The effects of zinc supplementation on clinical response and metabolic profiles in pregnant women at risk for intrauterine growth restriction: a randomized, double-blind, placebo-controlled trial

Abstract

Objective This investigation was conducted to assess the effects of zinc supplementation on clinical response and metabolic status among pregnant women at risk for intrauterine growth restriction (IUGR). Methods This randomized, double-blind, placebo-controlled, clinical trial was conducted among 52 women at risk for IUGR according to abnormal uterine artery Doppler waveform. Participants were randomly assigned to take either 233 mg zinc gluconate (containing 30 mg zinc) supplements (n = 26) or placebo (n = 26) for 10 weeks from 17 to 27 weeks of gestation. Fasting blood samples were taken at baseline and after the 10-week treatment to quantify related variables. Results After the 10-week intervention, taking zinc led to a significant reduction in serum high-sensitivity C-reactive protein (hs-CRP) (β ‒1.17 mg/L; 95% CI, −1.77, −0.57; p < .001) and plasma malondialdehyde (MDA) levels (β −0.23 µmol/L; 95% CI, −0.45, −0.02; p = .03); also a significant rise in total antioxidant capacity (TAC) (β 59.22 mmol/L; 95% CI, 25.07, 93.36; p = .001) was observed in comparison to placebo. In addition, zinc supplementation significantly reduced serum insulin (β –1.33 µIU/mL; 95% CI, −2.00, −0.67; p < .001) and insulin resistance (β –0.30; 95% CI, −0.44, −0.15; p < .001), and significantly increased insulin sensitivity (β 0.008; 95% CI, 0.003, 0.01; p < .001) compared with the placebo. Zinc supplementation did not influence pulsatility index (PI) and other metabolic parameters. Conclusions Overall, zinc supplementation in pregnant women at risk for IUGR had beneficial effects on TAC, MDA, hs-CRP, and insulin metabolism, but did not affect PI and other metabolic profiles.