Effect of Brazil nut (Bertholetia excelsa H.B.K) supplementation on biomarkers of oxidative stress, inflamatory citocines and their relation with the Pro198Leu polymorphism in glutatione peroxidase gene in patients with rheumatoid arthritis

Abstract

Rheumatoid arthritis is a inflammatory disease characterized by joints inflammation and is manifested by swelling and functional disability.The patology of the diseasse envolves an overproduction of free radicals by activated neutrophil that may induce lipid peroxidation in cell membrane which leads to increased inflammation.Thereby, selenium (main source is brazil nut)is an important factor because decreases the hydroperoxide amount through the action of the antioxidant enzyme glutathione peroxidase. Nevertheless, studies that evaluate an association between nutritional selenium status with oxidative stress and inflammatory biomarkers are scarce in the literature. Accordingly, assessing the in vivo potential effect of brazil nut supplementation as selenium source on the parameters described above and their relationship with the Pro198Leu polymorphism in the gene of GPx1 in patients with rheumatoid arthritis, come to fill this gap. This study is longitudinal in nature and crossover.Two groups of patients will participate, being constituted of rheumatoid arthritis individuals attending clinical treatment in the Federal University from Sao Paulo. A group of 35 patients will receive an unit of brazil nut supplementation a day for two months and the other without supplementation. After intervention period, both groups will pass for a three month wash out period and then will be realized the crossover between the groups. Biochemical parameters such as selenium status, oxidative stress, inflammation biomarkers, besides the determination of Pro198Leu polymorphism in the glutahione peroxidase 1 gene will be assessed.The assessment of body composition will be done through bioimpedance analysis, weight and stature measures. Food consumption will be evaluated using three days of food records and their analysis through nutwin software from Paulista School of medicine. (AU)