A Follow-up Study of the Chronic Kidney Disease Patients Treated with Brazil Nut: Focus on Inflammation and Oxidative Stress

Brazil nut is the richest known food source of selenium. The supplementation with Brazil nut during 3 months was effective in reducing oxidative stress and inflammation in hemodialysis (HD) patients. However, there are no available data on the antioxidant effect after that supplementation. The objective of this work was to determine if the beneficial effects of one Brazil nut supplementation per day during 3 months for the HD patients could be sustained after 12 months. Twenty-nine HD patients (58.6 % men, 51.0 +/- 3.3 years) from RenalCor Clinic, Rio de Janeiro, Brazil, were followed up 12 months after the supplementation study had finished. The plasma levels of antioxidant substances as selenium, glutathione peroxidase (GPx), 8-isoprostane, 8-hydroxy-2-deoxyguanosine (8-OHdG) and cytokines (tumour necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6)) were determined before, after 3 months of supplementation and after 12 months. After 3-months supplementation, cytokines, 8-OHdG and 8-isoprostane plasma levels have decreased and the activity of GPx and selenium plasma levels have increased significantly. Additionally, after 12 months, the values of 8-isoprostane, 8-OHdG and cytokines increased and the activity of GPx and selenium plasma levels decreased significantly. The levels of oxidative stress and inflammation biomarkers after 12 months increased compared to the basal levels. Consequently, it is necessary to motivate patients to adopt different dietary intake patterns.