【作者】 孙永叶；

【导师】 马爱国；

【作者基本信息】 青岛大学 ， 营养与食品卫生学， 2011， 博士

【摘要】 尽管人们的生活水平不断提高,仍有相当一部分人群维生素和矿物质等微量营养素的摄入量处在边缘缺乏甚至缺乏的状态,尤其是处在特殊生理状态的孕妇和中老年人群,是营养不良的高发人群。而有研究证实,充足的维生素和矿物质的摄入是调节机体的氧化应激水平,维持免疫系统正常功能所必需的。妊娠期妇女随着胎盘发育成熟,胎盘富含的血管暴露于高氧分压,胎盘富含的线粒体在呼吸链中释放出大量的电子,使机体氧化应激增强,免疫功能受损。而中老年人群随着年龄增长,机体抗氧化防御体系功能下降,氧化损伤加剧。因此,通过合理补充微量营养素,可以达到改善营养状况,促进健康的效果。本研究分别选取孕妇和中老年人群作为研究对象,通过补充铁、叶酸、视黄醇或维生素E(VE)等微量营养素,观察其对机体抗氧化能力及免疫功能等方面的改善作用。首先选取妊娠中期(12-24周)妇女166名,根据其血红蛋白和血清铁蛋白水平分为铁营养状况不同的4组,收集各组孕妇红细胞,制备红细胞膜。通过检测红细胞膜SOD等抗氧化酶活性、MDA水平及膜流动性等指标,对比分析不同铁营养状况孕妇的抗氧化能力。结果显示,与非贫血孕妇比较,贫血孕妇红细胞膜SOD、GSH-Px活性下降,MDA水平升高；当孕妇Hb水平超过130g/L时,其抗氧化能力和细胞功能与Hb在110～130/L的孕妇无显著差别。提示铁营养状况改善可提高机体的抗氧化能力。基于上述实验结果,又进一步观察了补充铁及维生素A对贫血孕妇铁营养状况改善及免疫功能的影响。选取妊娠中期贫血(Hb<110g/L)妇女186名,随机分为4组,分别给予安慰剂(C组)、60mg铁(I组)、60mg铁+0.4mg叶酸(IF组)、60mg铁+0.4mg叶酸+2.0mg视黄醇(IFR组)补充2个月,分别检测各组孕妇Hb、血浆铁蛋白、VA、叶酸等营养状况指标及IL-2、淋巴细胞增殖活性等免疫指标。结果发现3个营养素补充组铁营养状况均明显改善,IL-2水平、淋巴细胞增殖活性也明显提高。而且联合补充铁、叶酸和视黄醇组孕妇铁营养状况及免疫功能均较单独补铁组改善效果好。可见,补充铁、VA等微量营养素可有效改善贫血孕妇营养状况,并促进机体免疫功能。因此,我们又针对中老年人群易发生营养不良的生理特点,继续观察了补充VE对中老年人群抗氧化能力的改善效果。选取55-70岁的中老年人180名,随机分为：安慰剂对照组和100、200、300 mg/d VE补充组,干预时间4个月。干预前后分别采集空腹静脉血,分离血浆和红细胞,同时制备红细胞膜。检测各组血浆SOD、MDA等指标,并分析红细胞溶血度及膜流动性。结果表明每天补充100、200和300mg VE组血浆VE水平明显升高,脂质过氧化产物(MDA)生成减少,而SOD活性也降低,但3组间无显著差异。与对照组比较,每天补充200和300mg VE可有效降低红细胞溶血度,提高红细胞膜流动性。综上可见,缺铁性贫血会导致孕妇细胞抗氧化能力和细胞功能降低,随着铁营养状况的改善,孕妇抗氧化能力逐渐升高,细胞功能改善；当孕妇Hb≥130g/L时,抗氧化能力和细胞功能与Hb值在110～130g/L的孕妇比较并无明显差异。对贫血孕妇联合补充铁、叶酸和视黄醇比单独补铁更有利于改善铁营养状况,提高IL-2水平和淋巴细胞增殖活性。对于中老年人群,每天补充100～300mg维生素E可有效减轻机体的氧化损伤,200～300mg/d VE还可明显改善红细胞膜功能。更多还原

