Effects of oral zinc supplementation on zinc status and catch-up growth during the first 2 years of life in children with non-organic failure to thrive born preterm and at term

Abstract

BackgroundWe aimed to analyze the effect of oral zinc supplementation on serum insulin-like growth factor-1 (IGF-1) levels and catch-up growth in infants with non-organic failure to thrive (NOFTT) who were born preterm as compared to those born at term. MethodsTotally, 105 NOFTT infants aged 2 years or less were enrolled and divided into two groups according to gestational age at birth. Oral zinc sulfate was administered for 6 months to 49/66 children born at term, and 21/39 children born preterm. Serum zinc, IGF-1, weight, and height were measured at baseline and at 6 months. ResultsThere were no differences in baseline serum zinc levels between the two groups. In preterm NOFTT infants, zinc supplementation significantly increased serum zinc levels compared to those in the non-supplementation group (Δ zinc 0–6 month 10.3 ± 26.4 μg/dL vs. −8.8 ± 23.7 μg/dL, p = 0.018), but it did not significantly change serum IGF-1 levels or weight- and height for age Z-scores. In NOFTT infants born at term who received zinc supplementation, serum zinc levels, IGF-1, weight for age Z-score, and height for age Z-score increased at 6 months (p = 0.001, p = 0.014, p = 0.049, and p = 0.029, respectively), but this increase was not significantly greater than in the non-supplementation group. Only the increase in serum zinc levels was significant after 6 months (Δ zinc 0–6 month 16.8 ± 32.0 μg/dL vs. −10.0 ± 22.6 μg/dL, p = 0.002). ConclusionZinc supplementation in NOFTT infants improves serum zinc status, regardless of gestational age at birth. Zinc supplementation in NOFTT infants born at term may improve serum IGF-1 levels and growth, but it does not in NOFTT infants born preterm. Overall nutritional support rather than supplementation of a single nutrient may be more effective for catch-up growth in NOFTT infants born preterm.