Effects of carnosine and histidine-containing dipeptides on biomarkers of inflammation and oxidative stress: a systematic review and meta-analysis

Context Carnosine and histidine-containing dipeptides (HCDs) are suggested to have anti-inflammatory and antioxidative benefits, but their effects on circulating adipokines and inflammatory and oxidative stress biomarkers remain unclear.Objectives The aim of the present systematic review and meta-analysis was to determine the impact of HCD supplementation on inflammatory and oxidative stress biomarkers.Data Sources A systematic search was performed on Medline via Ovid, Scopus, Embase, ISI Web of Science, and the Cochrane Library databases from inception to 25 January 2023.Data Extraction Using relevant key words, trials investigating the effects of carnosine/HCD supplementation on markers of inflammation and oxidative stress, including C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), adiponectin, malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), total antioxidant capacity (TAC), and catalase (CAT) were identified. Meta-analyses were conducted using random-effects models to calculate the weighted mean differences (WMDs) and 95% confidence intervals (CIs).Data Analysis A total of 9 trials comprising 350 participants were included in the present meta-analysis. Carnosine/HCD supplementation led to a significant reduction in CRP (WMD: -0.97 mg/L; 95% CI: -1.59, -0.36), TNF-alpha (WMD: -3.60 pg/mL; 95% CI: -7.03, -0.18), and MDA (WMD: -0.34 mu mol/L; 95% CI: -0.56, -0.12) and an elevation in CAT (WMD: 4.48 U/mL; 95% CI: 2.43, 6.53) compared with placebo. In contrast, carnosine/HCD supplementation had no effect on IL-6, adiponectin, GSH, SOD, and TAC levels.Conclusion Carnosine/HCD supplementation may reduce inflammatory and oxidative stress biomarkers, and potentially modulate the cardiometabolic risks associated with chronic low-grade inflammation and lipid peroxidation.Systematic Review Registration PROSPERO registration no. CRD42017075354.