Staehelin Hannes B
Geriatric University Clinic, University Hospital, Basel, Switzerland.
Proc Nutr Soc. 2005 Nov;64(4):565-70. doi: 10.1079/pns2005459.
The current high life expectancy is overshadowed by neurodegenerative illnesses that lead to dementia and dependence. Alzheimer's disease (AD) is the most common of these conditions, and is considered to be a proteinopathy, with amyloid-beta42 as a key factor, leading via a cascade of events to neurodegeneration. Major factors involved are oxidative stress, perturbed Ca homeostasis and impaired energy metabolism. Protection against oxidative stress by micronutrients (including secondary bioactive substances) has been shown in transgenic Alzheimer model systems to delay AD. Epidemiological evidence is less conclusive, but the vast majority of the evidence supports a protective effect on cognitive functions in old age and AD. Thus, a diet rich in fruits and vegetables but also containing meat and fish is the most suitable to provide adequate micronutrients. The strong link between cardiovascular risk and AD may be explained by common pathogenetic mechanisms mediated, for example, by homocysteine and thus dependant on B-vitamins (folate and vitamins B(12) and B(6)). However, micronutrients may also be harmful. The high affinity of amyloid for metals (Fe, Al and Zn) favours the generation of reactive oxygen species and triggers an inflammatory response. Micronutrients in a balanced diet have a long-lasting, albeit low, protective impact on brain aging, hence prevention should be life long.
目前较高的预期寿命因导致痴呆和生活不能自理的神经退行性疾病而蒙上阴影。阿尔茨海默病（AD）是这些病症中最常见的一种，被认为是一种蛋白质病，β淀粉样蛋白42是关键因素，通过一系列事件导致神经退行性变。主要涉及的因素有氧化应激、钙稳态紊乱和能量代谢受损。在转基因阿尔茨海默病模型系统中已表明，微量营养素（包括次生生物活性物质）对氧化应激的保护作用可延缓AD的发展。流行病学证据不太确凿，但绝大多数证据支持其对老年人认知功能和AD具有保护作用。因此，富含水果和蔬菜、同时也包含肉类和鱼类的饮食最适合提供充足的微量营养素。心血管疾病风险与AD之间的紧密联系可能是由例如同型半胱氨酸介导的共同致病机制所解释的，因此依赖于B族维生素（叶酸、维生素B12和B6）。然而，微量营养素也可能有害。淀粉样蛋白对金属（铁、铝和锌）的高亲和力有利于活性氧的产生并引发炎症反应。均衡饮食中的微量营养素对大脑衰老具有长期的、尽管程度较低的保护作用，因此预防应贯穿一生。
