Background

Evidence for an effect of zinc supplementation on growth and morbidity in very young infants in developing countries is scarce and inconsistent.

Objective

We assessed the effect of zinc supplementation on growth and morbidity in poor Bangladeshi infants aged 4-24 wk.

Design

Infants from Dhaka slums were enrolled at 4 wk of age and randomly assigned to receive 5 mg elemental Zn/d (n = 152) or placebo (n = 149) until 24 wk of age. They were followed weekly for information on compliance and morbidity; anthropometric measurements were performed monthly. Serum zinc was assessed at baseline and at 24 wk of age.

Results

At 24 wk of age, serum zinc concentrations were higher in the zinc than in the placebo group (13.3 +/- 3.8 and 10.7 +/- 2.9 micro mol/L, respectively; P < 0.001). Significantly greater weight gains were observed in the zinc than in the placebo group for 43 infants who were zinc deficient (< 9.18 micro mol/L) at baseline (3.15 +/- 0.77 and 2.66 +/- 0.80 kg, respectively; P < 0.04). In the other infants, no significant differences were observed in mean weight and length gains during the study period. Zinc-deficient infants showed a reduced risk of incidence of acute lower respiratory infection after zinc supplementation (relative risk: 0.30; 95% CI: 0.10, 0.92); among the non-zinc-deficient infants there were no significant differences between treatment groups.

Conclusions

Zinc-deficient Bangladeshi infants showed improvements in growth rate and a reduced incidence of acute lower respiratory infection after zinc supplementation. In infants with serum zinc concentrations > 9.18 micro mol/L, supplementation improved only biochemical zinc status.