Seyed Mohammad Mousavi1, Maryam Hajishafiee2, Cain C T Clark3, Israel Júnior Borges do Nascimento4, Alireza Milajerdi5, Mohammad Reza Amini6, Ahmad Esmaillzadeh7. 1. Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran; Students' Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran. 2. Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia. 3. Centre for Intelligent Healthcare, Coventry University, Coventry, CV15FB, UK. 4. University Hospital and School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; School of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States. 5. Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran. 6. Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran. 7. Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran; Obesity and Eating Habits Research Center, Endocrinology and Metabolism Molecular Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran; Food Security Research Center, Department of Community Nutrition, Isfahan University of Medical Sciences, Isfahan, Iran. Electronic address: a-esmaillzadeh@tums.ac.ir.
Abstract
BACKGROUND: Oxidative stress plays an important role in the occurrence of chronic diseases. Zinc supplementation is also known to be an antioxidant agent. While, there is no review on the effects of zinc supplementation on oxidative stress, this study aimed to systematically summarize randomized clinical trials (RCTs) which have evaluated the impacts of zinc supplementation on oxidative stress biomarkers. METHODS: Systematic searches were performed using the PubMed/Medline, Scopus, and Google Scholar databases, up to April 2020. All RCTs assessed the effect of oral zinc supplementation on serum malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione (GSH), and nitric oxide (NO) levels, were included. For each variable, mean differences (MD) and standard deviations (SDs) were combined using the random-effects model, and the fractional polynomial model was used to implement the dose-response analysis. RESULTS: Ten RCTs were included. The pooled analysis of data showed that zinc supplementation significantly reduced MDA levels (MD: -0.42 μmol/L; 95 % CI: -0.71 to -0.13), increased serum TAC (MD: 225.96 mmol/L; 95 % CI: 68.42-383.5) and GSH levels (MD: 49.99 μmol/L; 95 % CI: 2.25 t 97.73), compared with the placebo group. In contrast, no significant changes were seen in NO levels following zinc supplementation (MD: -1.66 μmol/L; 95 % CI: -5.89 to 2.57). Dose-response analysis showed a significant non-linear relationship between zinc supplementation dosage and serum levels of MDA (p < 0.01), but not other biomarkers. CONCLUSIONS: The current study showed that zinc supplementation would significantly decrease MDA and increase TAC and GSH, but not NO levels. Thus, it encourages the use of zinc supplementation in oxidative stress-related diseases.
BACKGROUND: Oxidative stress plays an important role in the occurrence of chronic diseases. Zinc supplementation is also known to be an antioxidant agent. While, there is no review on the effects of zinc supplementation on oxidative stress, this study aimed to systematically summarize randomized clinical trials (RCTs) which have evaluated the impacts of zinc supplementation on oxidative stress biomarkers. METHODS: Systematic searches were performed using the PubMed/Medline, Scopus, and Google Scholar databases, up to April 2020. All RCTs assessed the effect of oral zinc supplementation on serum malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione (GSH), and nitric oxide (NO) levels, were included. For each variable, mean differences (MD) and standard deviations (SDs) were combined using the random-effects model, and the fractional polynomial model was used to implement the dose-response analysis. RESULTS: Ten RCTs were included. The pooled analysis of data showed that zinc supplementation significantly reduced MDA levels (MD: -0.42 μmol/L; 95 % CI: -0.71 to -0.13), increased serum TAC (MD: 225.96 mmol/L; 95 % CI: 68.42-383.5) and GSH levels (MD: 49.99 μmol/L; 95 % CI: 2.25 t 97.73), compared with the placebo group. In contrast, no significant changes were seen in NO levels following zinc supplementation (MD: -1.66 μmol/L; 95 % CI: -5.89 to 2.57). Dose-response analysis showed a significant non-linear relationship between zinc supplementation dosage and serum levels of MDA (p < 0.01), but not other biomarkers. CONCLUSIONS: The current study showed that zinc supplementation would significantly decrease MDA and increase TAC and GSH, but not NO levels. Thus, it encourages the use of zinc supplementation in oxidative stress-related diseases.