【Abstract】 Although there is a rising of living standards, the intake of vitamins and minerals of large parts of the population are marginally adequate, or even clearly deficient, especially pregnant women and middle-aged and elderly people, who are in special physiological status have higer risk of malnutrition. It’s proved that adequate intakes of vitamins and trace elements are required for regulating oxidative stress and the immune system to function efficiently. During pregnancy, as the placenta matures, its vascular exposes to high maternal oxygen partial pressure and its abundant mitochondrial mass favors the production of reactive oxygen species (ROS). So, the oxidative stress increases and immune function is damaged. With age, the antioxidative activity decreases and oxidative damage exacerbates. Therefore, micronutrients supplementation can improve nutrition status and promote health. This study chose the above two population as subjects, and investigated the improvement in antioxidative activity and immune function after supplementation with iron, folic acid, retinol or vitamin E.First,166 pregnant women (12-24w gestation) were randomized into 4 groups according to the Hb and serum ferritin levels. Erythrocytes of each group were collected and erythrocyte membrane was prepared. Indicators including SOD, MDA and fliudity of erythrocyte membrane et al. were measured, the results showed that compared with the non-anemic pregnant women, activities of SOD and GSH-Px of erythrocyte membrane in anemic pregnant women decreased, the level of MDA increased and the membrane fliudity also decreased. For those pregnant women whose Hb levels are more than 130g/L, the antioxidative activity and cell function have no significant difference compared with those pregnant women whose Hb levels are 110-130 g/L. It is indicated that with the improvement of iron status, the antioxidative activity increased. Based on the above results, we further investigated the effect of iron and retinol supplementation on iron status and immune function of anemic pregnant women. We randomly allocated 186 anemic pregnant women(12-24w gestation) into four groups. Group C was the placebo group, I was supplemented daily with 60 mg iron as ferrous sulfate, IF with 60 mg iron and 0.4 mg folic acid, IFR with 60 mg iron,0.4 mg folic acid and 2.0 mg retinol. Nutrition status biomarkers including hemoglobin concentration, erythrocyte protoporphyrin (EP), plasma ferritin, plasma retinol, plasma folic acid and immune indexes including IL-2 and lymphocyte proliferation were measured. After the 2 months trial, compared with group C, there were considerable increases of iron status in Hb and plasma ferritin in the I, IF and IFR groups, IL-2 levels and lymphocyte proliferation also increased significantly. Iron combined folic acid and retinol supplementation was more beneficial to improving iron status and immune function during pregnancy than iron alone. This shows that micronutrients (iron, retinol, et al.) supplementation can effectively improve nutrition status of anemic pregnant women and promote the immune function. Taking the elderly population’s physiological characteristics into account, they are vulnerable to malnutrition. Therefore, we analyzed the effect of vitamin E supplementation on the antioxidant capacity in the elderly population.180 middle-aged and elderly people(55-70 yrs) were randomly allocated into 4 groups:placebo control group and 100,200,300mg/d VE supplement groups. The intervention period was 4 months. Plasma and erythrocyte membrane were collected for measurement at baseline and after the intervention. The concentration of plasma MDA and activity of plasma SOD were determined. Erythrocyte hemolysis and membrane fluidity were detected too. The plasma VE concentration increased significantly in the three VE supplement groups after 4 months of supplementation. Plasma MDA was reduced and SOD activity was reduced too, while there were no significant differences between the three supplement groups. Compared with group C,200 or 300mg/d VE supplementation decreased erythrocyte hemolysis and elevated erythrocyte membrane fliudity.Results of these studies confirmed that IDA (Hb<110g/L) can decrease antioxidative activity and cell functions of pregnant women. With the improvement of iron status, the antioxidative activity and cell functions of pregnant women are increased gradually. The high level of hemoglobin which is above 130g/L does not have additional effect on the antioxidative activity and cell functions. Iron combined folic acid and retinol supplementation was more beneficial to improving iron status, IL-2 and lymphocyte proliferation during pregnancy than iron alone. For middle-aged and elderly people, supplementation of 100-300mg/d VE can effectively alleviate oxidative damage and 200-300mg/d VE can improve erythrocyte function.更多还原