Lack of association between copper, zinc, selenium and blood pressure among healthy children.

Contradictory results have been published about the relation between copper, zinc and selenium and blood pressure (BP). To evaluate the role of these trace elements in BP regulation, we analysed the correlations between BP and copper, zinc and selenium, measured from serum, diet and hair among 3596 healthy children in a 6-year follow up. Fasting blood samples were used in serum copper, zinc and selenium analyses. The dietary intake of trace elements and energy were determined by the 48-h recall method. The hair copper and zinc analyses were performed from the naturally coloured hair samples. Correlation analysis was used to show the relation between BP and copper, zinc or selenium in each study year and during a 3- or 6-year follow-up period. The zinc-to-copper ratio in serum, diet and hair was calculated. In the correlation analyses the data was adjusted for weight and the daily intake of energy. Neither serum and diet copper or zinc, nor the zinc-to-copper ratio correlated uniformly with BP measured in the same year (correlation coefficients varying from -0.12 to 0.18) or in the subsequent years. Hair copper and zinc correlated weakly negatively with BP (correlation coefficients varying from -0.17 to -0.01). Serum selenium correlated weakly positively with systolic and diastolic BP measured in the same year (correlation coefficients varying from 0.03 to 0.14), but not with subsequent BP measured in the second or third survey. Dietary selenium had an inconsistent effect on BP (correlation coefficients varying from -0.14 to 0.26). In conclusion, copper, zinc, their ratio or selenium did not associate with BP, nor did they have any effect on subsequent BP.