Zinc supplementation increases the level of serum insulin-like growth factor-I but does not promote growth in infants with nonorganic failure to thrive

We investigated in a randomized double-blind placebo-controlled study the e ffects of zinc supplementation (2 mg/kg/day) for 12 weeks on growth, serum insulin-like growth factor-I (IGF-I) and insulin-like factor binding protei n-3 (IGFBP-3) on 3- to 9-month-old infants with nonorganic failure to thriv e (NOFTT). 25 infants completed the study, 14 received zinc supplementation (group A), and 11 received placebo (group B). The control group for baseli ne measurements was composed of 10 age-matched normal growing infants. Ther e were no significant changes in weight for age, length for age, or weight for length during the entire study period in either group A or B. Serum IGF -I levels at baseline were similar in all the groups. After 12 weeks of the rapy, serum IFG-I levels increased significantly only in the zinc-supplemen ted group, from 40.3 +/- 7 ng/ml at baseline to 65 +/- 8 ng/ml (p < 0.05). There was a marked difference in serum IGF-I levels between the zinc-supple mented group and the placebo group after 12 weeks: 65 +/- 8 vs. 49.4 +/- 5 ng/ml (p = 0.058, 95% CI of difference 9.88-21.31). No change was demonstra ted in serum IGFBP-3 levels in either study group. We conclude that althoug h zinc supplementation increased serum IGF-I levels, it did not improve the growth parameters of infants with NOFTT. Copyright (C) 2000 S. Karger AG. Basel.