8月14日,，在線發(fā)表于《高血壓》雜志（Hypertension）的意大利一項研究顯示，有規(guī)律地通過膳食補充可可黃烷醇可能會提高老年輕度認(rèn)知障礙患者的認(rèn)知功能,，且這種作用可能部分受胰島素敏感性提高影響,。
納入研究的90例患有輕度認(rèn)知功能障礙的老年患者被隨機分為3組，分別通過飲食補充高含量（≈990 mg）,、中等含量（≈520 mg）和低含量（≈45 mg）的黃烷醇飲品,，每天一次，共8周,。隨訪發(fā)現(xiàn),，3組患者簡易精神狀態(tài)量表結(jié)果相似。高含量組和中等含量組患者完成連線試驗A和B時間顯著短于低含量組,，且高含量組患者語言流暢性測驗結(jié)果顯著優(yōu)于低含量組,。此外，高含量和中等含量組患者胰島素抵抗,、血壓升高及脂質(zhì)過氧化等得以顯著改善,。
專家點評
復(fù)旦大學(xué)附屬華東醫(yī)院臨床營養(yǎng)中心孫建琴教授：黃烷醇類化合物是一種天然抗氧化劑，具有清除體內(nèi)自由基,、減少組織細(xì)胞氧化損傷的作用,。其主要來源有茶、葡萄,、紅酒,、蘋果、含可可的食品（包括巧克力）等,。
該研究是第一個通過膳食補充黃烷醇的途徑來研究其對老年認(rèn)知功能障礙作用的研究,，試驗結(jié)果顯示，可可黃烷醇對改善輕度認(rèn)知障礙高齡患者的認(rèn)知功能,、血壓及胰島素抵抗,、降低脂質(zhì)過氧化反應(yīng)存在積極作用，且存在一定量效關(guān)系,。最近也有其他研究顯示,，可可黃烷醇可增加大腦血流量、改善血管功能,、降低血壓,、降低血液中低密度脂蛋白水平及改善認(rèn)知功能。
該研究樣本數(shù)量較大,，時間較長,，是一設(shè)計良好的隨機平行對照臨床研究，為通過膳食補充可可黃烷醇改善輕度認(rèn)知障礙高齡患者的認(rèn)知功能提供了最新循證證據(jù)。但由于該試驗選擇的受試者都是不肥胖,、近來不吸煙、處于良好健康狀態(tài)（除輕度認(rèn)知障礙以外）,、未患心血管疾病的老年人,，在人群選擇上存在一定偏倚，使其結(jié)果缺乏代表性,，難以推廣到所有認(rèn)知障礙老年患者,。
由于黃烷醇具有清除自由基、增加大腦血流量,、改善血管功能,、降低血壓、改善認(rèn)知功能等作用,，可能對改善老年人的抑郁,、焦慮，甚至老年癡呆具有一定臨床應(yīng)用前景,。目前研究不多,，尚須更多大樣本的臨床研究來支持其臨床應(yīng)用。（生物谷Bioon.com）
doi:10.1161/HYPERTENSIONAHA.112
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PMID:
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.
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<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<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<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.
