Boon Evan A J, Croft Kevin D, Shinde Sujata, Hodgson Jonathan M, Ward Natalie C
Schools of Medicine and Biomedical Science, University of Western Australia, Perth, Western Australia.
Food Funct. 2017 Sep 20;8(9):3366-3373. doi: 10.1039/c7fo00926g.
A diet rich in plant polyphenols has been suggested to reduce the incidence of cardiovascular disease and type 2 diabetes mellitus, in part, via improvements in endothelial function. Coffee is a rich source of phenolic compounds including the phenolic acid, chlorogenic acid (CGA). The aim of the study was to investigate the effect of coffee as a whole beverage on endothelial function, blood pressure and blood glucose concentration. Twelve healthy men and women were recruited to a randomised, placebo-controlled, cross-over study, with three treatments tested: (i) 18 g of ground caffeinated coffee containing 300 mg CGA in 200 mL of hot water, (ii) 18 g of decaffeinated coffee containing 287 mg CGA in 200 mL of hot water, and (iii) 200 mL of hot water (control). Treatment beverages were consumed twice, two hours apart, with the second beverage consumed simultaneously with a 75 g glucose load. Blood pressure was recorded and the finger prick glucose test was performed at time = 0 and then every 30 minutes up to 2 hours. Endothelial function, assessed using flow-mediated dilatation (FMD) of the brachial artery, was measured at 1 hour and a blood sample taken at 2 hours to measure plasma nitrate/nitrite and 5-CGA concentrations. The FMD response was significantly higher in the caffeinated coffee group compared to both decaffeinated coffee and water groups (P < 0.001). There was no significant difference in the FMD response between decaffeinated coffee and water. Blood glucose concentrations and blood pressure were not different between the three treatment groups. In conclusion, the consumption of caffeinated coffee resulted in a significant improvement in endothelial function, but there was no evidence for benefit regarding glucose metabolism or blood pressure. Although the mechanism has yet to be elucidated the results suggest that coffee as a whole beverage may improve endothelial function, or that caffeine is the component of coffee responsible for improving FMD.
有人提出，富含植物多酚的饮食可部分通过改善内皮功能来降低心血管疾病和2型糖尿病的发病率。咖啡是酚类化合物的丰富来源，包括酚酸、绿原酸（CGA）。本研究的目的是调查作为一种完整饮品的咖啡对内皮功能、血压和血糖浓度的影响。招募了12名健康男性和女性参与一项随机、安慰剂对照、交叉研究，测试了三种处理：（i）18克研磨的含咖啡因咖啡，其中含有300毫克CGA，溶于200毫升热水中；（ii）18克脱咖啡因咖啡，其中含有287毫克CGA，溶于200毫升热水中；（iii）200毫升热水（对照）。处理饮品分两次饮用，间隔两小时，第二次饮品与75克葡萄糖负荷同时饮用。在时间=0时记录血压，并进行手指刺血葡萄糖测试，然后每30分钟记录一次，直至2小时。在1小时时测量使用肱动脉血流介导的扩张（FMD）评估的内皮功能，并在2小时时采集血样以测量血浆硝酸盐/亚硝酸盐和5-CGA浓度。与脱咖啡因咖啡组和水组相比，含咖啡因咖啡组的FMD反应显著更高（P<0.001）。脱咖啡因咖啡组和水组之间的FMD反应没有显著差异。三个处理组之间的血糖浓度和血压没有差异。总之，饮用含咖啡因咖啡可显著改善内皮功能，但没有证据表明对葡萄糖代谢或血压有益。尽管机制尚未阐明，但结果表明，作为一种完整饮品的咖啡可能会改善内皮功能，或者咖啡因是咖啡中负责改善FMD的成分。
