University of São Paulo, Faculty of Pharmaceutical Sciences, São Paulo, Brazil.
Nutrition. 2010 Nov-Dec;26(11-12):1065-9. doi: 10.1016/j.nut.2009.08.006. Epub 2009 Dec 16.
In patients who have undergone hemodialysis, large amounts of reactive oxygen species (ROS) are produced and, at higher concentrations, ROS 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 selenium is the Brazil nut (Bertholletia excelsa, family Lecythidaceae), found in the Amazon region. We evaluated the effect of Brazil nut supplementation on blood levels of Se and glutathione peroxidase (GSH-Px) activity in patients on hemodialysis.
A total of 81 patients on hemodialysis (52.0±15.2 y old, average time on dialysis 82.3±91.4 mo, body mass index 24.9±4.4 kg/m(2)) from the RenalCor and RenalVida Clinics in Rio de Janeiro, Brazil, were studied. All patients received one nut (around 5 g, averaging 58.1 μg Se/g) a day for 3 mo. The Se concentrations in the nuts and in plasma and erythrocytes were determined by atomic absorption spectrophotometry with hydride generation (Hitachi, Z-500). GSH-Px levels were measured using Randox commercial kits.
Plasma Se (18.8±17.4 μg/L) and erythrocyte (72.4±37.9 μg/L) levels were below the normal range before nut supplementation. After supplementation, the plasma level increased to 104.0±65.0 μg/L and erythrocytes to 244.1±119.5 μg/L (P<0.0001). The activity of GSH-Px also increased after supplementation, from 46.6±14.9 to 55.9±23.6 U/g of hemoglobin (P<0.0001). Before supplementation, 11% of patients had GSH-Px activity below the normal range (27.5-73.6 U/g of hemoglobin). After supplementation, all patients showed GSH-Px activity within the normal range.
The data revealed that the investigated patients presented Se deficiency and that the consumption of only one Brazil nut a day (5 g) during 3 mo was effective to increase the Se concentration and GSH-Px activity in these patients, thus improving their antioxidant status.
在接受血液透析的患者中，会产生大量的活性氧（ROS），而在较高浓度下，ROS 被认为与心血管疾病的发病机制有关。有人提出，硒（Se）可以通过减少氧化应激来发挥抗动脉粥样硬化作用。硒含量最丰富的已知食物来源是巴西坚果（Bertholletia excelsa，隶属于 Lecythidaceae 科），生长在亚马逊地区。我们评估了巴西坚果补充剂对血液透析患者硒和谷胱甘肽过氧化物酶（GSH-Px）活性的影响。
我们研究了来自巴西里约热内卢的 RenalCor 和 RenalVida 诊所的 81 名血液透析患者（52.0±15.2 岁，平均透析时间 82.3±91.4 个月，体重指数 24.9±4.4kg/m2）。所有患者每天接受一粒坚果（约 5 克，平均含 58.1μg Se/g），持续 3 个月。使用日立 Z-500 型氢化物发生原子吸收分光光度法测定坚果、血浆和红细胞中的硒浓度。使用 Randox 商业试剂盒测量 GSH-Px 水平。
在补充坚果之前，患者的血浆硒（18.8±17.4μg/L）和红细胞硒（72.4±37.9μg/L）水平低于正常范围。补充后，血浆水平增加到 104.0±65.0μg/L，红细胞增加到 244.1±119.5μg/L（P<0.0001）。补充后 GSH-Px 活性也从 46.6±14.9 增加到 55.9±23.6 U/g 血红蛋白（P<0.0001）。在补充前，11%的患者 GSH-Px 活性低于正常范围（27.5-73.6 U/g 血红蛋白）。补充后，所有患者的 GSH-Px 活性均在正常范围内。
数据显示，研究中的患者存在硒缺乏，每天仅食用 1 个巴西坚果（5 克）持续 3 个月可有效增加患者体内的硒浓度和 GSH-Px 活性，从而改善其抗氧化状态。
