Low serum zinc level is linked to hepatic encephalopathy (HE); however, the efficacy of zinc supplementation is still uncertain. The objective of the present study is to investigate the effects of zinc supplementation on HE treatment in cirrhosis patients.

MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE and Scopus from beginning to December 2018 without any publication date or language limitations. Randomized and controlled trials of zinc supplementation versus placebo or any other treatment for the treatment and management of HE in adult cirrhosis patients were selected. The primary consequence was the degree of HE as evaluated by clinical signs or specific psychometric tests. The secondary consequences included were serum ammonia levels, the length of hospital stay and expenses or adverse events.

The results of the meta-analysis of four trials with 247 patients were comprised. In cirrhosis patients having mild HE (≤ grade II), the existing evidence had suggested that the combination treatment of zinc supplementation and lactulose for 3 to 6 months significantly improves performance in the number connection test as reported in three trials (n = 227). But when compared with lactulose treatment alone, additional zinc supplementation did not show any significant difference in the digit symbol test or serum ammonia levels as reported in two trials (n = 137). No adverse events were reported in the included trials.

The study concluded that a combination of zinc supplementation and lactulose treatment over 3 to 6 months can improve the number connection test in patients with cirrhosis with low grade HE as compared with lactulose only.

Source: Shen YC, Chang YH, Fang CJ, Lin YS. Zinc supplementation in patients with cirrhosis and hepatic encephalopathy: a systematic review and meta-analysis. Nutr J. 2019 Jul 6;18(1):34. doi: 10.1186/s12937-019-0461-3. PMID: 31279342; PMCID: PMC6612144.