ZINC STATUS OF A GROUP OF PREGNANT ADOLESCENTS AT 36 WEEKS GESTATION LIVING IN SOUTHERN ONTARIO

Objective: Pregnant adolescents have very high zinc (Zn) requirements to support the developing fetus and to maintain skeletal maturation af ter menarche. Methods: Sixty-six adolescents aged 17.1 +/- 0.15 years (mean +/- SEM; range 14.5-19.0 years) were recruited from three region s of Southern Ontario at 35.9 +/- 0.15 weeks gestation. Data on sociod emographic status, health, infant birth weight and birth length, smoki ng, alcohol consumption, and prenatal supplement use were collected. F asting venipuncture blood was analyzed for Zn (via AAS) and alkaline p hosphatase in plasma; scalp hair was analyzed for Zn by instrumental n eutron activation. Results: Mean (95% CI) values were: plasma Zn 10.7 (10.0-11.5) mumol/L; plasma alkaline phosphatase 46.6 (43.7-49.5) U/L; hair Zn 2.64 (2.52-2.77) mumol/g. None of the plasma and hair Zn valu es were indicative of suboptimal Zn status. Mean plasma Zn concentrati ons of subjects (n = 19) consuming a supplement with Zn sulfate were h igher than those of subjects consuming a supplement with Zn oxide (n = 18) (12.2 vs 9.7 mumol/L; p < 0.02) and unsupplemented subjects (n = 11) (9.4 mumol/L). Plasma Zn concentrations correlated negatively with reported birth lengths (mean +/- SEM = 51.6 +/- 0.31 cm) while accoun ting for chronological age (r = 0.42; p < 0.01), but not with reported birth weights (mean +/- SEM = 3.439 +/- 0.107 kg). Conclusions: Resul ts emphasize that the form of Zn must be taken into account when consi dering the impact of prenatal supplements containing Zn on plasma Zn c oncentrations, Suboptimal Zn status was not prevalent in these pregnan t adolescents.