Zinc supplementation during pregnancy: zinc concentration of serum and hair from low-income women of Mexican descent

Abstract

The effect of zinc supplementation on concentrations of zinc in hair and serum of 213 pregnant Hispanic women attending a clinic in Los Angeles was assessed using a random, double-blind experiment. Both the treatment (T) and control (C) groups received similar vitamin and mineral supplements except that 20 mg zinc was added to the supplements for the treatment group. Nutrient intakes were calculated from 24-h recalls. The initial mean dietary zinc intake of both groups was about 50% of the Recommended Dietary Allowance (9 ± 5 mg). Initially there were no significant differences between the two groups in mean zinc levels in serum (66 ± 11 µg/ dl, C, and 65 ± 12 µg/dl, T) or in hair (184 ± 41 µg/g, C, and 175 ± 38 µg/g, T). Zinc supplementation did not alter mean zinc levels in serum or hair but significantly (p < 0.05) reduced the number of low serum zinc values (≤53.3 µg/dl) toward the end of pregnancy. Although serum zinc levels do decline in pregnancy, our results suggest that severely depressed levels (≤50 to 55 µg/dl) indicate inadequate zinc status.