A critical review of vitamin C for the prevention of age-related cognitive decline and Alzheimer's disease.
A critical review of vitamin C for the prevention of age-related cognitive decline and Alzheimer's disease.
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DOI：
10.3233/jad-2012-111853
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Harrison FE
中科院分区：
文献类型：
--
作者：
Harrison FE
长期以来，人们一直认为，饮食中的抗氧化剂可以提供一定程度的保护，防止阿尔茨海默病的病理过程中涉及的氧化损伤，以及正常衰老时的一般认知能力下降。然而，文献中对这一假设的支持是模棱两可的。特别是在维生素C(抗坏血酸)方面，由于缺乏对维生素C代谢的一些具体特征的考虑，导致根据维生素C状况对参与者进行分类的研究不准确，而且由于缺乏关键信息，无法得出适当的结论。血浆中的维生素C水平并不总是被报告，从食物日记中估计的每日摄入量可能不准确或不能反映实际的血浆值。将摄入的维生素C从肠道运输到血液的能力受到可饱和的钠依赖维生素C转运体(SVCT1)的限制，因此摄入量非常高，而补充剂的使用往往被错误地认为是比实际情况更有益的。目前的综述记录了不同研究在参与者的维生素C状况方面的差异。总体而言，有大量证据表明，保持健康的维生素C水平可以预防与年龄相关的认知能力下降和阿尔茨海默病，但避免维生素C缺乏症可能比在正常、健康的饮食基础上服用补充剂更有益。
Antioxidants in the diet have long been thought to confer some level of protection against the oxidative damage that is involved in the pathology of Alzheimer’s disease as well as general cognitive decline in normal aging. Nevertheless, support for this hypothesis in the literature is equivocal. In the case of vitamin C (ascorbic acid) in particular, lack of consideration of some of the specific features of vitamin C metabolism has led to studies in which classification of participants according to vitamin C status is inaccurate, and the absence of critical information precludes the drawing of appropriate conclusions. Vitamin C levels in plasma are not always reported, and estimated daily intake from food diaries may not be accurate or reflect actual plasma values. The ability to transport ingested vitamin C from the intestines into blood is limited by the saturable sodium-dependent vitamin C transporter (SVCT1) and thus very high intakes, and the use of supplements are often erroneously considered to be of greater benefit that they really are. The current review documents differences among the studies in terms of vitamin C status of participants. Overall, there is a large body of evidence that maintaining healthy vitamin C levels can have a protective function against age-related cognitive decline and Alzheimer’s disease, but avoiding vitamin C deficiency is likely to be more beneficial than taking supplements on top of a normal, healthy diet.