OBJECTIVES: To investigate the effects of a Brazil nut-enriched diet on the wall thickness and the left ventricular chamber diameter of the heart, and lipid peroxidation in a CKD-induced model. METHODS: Male Wistar rats at 12 weeks of age were divided into two groups (n=16/group): the Nx group, which underwent 5/6 nephrectomy, and the Sham group, as a control. After 5 weeks, the groups were subdivided according to diet (n=8/group): the Nx and Sham groups received a control diet; the Nx5% and Sham5% groups received a diet enriched with 5 % Brazil nuts for 8 weeks. The left ventricular thickening and chamber diameter were determined. Plasma biochemical parameters were evaluated. Analysis of thiobarbituric acid reactive substances (TBARS) and antioxidant enzyme activity was performed in the plasma and the left ventricle (LV). LV mRNA expression of nuclear factor-kappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2) was evaluated by reverse transcription-polymerase chain reaction. RESULTS: The Nx5% group showed a remodeled LV wall with decreased thickness compared to the Nx group (p=0.016). Furthermore, LV TBARS concentration was reduced in the Nx5% group (p=0.0064). In addition, the Nx5% group showed an increase in plasma GPx activity (p=0.0431). No significant results were found concerning the LV mRNA expression of NF-κB and Nrf2 genes. CONCLUSIONS: A Brazil nut-enriched diet decreased LV thickness and LV TBARS concentration and increased GPx activity in a 5/6 nephrectomy experimental model, making it a promising adjuvant therapy to improve antioxidant status and cardiovascular outcomes in chronic kidney disease.