EFFECT OF ZINC SUPPLEMENTATION ON THE MORBIDITY, IMMUNE FUNCTION, ANDGROWTH OF LOW-BIRTH-WEIGHT, FULL-TERM INFANTS IN NORTHEAST BRAZIL

In Brazil, the highest incidence of low birth weight (LBW) occurs in t he northeast, and diarrhea and respiratory infections are the main cau ses of infant mortality and morbidity. We hypothesized that LBW infant s may be zinc deficient, and that this might be adversely affecting th eir immune function, morbidity, and postnatal growth. We therefore exa mined the effect of zinc supplementation on these outcomes during the first 6 mo of life. LBW full-term infants (mean birth weight 2337 g) w ere given daily for 8 wk either 5 mg Zn (n = 71), I mg Zn (n = 68), or a placebo (n = 66). Morbidity was determined prospectively through da ily home visits (except on Sunday) during weeks 0-8, then twice weekly in weeks 9-26. Anthropometric measurements were made at 0, 4, 8, 17, and 26 wk. Immune function was assessed at 8 wk by the phytohemaggluti nin skin test. Supplementation (5 mg Zn) was associated with a 28% red uction in diarrhea prevalence over the 6-mo period [after adjustment f or confounders (P = 0.043)], and a 33% reduction in the prevalence of cough (NS, adjusted prevalence P = 0.073). All infants had a positive immune response at 8 wk. Although supplementation had no significant e ffect on weight and length gains from 0 to 26 wk, infants given 5 mg Z n gained more weight than infants given placebo during weeks 17-26 (P = 0.024, analysis of variance). There was no effect on any outcome wit h 1 mg Zn. We conclude that 5 mg Zn/d is of benefit to LBW, full-term Infants who only have a modest weight deficit.