Influence of dietary habits on serum selenium concentration.
BACKGROUND: A serum selenium concentration of 70 microg/l is considered to be sufficient for glutathione peroxidase (GSHPx) activity, a selenium-dependent enzyme reflecting the body selenium status. The purpose of the study was to assess which foods or food groups best affect serum selenium in subjects with selenium concentrations below or above 70 microg/l. METHODS: A food frequency questionnaire was employed to describe the dietary habits of 129 subjects. Serum selenium concentrations were determined using the electrothermal absorption spectrometry (ETAAS) technique following serum dilution. RESULTS: Multiple regression analysis revealed that consumption of ham, honey and tea was positively associated with the selenium concentration in the sera of selenium-inadequate subjects. In selenium-inadequate subjects, alcohol consumption may be responsible for selenium losses. Unlike the selenium-inadequate subjects, the selenium concentrations in the sera of the selenium-adequate subjects were positively correlated with the frequencies of wholegrain bread consumption and processed fruit consumption. In all the groups tested, the serum selenium concentration was not affected by cigarette smoking. CONCLUSIONS: The serum selenium concentration is influenced by dietary habits, but not by cigarette smoking. Frequent consumption of ham, tea and honey may be effective to improve the selenium concentration in the sera of selenium-inadequate subjects.