RESUMO
BACKGROUND: The present study aimed to evaluate the impact of animal and vegetable protein supplementation on health-related quality of life (HRQL) in patients with hepatitis C virus (HCV) and to investigate clinical and nutritional variables related to quality of life in these patients. METHODS: One hundred and forty patients infected with HCV were randomly assigned to one of two groups: the Soy Group (SG; n = 72), where patients received a soy supplement diet and the Casein Group (CG; n = 68), where patients received casein as a supplement. Anthropometric, biochemical and clinical assessments were performed in all patients, and the Short-Form Health Survey was applied at baseline and 12 weeks after study initiation. RESULTS: Before supplementation, poor HRQL scores were associated with female sex (P = 0.004) and advanced fibrosis (F3/F4; P = 0.04). Reduced HRQL scores were correlated with age (r = -0.263; P = 0.002), serum albumin levels (r = 0.245; P = 0.004), lean mass (r = 0.301; P < 0.0001) and body fat percentage (r = -0.262; P = 0.002). After 12 weeks of intervention, patients in both supplementation groups showed significantly increased HRQL scores, with no difference being observed between the SG and the CG. CONCLUSIONS: Nutritional therapy with either soybean or casein supplementation improved quality of life in patients infected with HCV. Quality of life was influenced by anthropometric, biochemical, clinical and sociodemographic factors in patients with HCV before nutritional supplementation.