Zinc supplementation in liver cirrhosis: meta-analysis of its effect on biochemical and clinical outcomes

Zinc deficiency is common in patients with liver cirrhosis, and the effects of zinc supplementation on cirrhosis remain controversial. This study aims to explore the effectiveness of zinc supplementation in the clinical treatment of cirrhosis and hepatic encephalopathy. MEDLINE, Embase, Cochrane Library, Scopus, Ovid, and Web of Science databases were searched with a cutoff date of March 2025. A meta-analysis of randomized controlled trials on the efficacy of zinc supplementation in the treatment of liver cirrhosis and hepatic encephalopathy was performed using RevMan5.4 and StataMP17 software. Seven studies comprising 338 patients with cirrhosis (172 patients in the treatment group and 166 patients in the control group) were included. Results indicated that zinc supplementation slightly increased serum albumin levels compared with those of the control group (WMD=0.07, 95% CI [0.00, 0.14], P=0.04). In particular, zinc supplementation dose of <50 mg and time of ≥16 weeks showed a slight advantage. Zinc supplementation also improved（alanine aminotransferase）ALT content (WMD=−8.83, 95% CI [−15.47, −2.19], P=0.009), reduced blood ammonia levels (WMD=−5.92, 95% CI [−10.52, −1.32], P=0.01), and shortened the NCT - A time (WMD = 7.31, 95% CI [-9.52, -5.09], P < 0.001). Zinc supplementation may modestly improve nutritional parameters, hepatic function, and reduce the risk of hepatic encephalopathy in patients with cirrhosis. However, some outcomes demonstrated limited clinical significance, and further research is needed to determine the optimal dosage and duration of zinc supplementation.