Yale University, Griffin Prevention Research Center, 130 Division Street, Derby, CT 06418, USA.
J Am Coll Nutr. 2012 Dec;31(6):415-23. doi: 10.1080/07315724.2012.10720468.
Metabolic syndrome is a precursor of diabetes and cardiovascular disease (CVD). Walnut ingestion has been shown to reduce CVD risk indices in diabetes. This randomized controlled crossover trial was performed to investigate the effects of daily walnut consumption on endothelial function and other biomarkers of cardiac risk in a population of overweight individuals with visceral adiposity.
Forty-six overweight adults (average age, 57.4 years; 28 women, 18 men) with elevated waist circumference and 1 or more additional signs of metabolic syndrome were randomly assigned to two 8-week sequences of walnut-enriched ad libitum diet and ad libitum diet without walnuts, which were separated by a 4-week washout period. The primary outcome measure was the change in flow-mediated vasodilation (FMD) of the brachial artery. Secondary measures included serum lipid panel, fasting glucose and insulin, Homeostasis Model Assessment-Insulin Resistance values, blood pressure, and anthropometric measures.
FMD improved significantly from baseline when subjects consumed a walnut-enriched diet as compared with the control diet (1.4% ± 2.4% versus 0.3% ± 1.5%; p = 0.019). Beneficial trends in systolic blood pressure reduction were seen, and maintenance of the baseline anthropometric values was also observed. Other measures were unaltered.
Daily ingestion of 56 g of walnuts improves endothelial function in overweight adults with visceral adiposity. The addition of walnuts to the diet does not lead to weight gain. Further study of the potential role of walnut intake in diabetes and CVD prevention is warranted.
代谢综合征是糖尿病和心血管疾病（CVD）的前兆。核桃的摄入已被证明可以降低糖尿病患者的 CVD 风险指数。本随机对照交叉试验旨在研究超重伴内脏肥胖个体每日食用核桃对内皮功能和其他心脏风险生物标志物的影响。
46 名超重成年人（平均年龄 57.4 岁；28 名女性，18 名男性）腰围升高，且有 1 种或多种其他代谢综合征迹象，被随机分配到两个 8 周的核桃丰富的随意饮食和无核桃的随意饮食序列中，其间有 4 周的洗脱期。主要观察指标是肱动脉血流介导的血管扩张（FMD）的变化。次要指标包括血清脂质谱、空腹血糖和胰岛素、稳态模型评估-胰岛素抵抗值、血压和人体测量指标。
与对照组饮食相比，当受试者食用富含核桃的饮食时，FMD 从基线显著改善（1.4%±2.4%比 0.3%±1.5%；p=0.019）。收缩压降低也呈现出有益的趋势，并且保持了基线人体测量值。其他指标没有变化。
每天摄入 56 克核桃可改善超重伴内脏肥胖成年人的内皮功能。在饮食中添加核桃不会导致体重增加。进一步研究核桃摄入在糖尿病和 CVD 预防中的潜在作用是必要的。
