Hypertension：黄烷醇可改善老年认知功能

8月14日，在线发表于《高血压》杂志（<em>Hypertension</em>）的意大利一项研究显示，有规律地通过膳食补充可可黄烷醇可能会提高老年轻度认知障碍患者的认知功能，且这种作用可能部分受胰岛素敏感性提高影响。

纳入研究的90例患有轻度认知功能障碍的老年患者被随机分为3组，分别通过饮食补充高含量（≈990 mg）、中等含量（≈520 mg）和低含量（≈45 mg）的黄烷醇饮品，每天一次，共8周。随访发现，3组患者简易精神状态量表结果相似。高含量组和中等含量组患者完成连线试验A和B时间显著短于低含量组，且高含量组患者语言流畅性测验结果显著优于低含量组。此外，高含量和中等含量组患者胰岛素抵抗、血压升高及脂质过氧化等得以显著改善。

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<br/><strong>专家点评</strong><br/>


复旦大学附属华东医院临床营养中心孙建琴教授：黄烷醇类化合物是一种天然抗氧化剂，具有清除体内自由基、减少组织细胞氧化损伤的作用。其主要来源有茶、葡萄、红酒、苹果、含可可的食品（包括巧克力）等。

该研究是第一个通过膳食补充黄烷醇的途径来研究其对老年认知功能障碍作用的研究，试验结果显示，可可黄烷醇对改善轻度认知障碍高龄患者的认知功能、血压及胰岛素抵抗、降低脂质过氧化反应存在积极作用，且存在一定量效关系。最近也有其他研究显示，可可黄烷醇可增加大脑血流量、改善血管功能、降低血压、降低血液中低密度脂蛋白水平及改善认知功能。

该研究样本数量较大，时间较长，是一设计良好的随机平行对照临床研究，为通过膳食补充可可黄烷醇改善轻度认知障碍高龄患者的认知功能提供了最新循证证据。但由于该试验选择的受试者都是不肥胖、近来不吸烟、处于良好健康状态（除轻度认知障碍以外）、未患心血管疾病的老年人，在人群选择上存在一定偏倚，使其结果缺乏代表性，难以推广到所有认知障碍老年患者。

由于黄烷醇具有清除自由基、增加大脑血流量、改善血管功能、降低血压、改善认知功能等作用，可能对改善老年人的抑郁、焦虑，甚至老年痴呆具有一定临床应用前景。目前研究不多，尚须更多大样本的临床研究来支持其临床应用。
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<img src="http://www.bioon.com/biology/UploadFiles/201208/2012082621103489.gif" alt="" width="113" height="149" border="0" hspace="0" />

<a title="" href="http://dx.doi.org/10.1161/HYPERTENSIONAHA.112" target="_blank">doi:10.1161/HYPERTENSIONAHA.112</a>
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<br/><strong>Benefits in Cognitive Function, Blood Pressure, and Insulin Resistance Through Cocoa Flavanol Consumption in Elderly Subjects With Mild Cognitive Impairment: The Cocoa, Cognition, and Aging (CoCoA) Study.</strong><br/>


Desideri G, Kwik-Uribe C, Grassi D, Necozione S, Ghiadoni L, Mastroiacovo D, Raffaele A, Ferri L, Bocale R, Lechiara MC, Marini C, Ferri C.

Abstract

Flavanol consumption is favorably associated with cognitive function. We tested the hypothesis that dietary flavanols might improve cognitive function in subjects with mild cognitive impairment. We conducted a double-blind, parallel arm study in 90 elderly individuals with mild cognitive impairment randomized to consume once daily for 8 weeks a drink containing ≈990 mg (high flavanols), ≈520 mg (intermediate flavanols), or ≈45 mg (low flavanols) of cocoa flavanols per day. Cognitive function was assessed by Mini Mental State Examination, Trail Making Test A and B, and verbal fluency test. At the end of the follow-up period, Mini Mental State Examination was similar in the 3 treatment groups (P=0.13). The time required to complete Trail Making Test A and Trail Making Test B was significantly (P&lt;0.05) lower in subjects assigned to high flavanols (38.10±10.94 and 104.10±28.73 seconds, respectively) and intermediate flavanols (40.20±11.35 and 115.97±28.35 seconds, respectively) in comparison with those assigned to low flavanols (52.60±17.97 and 139.23±43.02 seconds, respectively). Similarly, verbal fluency test score was significantly (P&lt;0.05) better in subjects assigned to high flavanols in comparison with those assigned to low flavanols (27.50±6.75 versus 22.30±8.09 words per 60 seconds). Insulin resistance, blood pressure, and lipid peroxidation also decreased among subjects in the high-flavanol and intermediate-flavanol groups. Changes of insulin resistance explained ≈40% of composite z score variability through the study period (partial r(2)=0.4013; P&lt;0.0001). To the best of our knowledge, this is the first dietary intervention study demonstrating that the regular consumption of cocoa flavanols might be effective in improving cognitive function in elderly subjects with mild cognitive impairment. This effect appears mediated in part by an improvement in insulin sensitivity.

<br/>来源：中国医学论坛报

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