Blood selenium levels and factors influencing concentration values

Recent values for blood selenium concentrations in healthy persons in Belgium, Europe and worldwide are reviewed. Various factors, which probably influence the blood selenium concentration level of people residing in a given geographical area, are discussed. The literature is screened for the effects of age, gender, smoking and drinking habits, race, state of lactation, environmental exposure and medical treatment on concentration levels. The differences are mostly found to be small on the absolute scale, with only nutrition seeming to be a major factor. Selenium values in pathological conditions are not intensively discussed because it is not always well understood. Moreover, enhanced or decreased levels may be the cause or the consequence of the disease and hence do not give an indication of the etiology and physiopathological consequences of changes. The interested reader is only referred to some interesting and recent papers. Quite new in the interpretation of observed levels is gene polymorphism. This can be situated either in genes coding for selenium-dependent enzymes or other proteins. The first publications on selenium and the related field of nutrigenomics are included.