Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia, Australia.
Nestlé Research Lausanne, Lausanne, Switzerland.
Am J Clin Nutr. 2021 Feb 2;113(2):370-379. doi: 10.1093/ajcn/nqaa312.
Epidemiological studies have reported lower risk of cardiovascular disease with moderate coffee consumption. In addition, emerging evidence indicates that consumption of coffee beverages enriched in chlorogenic acids (CGAs) may influence blood pressure and endothelial function, suggesting that the beneficial cardiovascular effect of coffee may relate to its CGA content.
We conducted a double-blind randomized crossover trial to test the effect of acute consumption of a decaffeinated green coffee extract (DGCE), rich in CGAs, on endothelial function in healthy subjects.
We compared 3 different doses of DGCE (302, 604, and 906 mg, respectively) with a placebo. Endothelial function was defined as the percentage change in the internal diameter of the brachial artery in response to flow-mediated dilation (%FMD). In addition, we followed the plasma concentration-time profiles of 25 systemic CGA metabolites over 24 h after DGCE consumption and we explored the relation between systemic concentrations of CGAs and the effect on %FMD.
The DGCE formulations containing different amounts of CGAs resulted in dose-proportional increases in overall total polyphenol concentrations. The systemic appearance of total CGAs was biphasic, in agreement with previous results suggesting 2 sites of absorption in the gastrointestinal tract. Compared with the placebo group, a significant FMD increase (>1%) was observed 8.5, 10, and 24 h after consumption of 302 mg DGCE (∼156.4 mg CGAs). The differences with placebo observed in the other 2 groups were not statistically significant. Evaluation of the relation between phenolic exposure and %FMD showed a positive tendency toward a larger effect at higher concentrations and different behavior of CGA metabolites depending on the conjugated chemical position.
We demonstrated an acute improvement in %FMD over time after ingestion of a DGCE, explained at least partly by the presence in the blood circulation of CGAs and their metabolites. This trial was registered at clinicaltrials.gov as NCT03520452.
流行病学研究报告称，适量饮用咖啡可降低心血管疾病风险。此外，新出现的证据表明，饮用富含绿原酸（CGAs）的咖啡饮料可能会影响血压和内皮功能，这表明咖啡的有益心血管作用可能与其 CGAs 含量有关。
我们进行了一项双盲随机交叉试验，以测试急性摄入富含 CGAs 的脱咖啡因绿原咖啡提取物（DGCE）对健康受试者内皮功能的影响。
我们比较了 3 种不同剂量的 DGCE（分别为 302、604 和 906 mg）与安慰剂。内皮功能定义为肱动脉内径对血流介导扩张的百分比变化（%FMD）。此外，我们还在 DGCE 摄入后 24 小时内跟踪了 25 种全身 CGAs 代谢物的血浆浓度-时间曲线，并探讨了 CGAs 系统浓度与对 %FMD 的影响之间的关系。
含有不同 CGAs 量的 DGCE 配方导致总多酚浓度呈剂量依赖性增加。全身 CGAs 的出现呈双相，与先前表明胃肠道内有 2 个吸收部位的结果一致。与安慰剂组相比，摄入 302 mg DGCE 后 8.5、10 和 24 小时，FMD 显著增加（>1%）（约 156.4 mg CGAs）。其他 2 组与安慰剂组相比，差异无统计学意义。对酚类暴露与 %FMD 之间的关系进行评估表明，随着浓度的升高，作用更大，且 CGAs 代谢物的行为取决于共轭化学位置的不同。
我们证明了在摄入 DGCE 后，%FMD 随着时间的推移而急性改善，这至少部分归因于血液循环中 CGAs 及其代谢物的存在。本试验在 clinicaltrials.gov 上注册为 NCT03520452。
