Effect of Zinc Supplementation on GH, IGF1, IGFBP3, OCN, and ALP in Non-Zinc-Deficient Children

Abstract

Objective: Because most publications on growth and development deal with children with zinc deficiency, we decided to study the effects of this micronutrient on the secretion of growth hormone (GH), insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3), osteocalcin (OCN), and alkaline phosphatase (ALP) in healthy and eutrophic children. This study is original because the methodology was unique.Methods: Forty schoolchildren participated in the study, 17 females and 23 males, aged 8 and 9 years. The study was carried out during a 3-month period. It was characterized as a triple-blind randomized controlled trial. The children were divided in a control group (20 schoolchildren using 10% sorbitol) and experimental group (20 schoolchildren using zinc). All were submitted to oral zinc supplementation (10 mg Zn/day) and venous zinc administration (0.06537 mg Zn/kg of body weight). Blood samples were collected at 0, 60, 120, 180, and 210 min. All schoolchildren were also submitted to anthropometric, clinical, and dietetic assessments as well as biochemistry analyses.Results: Oral zinc supplementation in the experimental group (1) stimulated an increase in the consumption of protein and fat (p = 0.0007, p < 0.0001, p < 0.0001, respectively), (2) increased basal serum zinc (p < 0.0001), (3) increased plasma ALP (p = 0.0270), and (4) showed a positive correlation for IGF1, IGFBP3, and OCN, comparing before and after oral zinc supplementation (p = 0.0011, p < 0.0001, p < 0.0446, respectively). During zinc administration, plasma IGF1 and IGFBP3 increased significantly in the experimental group (p = 0.0468, p < 0.0001, respectively). Plasma GH increased in the experimental group but without statistical difference comparing before and after oral zinc supplementation.Conclusions: Zinc supplementation stimulated an increase in the consumption of some macronutrients and basal serum zinc and improved plasma alkaline phosphatase levels. Zinc administration increased hormones of the GH-IGF1 system.