中老年人群铁负荷状况及铁过载对机体红细胞氧化代谢和功能影响研究

Iron status is the level of iron reserved in the body that meets the body's physiological and metabolic need, including sufficiency, deficiency and overload, with the latter two having a bad impact on health. Iron deficiency has been prevented efficiently and the prevalence of iron deficiency anemia has decreased year by year. However, the iron overload may increase with the chronic disease, which has not aroused sufficient attention yet and the related study is deficient. In the recent years, high consumption of animal food and health care products containing iron may cause iron overload in the body. Iron overload produces large amount of free radicals in the body which may cause oxidative damage in tissue cells, particularly oxidative damage and dysfunction on erythrocytes and the membrane. There exists close relationship between iron overload and chronic disease. The middle-elderly people has high incidence of chronic disease, also with high risk of iron metabolism disorders or iron overload. The project will recruit 8500 middle-elderly persons, investigate the iron status and the correlation with chronic disease. 240 iron overload subjects will be selected randomly to detect the impact of iron overload on oxidative stress, the oxidative metabolism and function of erythrocytes. The potential health hazards of iron overload will be studied together with the early biomarkers of physiological changes. The adequate intake of iron would be proposed in this population. This study will provide scientific basis for the prevention of iron overload and the related chronic diseases.

铁负荷状况是指铁在机体内储备水平和满足机体生理功能及代谢需要的程度，可有充足、缺乏和过载，后两者均可对健康产生影响。铁缺乏及缺铁性贫血患病率已得到有效防治并呈逐年下降趋势，而铁过载可能伴随着慢性疾病呈现逐年上升，但尚未引起足够重视和缺乏相关研究。近年来，居民动物性食物消费过高、铁保健品补充过量，均可致体内铁过载；过量铁可引发机体产生大量自由基，引起组织细胞氧化损伤，尤其易致红细胞及其质膜氧化损伤及功能紊乱。铁过载与慢性病发生发展密切相关，中老年人群是慢性病高发人群，也是铁代谢紊乱或铁过载高风险人群。本项目拟调查了解8500名中老年人群铁负荷状况以及与慢性疾病的关联程度；结合动物实验，并随机抽取240名铁过载人群观察铁过载对机体氧化应激、红细胞氧化代谢及红细胞功能影响，探讨铁过载对健康潜在危害预警指标或标记物，提出该人群铁适宜摄入量，为避免铁过载危害及慢性疾病防治提供科学依据。

铁负荷状况是指铁在机体内储备水平和满足机体生理功能及代谢需要的程度，可分为充足、缺乏和过载状态，后两者均可对健康产生不良影响。铁缺乏可通过合理膳食或铁剂补充得到有效地预防和治疗；然而，近年来铁过载状况呈现逐年上升趋势并可能影响慢性疾病的发生发展。因此，开展铁负荷状况调查分析及探讨铁过载对红细胞结构和功能影响十分必要。.本研究对11860例中老年人群开展了铁负荷状况调查，分析了铁过载现状及其影响因素，红细胞组织形态学特征及红细胞能量代谢活性等功能，初步探讨了铁过载与慢性疾病关联及风险。.结果发现被调查的11860名中老年人群铁过载总检出率为8.97%，其中男性检出率为12.82%，40-50岁检出率高达15.17%；女性40~44岁铁过载仅为率1.10%，而60~65岁铁过载率上升到7.80%，由此显示铁过载问题十分严峻。.铁过载可影响红细胞的结构和功能，研究结果显示铁过载人群外周血循环红细胞衰老率达到20.3%，显著高于铁水平正常人群(11.0%)；形态学显示铁过载机体可出现大量异常红细胞，形成皱缩、体积减少、有囊泡溢出等异常老化的红细胞，可能是与铁过载氧化损伤有关。铁过载可使红细胞膜Na＋-K＋-ATP酶活性显著下降49.7%；MetHb含量增加42.57%，血清SH含量下降了38%，PK活性降低了35.8%，表明红细胞能量代谢功能发生紊乱。.铁过载影响因素调查分析发现超重、血糖异常、过量进食畜肉类为其危险因素，每天进食蔬菜为铁过载的保护因素。通过动物实验研究显示过量铁摄入可使雄性大鼠肝组织、肾组织及脑组织中的铁含量升高和氧化应激水平增强，淋巴细胞DNA损伤；铁过载可使雄性及雌性大鼠生殖能力显著下降，胚胎发育障碍，显示出明显的生殖毒性，而控制铁的摄入量可明显改善。.综上研究，铁过载在中老年人群中检出率异常增高，红细胞的异常衰老率约为正常人2倍，并出现大量结构形态异常的红细胞，严重影响了红细胞的正常生物学功能。由此提示铁过载对人体健康是有害的，建议继续开展铁过载与慢性代谢性疾病发生发展的机制及其防控措施研究。

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