Food Components and Health Laboratory, Beltsville Human Nutrition Research Center, US Department of Agriculture, Agricultural Research Service, Beltsville, MD, USA.
Eur J Clin Nutr. 2012 Oct;66(10):1153-9. doi: 10.1038/ejcn.2012.101. Epub 2012 Aug 1.
BACKGROUND/OBJECTIVES: Flavanols may provide protection against insulin resistance, but little is known about the amounts and types of flavanols that may be efficacious.
SUBJECTS/METHODS: This study was designed to determine whether cocoa flavanols, over a range of intakes, improve biomarkers of glucose regulation, inflammation and hemostasis in obese adults at risk for insulin resistance. As an adjunct, green tea and cocoa flavanols were compared for their ability to modulate these biomarkers. In a randomized crossover design, 20 adults consumed a controlled diet for 5 days along with four cocoa beverages containing 30-900 mg flavanol per day, or tea matched to a cocoa beverage for monomeric flavanol content.
Cocoa beverages produced no significant changes in glucose, insulin, total area under the concentration-time curve (AUC) for glucose or total insulin AUC. As the dose of cocoa flavanols increased, total 8-isoprostane concentrations were lowered (linear contrast, P=0.02), as were C-reactive protein (CRP) concentrations (linear contrast, P=0.01). The relationship between cocoa flavanol levels and interleukin-6 (IL-6) concentrations was quadratic, suggesting that a maximum effective dose was achieved (quadratic contrast, P=0.01). There were no significant effects on measured indices of glucose regulation, nor on those of total 8-isoprostane, CRP and IL-6 concentrations, when cocoa and green tea were compared. However, relative to cocoa, green tea lowered fibrinogen concentrations (P=0.0003).
Short-term intake of cocoa and green tea flavanols does not appear to improve glucose metabolism; they do affect selected markers of one or more measures of oxidative stress, inflammation or hemostasis in obese adults at risk for insulin resistance.
背景/目的：黄烷醇可能有助于预防胰岛素抵抗，但人们对可能有效的黄烷醇的摄入量和种类知之甚少。
受试者/方法：本研究旨在确定在肥胖且有胰岛素抵抗风险的成年人中，黄烷醇的摄入量在一定范围内是否能改善葡萄糖调节、炎症和止血的生物标志物。作为辅助手段，比较了绿茶和可可黄烷醇对这些生物标志物的调节作用。采用随机交叉设计，20 名成年人在 5 天内摄入控制饮食，同时饮用 4 种含有 30-900mg 黄烷醇的可可饮料，或与可可饮料的单体黄烷醇含量相匹配的茶。
可可饮料对葡萄糖、胰岛素、葡萄糖总浓度-时间曲线下面积（AUC）和总胰岛素 AUC 没有显著影响。随着可可黄烷醇剂量的增加，总 8-异前列腺素浓度降低（线性对比，P=0.02），C 反应蛋白（CRP）浓度也降低（线性对比，P=0.01）。可可黄烷醇水平与白细胞介素-6（IL-6）浓度之间的关系呈二次曲线，表明达到了最大有效剂量（二次对比，P=0.01）。当比较可可和绿茶时，对葡萄糖调节的测量指标以及总 8-异前列腺素、CRP 和 IL-6 浓度均无显著影响。然而，与可可相比，绿茶降低了纤维蛋白原浓度（P=0.0003）。
短期摄入可可和绿茶黄烷醇似乎不能改善葡萄糖代谢；它们确实会影响肥胖且有胰岛素抵抗风险的成年人中一种或多种氧化应激、炎症或止血标志物。
