Serum zinc level and dietary zinc intake status in non-alcoholic fatty liver disease: A meta-analysis and systematic review

BACKGROUND AND AIM: Non-alcoholic fatty liver disease (NAFLD) is a common health problem related to diet and a sedentary lifestyle. Zinc has essential roles in diabetes, insulin resistance and inflammation. This meta-analysis aims to evaluate the relationship between NAFLD and dietary zinc intake/serum zinc levels. MATERIALS AND METHODS: A systematic search was performed in PubMed, Web of Science, and Scopus databases for relevant English articles with mean/standard deviation values of serum zinc levels (µg/dL) and dietary zinc intake (mg/day) up to February 2020. We screened “fatty liver disease” and “zinc” keywords; totally 864 articles, eight of them were found to have suitable serum zinc level or daily zinc intake data for meta-analysis. RESULTS: Serum zinc level in NAFLD patients were lower than healthy controls (data from 984 individuals, FEM, p<0.00001). The meta-analysis results of the nutritional zinc intake of totally 19438 individuals were similar in NAFLD and control groups (FEM, p=0.36). CONCLUSION: Serum zinc levels were lower in NAFLD patients, even though they have similar zinc intake in the diet, which suggests that there may be an absorption problem or increased need, with a distributional disorder which results in lower serum zinc levels. Further studies need to evaluate the role of zinc in NAFLD.