Effects of zinc supplementation on inflammatory biomarkers and oxidative stress in adults: A systematic review and meta-analysis of randomized controlled trials

• Published in: Journal of trace elements in medicine and biology 2021-12, Vol.68, p.126857-126857, Article 126857
• Main Authors: Mohammadi, Hamed, Talebi, Sepide, Ghavami, Abed, Rafiei, Masoumeh, Sharifi, Shima, Faghihimani, Zahra, Ranjbar, Golnaz, Miraghajani, Maryam, Askari, Gholamreza
• Format: Article
• Language: English
• Subjects: Biomarkers - metabolism; C-Reactive Protein - metabolism; Dietary Supplements; Inflammation; Meta-analysis; Oxidative Stress; Randomized Controlled Trials as Topic; Zinc
• ISSN: 0946-672X; 1878-3252
• DOI: 10.1016/j.jtemb.2021.126857

Current evidence is debatable regarding the feasible effects of zinc supplementation on the inflammation and oxidative stress status of adults. This systematic review and meta-analysis aimed to clarify this inconclusiveness. Literature search was conducted via online databases such as PubMed, Scopus, ISI Web of Science, Cochrane Library, and Google Scholar until June 2020. The overall effect was presented as the weighted mean difference (WMD) at 95 % confidence interval (CI) in a random-effects meta-analysis model. Publication bias was also assessed using Egger’s and Begg’s statistics. In total, 25 clinical trials (n = 1428) were reviewed, which indicated that zinc supplementation significantly affects the concentration of C- reactive protein (WMD: -0.03 mg/l; 95 % CI: -0.06, 0.0; P = 0.029), interlukin-6 (WMD: -3.81 pg/mL; 95 % CI: -6.87, -0.76; P = 0.014), malondialdehyde (WMD: -0.78 μmol/l; 95 % CI: -1.14, -0.42; P < 0.001), and total antioxidant capacity (WMD: 95.96 mmol/l; 95 % CI: 22.47, 169.44; P = 0.010). In addition, a significant between-study heterogeneity and a non-significant increment was reported in nitric oxide (WMD: 1.47 μmol/l; 95 % CI: -2.45, 5.40; P = 0.461) and glutathione (WMD: 34.84 μmol/l; 95 % CI: -5.12, 74.80; P = 0.087). According to the results, zinc supplementation may have beneficial anti-inflammatory and anti-oxidative effects in adults.