Trace element status (Se, Cu, Zn) in healthy Portuguese subjects of Lisbon population: a reference study

Serum levels of selenium, copper, and zinc were systematically determined in healthy subjects of the Lisbon population. The sample consisted of 183 blood donors of both genders who were divided into two age groups: 20-44 and 45-70 yr of age; relationships with gender, age, the lipid profile, and tobacco consumption were investigated. In the female group, the intake of oral contraceptives and pregnancy were considered for the youngest women, and hormonal replacement therapy (HRT) was taken into account for the oldest ones. Serum concentrations of these elements were in the same range as those found for populations of other European countries. Differences between genders were observed for the three elements studied, with serum selenium and zinc concentrations higher in men and copper levels higher in women. Age-dependent differences were found for selenium: The oldest subjects (regardless gender) presented the highest concentrations of selenium in serum as further demonstrated by the positive correlation with age. In both pregnant and contraceptive-using women, copper was greatly increased, confirming the influence of estrogen status and/or oral contraceptive intake on increased serum copper levels. However, in postmenopausal women, HRT did not significantly affect serum copper levels. Selenium, copper, and zinc status were not different between normolipidemic and hyperlipidemic subjects for the same gender and age range, but selenium levels tended to increase with hyperlipidemia when considering the whole group of subjects. With respect to the lifestyle, higher serum zinc levels were found in tobacco-consuming men. Albumin serum levels were similar for all considered subgroups, except for the pregnant women, for whom a decrease in this parameter was observed. The present study allowed one to obtain reference values for this healthy group of population, which will serve for a comparative study with groups having pathological conditions, such as cardiovascular disease.