Plasma extracellular superoxide dismutase activity in healthy pregnant women is not influenced by zinc supplementation

We hypothesized that plasma extracellular superoxide dismutase (EC-SOD) act ivity reflects the zinc nutriture of healthy pregnant women. Sixty-three wo men were selected from 580 African-American women who participated in a cli nical trial to evaluate the effect of prenatal zinc supplementation on preg nancy outcome. Half of the women received zinc (25 mg/d) and the other half was given a placebo from about 19 wk gestation to delivery. In the trial, a positive effect of zinc supplementation on birthweight was observed, indi cating that the population as a whole had suboptimal zinc nutriture. Using plasma samples obtained during the trial, EC-SOD activities were measured a nd the values were compared with plasma zinc concentrations and plasma alka line phosphatase activities. Plasma EC-SOD activities in our subjects were Lower than previously published values for healthy adults in Korea. Althoug h plasma EC-SOD activity may reflect severe zinc deficiency, it is not a se nsitive marker for marginal deficiency status. Plasma EC-SOD activities did not prove to be a better indicator of zinc nutriture of pregnant women tha n either plasma zinc or plasma alkaline phosphatase activities.