Zinc and copper status of adolescent females

Abstract

Dietary, plasma and erythrocyte zinc and copper status of 92 adolescent females 14–16 years of age (38% were black) were evaluated. Two 24-hour dietary recalls were used to assess dietary intakes. Plasma and RBC concentrations were analyzed by atomic absorption spectroscopy. Mean dietary zinc intake was 81% of the RDA for this population. Ten percent of the adolescent females were marginally deficient in zinc on the basis of plasma levels (<70 ug/100 ml) and 22% were marginally deficient on the basis of RBC zinc (<8.0 ug/gm of RBC). Dietary copper intake (X=1.4±0.7mg/day) was less than the suggested intake, however, all measures of plasma and RBC copper were within the normal range. RBC copper (X=125±16.2 ug/100 ml RBC) was inversely correlated with plasma zinc (r=−0.32; p=0.002) and the ratio of zinc to copper in plasma (r=−0.30; p=0.005). RBC copper was inversely correlated with the dietary Zn/Cu ratio (r=−0.21; p=0.04). About one-third of the adolescent females females consumed less than 2/3 of the RDA for zinc which was consistent with marginal zinc blood levels. RBC copper was inversely correlated with zinc status. Normal plasma and RBC copper levels were observed despite the fact that dietary copper intake was less than 2/3 the suggested level among 70% of this population. Thus the dietary copper needed for normal blood copper levels may be lower than the suggested intake cited in the RDA (1980).