Horm Metab Res 2019; 51(08): 503-510
DOI: 10.1055/a-0955-6662
Endocrine Care
© Georg Thieme Verlag KG Stuttgart · New York

The Effect of Zinc Supplementation on Serum Leptin Levels: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Masoud Khorshidi
1  Student Research Committee, Iran University of Medical Sciences, Tehran, Iran
,
Meysam Zarezadeh
2  Department of Cellular and Molecular Nutrition, Tehran University of Medical Sciences (TUMS), Tehran, Iran
,
Alireza Sadeghi
2  Department of Cellular and Molecular Nutrition, Tehran University of Medical Sciences (TUMS), Tehran, Iran
,
Alireza Teymouri
3  School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
,
Mohammad Reza Emami
4  Department of Nutrition, Kermanshah University of Medical Sciences, Kermanshah, Iran
,
Hamed Kord-Varkaneh
5  Student Research Committee, Department of Clinical Nutrition and Dietetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
,
Naheed Aryaeian
6  Nutrition Department, Iran University of Medical Sciences, Tehran, Iran
,
Jamal Rahmani
7  Department of Community Nutrition, Shahid Behehshti University of Medical Sciences, Tehran, Iran
,
Seyed Mohammad Mousavi
8  Department of Community Nutrition, Tehran University of Medical Sciences (TUMS), Tehran, Iran
9  Students’ Scientific Research Center (SSRC), Tehran University of Medical Sciences (TUMS), Tehran, Iran
› Author Affiliations
Further Information

Publication History

received 29 April 2019

accepted 05 June 2019

Publication Date:
13 August 2019 (online)

Abstract

Recently, obesity has become a common worldwide concern. Leptin, as an adipocytokine, plays a major role in the etiology of obesity. Prior studies have demonstrated that zinc potentially affects serum leptin levels. However, clinical trials carried out in this regard are not consistent. Therefore, current meta-analysis was conducted to ascertain the actual effect of zinc supplementation on serum leptin levels in adults. Databases of PubMed, SCOPUS, and Google Scholar were methodically searched to identify relevant articles up to April 2018. Clinical trials that examined the effect of zinc supplementation on serum leptin concentrations as outcome variables in human adults were included. The mean difference (SD) of leptin changes in the intervention and placebo groups were used to calculate the overall effect size. Totally, 663 articles were identified, of which 6 studies were eligible randomized controlled trials (RCTs) with 7 treatment arms. The analysis suggested that zinc supplementation exerts no significant effect on overall serum leptin (WMD: 0.74 ng/ml; 95% CI: −1.39 to 2.87, p=0.49). Nevertheless, sex and duration of intervention seemed to impact the extent of zinc’s influence. In trials with female subjects, zinc consumption led to a significant decrease in serum leptin level (WMD: −1.93 ng/ml; 95% CI: −3.72 to −0.14, p=0.03) as well as trials that lasted for more than 6 weeks (WMD: −1.71 ng/ml; 95% CI: −3.07 to −0.35, p=0.01), in comparison to the control group. Zinc supplementation did not significantly improve leptin concentrations, but it may result in a decreased circulating leptin level in studies with a duration of more than 6 weeks especially among females.