Dozens of dietary supplements are marketed for blood pressure control, but the evidence for effectiveness for most is not established. Chlorogenic acids are naturally occurring compounds which are abundant in unroasted coffee beans (green coffee). Laboratory studies have shown that chlorogenic acids can scavenge free radicals and increase antioxidant capacity, and researches in animals have also demonstrated that chlorogenic acids can cause blood vessel dilatation. Furthermore, consumption of chlorogenic acids in healthy humans has been shown to cause reductions in blood pressure by promoting the effects of nitric oxide (a potent vasodilator).
To evaluate the effect of chlorogenic acids on blood pressure, we evaluated the evidence from clinical trials evaluating the effect of chlorogenic acids. We searched five electronic databases and included only double-blinded randomised clinical trials (RCTs). We also assessed the quality of reporting of the included studies.
We identified seven eligible studies, out of which five with a total of 364 participants were included for analysis. The trials lasted between four and 26 weeks. There was some variation in the quality of reporting for the included RCTs. Meta-analysis showed that chlorogenic acid caused significant reductions in both systolic and diastolic blood pressures. All the studies reported chlorogenic acids as safe.
Consumption of chlorogenic acids could generate reductions in systolic and diastolic blood pressures. Few clinical trials examining the effects of chlorogenic acids have been published; they vary in design and quality of reporting. Clinical trials examining the effects of chlorogenic acids are confined to Asian populations, and have been largely funded by chlorogenic acid manufacturers. Independent trials evaluating the effects of chlorogenic acids in other populations should be a priority.
Onakpoya IJ, Spencer EA, Thompson MJ, Heneghan CJ. The effect of chlorogenic acid on blood pressure: a systematic review and meta-analysis of randomized clinical trials. http://www.ncbi.nlm.nih.gov/pubmed/24943289
Food consumer. 20th June, 2014. Breaking news: Green coffee bean extract may help high blood pressure.