants were given Se-rich bread providing 100, 200 and 300 micrograms Se daily for 6 weeks. About 50% of the Se intake was excreted in the urine by week 6, compared with 67% before the intervention started. Serum Se increased by 20, 37 and 53 micrograms/l respectively, in the three group (P less than 0.001). The blood response and renal clearance results compare well with data obtained from less Se-replete populations, and support the hypothesis that selenomethionine from the diet is incorporated into a non-specific amino acid pool. Our study indicates that the intake of wheat Se is the main determinant of blood Se levels in Norway.