Abstract
BACKGROUND: Serum zinc levels decrease in chronic liver disease (CLD), but their effects on liver reserve function, tyrosine, skeletal muscle mass, handgrip strength (HGS), and hepatocellular carcinoma (HCC) development remain poorly understood. METHODS: A retrospective, cross-sectional study was conducted on 516 CLD cases. Patients were divided into a low zinc group (< 80 μg/dL) and a high zinc group (≥ 80 μg/dL). Serum zinc levels were analyzed with liver reserve function (assessed by modified albumin-bilirubin [mALBI] grade), tyrosine, branched-chain amino acid/tyrosine ratio (BTR), and HCC development. In 180 cases, the relationship between serum zinc levels and skeletal muscle characteristics, including sarcopenia and HGS, was investigated. RESULTS: Tyrosine levels increased significantly with mALBI grade progression. Patients in the low zinc group had higher tyrosine levels (76.9 vs. 67.2 μmol/L, p < 0.001), a greater proportion of high tyrosine levels (5.3% vs. 1.7%, p < 0.001), and more HCC cases (10.5% vs. 3.7%, p < 0.005). Zinc levels were lower with more severe CLD (81 μg/dL [mALBI grade 1] vs. 35.2 μg/dL [grade 3], p < 0.001). Tyrosine levels were higher in HCC patients than in non-HCC patients (93.1 vs. 70.7 μmol/L, p < 0.001). Sarcopenia prevalence did not differ between groups (56.6% vs. 52.0%, p = 0.344), but low HGS was more frequent in low zinc patients (61.2% vs. 46.3%, p = 0.032). In a subset of patients with low zinc levels (n = 12), zinc supplementation reduced tyrosine levels after 3 months (86.3 vs. 73.3 μmol/L, p = 0.017). CONCLUSION: Hypozincemia is linked to elevated tyrosine levels, reduced HGS, increased HCC incidence, and CLD progression.