Zinc and copper status of Polynesian residents in the Tokelau Islands

Abstract

Analyses for zinc and copper were performed in samples of serum, hair, toenails, and a 24-hr urine from Polynesian men and women resident in the Tokelau Islands. Selection of subjects was according to rank of systolic blood pressure obtained in a previous survey. The only difference in zinc and copper values between the men and the women was a higher hair zinc concentration observed for the men. Rank of blood pressure had no influence on the measurements for zinc or copper, although within blood pressure ranks the men again had a higher hair zinc concentration than the women. Analysis of Tokelauan foods showed that most contained very low concentrations of zinc and also low concentrations of copper. Octopus was one of the few rich sources of zinc and copper. Estimated daily dietary intakes (excluding water) were 4.5 mg Zn and 1.5 mg Cu. The reliability of measurements in serum, urine, hair, and toenails for assessing zinc and copper status is questioned.