Effect of Brazil nut supplementation on plasma levels of selenium in hemodialysis patients: 12 months of follow-up.

BACKGROUND: Large amounts of reactive oxygen species are produced in hemodialysis (HD) patients, and, at higher concentrations, reactive oxygen species are thought to be involved in the pathogenesis of cardiovascular disease. It has been proposed that selenium (Se) may exert an antiatherogenic influence by reducing oxidative stress. The richest known food source of Se is the Brazil nut (Bertholletia excelsa, family Lecythidaceae), found in the Amazon region. OBJECTIVE: The objective of this work was to determine if Se plasma levels in HD patients submitted to a program of supplementation during 3 months with 1 Brazil nut by day could be sustained after 12 months. METHODS: A total of 21 HD patients (54.2 ± 15.2 years old; average time on dialysis, 82.3 ± 51.6 months; body mass index, 24.4 ± 3.8 kg/m(2)) from the RenalCor Clinic in Rio de Janeiro, Brazil, were followed up 12 months after the supplementation study ended. The Se plasma levels were determined by atomic absorption spectrophotometry with hydride generation. RESULTS: The Se Plasma levels (17.3 ± 19.9 µg/L) were below the normal range (60 to 120 µg/L) before nut supplementation, and after 3 months of supplementation, the levels increased to 106.8 ± 50.3 µg/L (P < .0001). Twelve months after supplementation, the plasma Se levels decreased to 31.9 ± 14.8 µg/L (P < .0001). CONCLUSIONS: The data showed that these patients were Se deficient and that the consumption of Brazil nut was effective to increase the Se parameters of nutritional status. Se levels 12 months after the supplementation period were not as low as presupplementation levels but yet significantly lower, and we needed to motivate patients to adopt different dietary intake patterns.