The influence of zinc supplementation on IGF-1 levels in humans: A systematic review and meta-analysis

• Published in: Journal of King Saud University. Science Vol. 32; no. 3; pp. 1824 - 1830
• Main Authors: Guo, Jian, Xie, Jingbo, Zhou, Bo, Găman, Mihnea-Alexandru, Kord-Varkaneh, Hamed, Clark, Cain C.T., Salehi-Sahlabadi, Ammar, Li, Yunkai, Han, Xianzhang, Hao, Youguo, Liang, Yimin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2020; Elsevier
• Subjects: Humans; IGF-1; Meta-analysis; Zinc; IGF-1; Humans; Zinc; Meta-analysis
• ISSN: 1018-3647
• DOI: 10.1016/j.jksus.2020.01.018

The effect of supplementation with zinc on levels of IGF-1 remains relatively unexplored, and many of previous studies have reported equivocal findings. Thus, the aim of this study was to elucidate the influence of zinc on IGF-1. A complete systematic search was executed in Scopus, Web of Science, Embase, and PubMed/MEDLINE, by reviewers, from database inception until June 2019. Weighted mean difference (WMD) with the 95% CI was used for assessing the effects of zinc on IGF-1. We evaluated between study heterogeneity using the I-squared and the Q-test statistic. Ten studies reported changes in plasma levels of IGF-1. Combined results ascertained an increase in IGF-1 levels following zinc administration (WMD: 8.620 ng/ml, 95% CI: 1.126, 16.113, I2 = 97.3%). Subgroup analyses demonstrated that zinc intake dosage ≤10 mg/day (WMD: 9.50 ng/ml, 95% CI: 1.47, 17.53) and intervention length ˃8 weeks (WMD: 10.08 ng/ml, 95% CI: 0.67, 19.48) significantly greater increased IGF-1 levels. The present study demonstrated that zinc supplementation can elicit significant increases in IGF-1 in humans. In addition, greater increments were observed when zinc intake dosage was ≤10 mg/day and intervention duration ˃8 weeks.