The Influence Of Dietary Zinc Supplementation On The Expression Of Insulin-Like Growth Factor 1 (Igf-1) In Adolescent Athletes

https://doi.org/10.5281/zenodo.19438363

Abstract

Adolescence represents a critical window for growth and neuromuscular maturation, during which the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis plays a central role in promoting anabolic signaling, protein synthesis, and skeletal muscle hypertrophy. Zinc (Zn²⁺) is an essential trace element involved in growth hormone receptor signaling and transcriptional regulation of IGF-1. Despite evidence in general populations, the impact of zinc supplementation on IGF-1 expression and functional performance in adolescent athletes remains underexplored. This double-blind, randomized controlled trial investigated the effects of 12-week oral zinc supplementation (25 mg/day) on serum IGF-1, IGF binding protein-3 (IGFBP-3), creatine kinase (CK), and neuromuscular performance indices, including vertical jump height and handgrip strength, in 60 adolescent athletes (aged 14–17 years). Results demonstrated significant elevations in serum IGF-1 (p < 0.005) and IGFBP-3 (p < 0.005), accompanied by reductions in CK levels (p = 0.012) and enhanced vertical jump and handgrip performance compared to placebo. Serum zinc positively correlated with IGF-1 (r = 0.69, p < 0.001) and vertical jump height (r = 0.72, p < 0.001). Mechanistically, zinc may enhance growth hormone receptor binding, stabilize circulating IGF-1, and support muscular recovery. These findings suggest that dietary zinc supplementation is a safe and effective strategy to optimize endocrine function, neuromuscular performance, and recovery in adolescent athletes.