Selenium‐iron interaction in young women with low selenium status

Abstract

The effect of inorganic selenium (Se) supplementation on iron status and iron supplementation on selenium status was investigated in Finnish female students (=33). The students were divided into three groups and supplemented daily for four weeks either with 150 μg Se as sodium selenate, or 120 mg Fe as ferrous sulfate, or 120 mg Fe as ferrous sulfate and 150 μg Se as sodium selenate. Plasma selenium level was used as an indicator of body selenium status. Haematocrit and serum ferritin concentrations were measured to determine the changes in body iron status. The initial plasma selenium level of all subjects was 74.7 ± 2.9 ng/ml (mean ± SEM). The increase in the plasma Se level in the group receiving sodium selenate was significantly higher (P<0.05) than in the group having both sodium selenate and ferrous sulphate. The plasma selenium level in the group receiving ferrous sulphate decreased from 76.0 ± 2.8 ng/ml to 67.8 ± 2.3 (P<0.05) during the supplementation period, but returned to the initial level four weeks after the end of iron supplementation. The data indicate that the supplementary iron affected adversely the body selenium status of these subjects. On the other hand, Se supplementation had no effect on body iron status as indicated by the serum ferritin and haematocrit levels. It was also shown that there was no obvious interaction between the normal levels of selenium and iron in the body, since no correlations were found between plasma selenium and serum ferritin (r = 0.30, P>0.05) in the beginning of the study.