Departments of Health Research and Policy (Epidemiology) and Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
Neurology. 2012 Jun 5;78(23):1841-8. doi: 10.1212/WNL.0b013e318258f822.
To determine the cognitive effects of long-term dietary soy isoflavones in a daily dose comparable to that of traditional Asian diets.
In the double-blind Women's Isoflavone Soy Health trial, healthy postmenopausal women were randomly allocated to receive daily 25 g of isoflavone-rich soy protein (91 mg of aglycone weight of isoflavones: 52 mg of genistein, 36 mg of daidzein, and 3 mg glycitein) or milk protein-matched placebo. The primary cognitive endpoint compared between groups at 2.5 years was change from baseline on global cognition, a composite of the weighted sum of 14 neuropsychological test score changes. Secondary outcomes compared changes in cognitive factors and individual tests.
A total of 350 healthy postmenopausal women aged 45-92 years enrolled in this trial; 313 women with baseline and endpoint cognitive test data were included in intention-to-treat analyses. Adherence in both groups was nearly 90%. There was no significant between-group difference on change from baseline in global cognition (mean standardized improvement of 0.42 in the isoflavone group and 0.31 in the placebo group; mean standardized difference 0.11, 95% confidence interval [CI] -0.13 to 0.35). Secondary analyses indicated greater improvement on a visual memory factor in the isoflavone group (mean standardized difference 0.33, 95% CI 0.06-0.60) but no significant between-group differences on 3 other cognitive factors or individual test scores, and no significant difference within a subgroup of younger postmenopausal women.
For healthy postmenopausal women, long-term dietary soy isoflavone supplementation in a dose comparable to that of traditional Asian diets has no effect on global cognition but may improve visual memory.
This study provides Class I evidence that long-term dietary supplementation with isoflavone-rich soy protein does not improve global cognition of healthy postmenopausal women.
确定与传统亚洲饮食中每日剂量相当的长期食用大豆异黄酮对认知的影响。
在双盲妇女异黄酮大豆健康试验中，健康绝经后妇女被随机分配接受每日 25 克富含异黄酮的大豆蛋白（91 毫克糖苷型异黄酮：52 毫克染料木黄酮，36 毫克大豆苷元和 3 毫克黄豆苷元）或牛奶蛋白匹配的安慰剂。两组之间 2.5 年的主要认知终点是从基线开始的整体认知变化，这是 14 项神经心理学测试评分变化的加权总和。次要结果比较认知因素和个别测试的变化。
共有 350 名年龄在 45-92 岁的健康绝经后妇女参加了这项试验；313 名基线和终点认知测试数据的妇女被纳入意向治疗分析。两组的依从性都接近 90%。两组之间从基线开始的整体认知变化没有显著差异（异黄酮组的平均标准化改善为 0.42，安慰剂组为 0.31；平均标准化差异为 0.11，95%置信区间[CI]为-0.13 至 0.35）。二次分析表明，异黄酮组在视觉记忆因子上的改善更大（平均标准化差异为 0.33，95%CI 为 0.06-0.60），但在其他 3 个认知因素或个别测试分数上两组之间没有显著差异，在较年轻的绝经后妇女亚组中也没有显著差异。
对于健康的绝经后妇女，长期食用与传统亚洲饮食剂量相当的大豆异黄酮补充剂对整体认知没有影响，但可能改善视觉记忆。
这项研究提供了 I 级证据，表明长期食用富含异黄酮的大豆蛋白补充剂不会改善健康绝经后妇女的整体认知。
