Acute Effects of Coffee Consumption on Blood Pressure and Endothelial Function in Individuals with Hypertension on Antihypertensive Drug Treatment: A Randomized Crossover Trial.

INTRODUCTION: Coffee is a complex brew that contains several bioactive compounds and some of them can influence blood pressure (BP) and endothelial function (EF), such as caffeine and chlorogenic acids (CGAs). AIM: This study aimed to evaluate the acute effects of coffee on BP and EF in individuals with hypertension on drug treatment who were habitual coffee consumers. METHODS: This randomized crossover trial assigned 16 adults with hypertension to receive three test beverages one week apart: caffeinated coffee (CC; 135 mg caffeine, 61 mg CGAs), decaffeinated coffee (DC; 5 mg caffeine, 68 mg CGAs), and water. BP was continuously evaluated from 15 min before to 90 min after test beverages by digital photoplethysmography. Reactive hyperemia index (RHI) assessed by peripheral arterial tonometry evaluated EF before and at 90 min after test beverages. At the same time points, microvascular reactivity was assessed by laser speckle contrast imaging. Repeated-measures-ANOVA evaluated the effect of time, the effect of beverage, and the interaction between time and beverage (treatment effect). RESULTS: Although the intake of CC produced a significant increase in BP and a significant decrease in RHI, these changes were also observed after the intake of DC and were not significantly different from the modifications observed after the consumption of DC and water. Microvascular reactivity did not present significant changes after the 3 beverages. CONCLUSION: CC in comparison with DC and water neither promoted an acute increase in BP nor produced an improvement or deleterious effect on EF in individuals with hypertension on drug treatment who were coffee consumers.

Effects of Oral Magnesium Supplementation on Vascular Function: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

INTRODUCTION: The effects of magnesium (Mg) supplementation on vascular function have been evaluated in some randomized controlled trials (RCT) but their results are conflicting. AIM: A systematic review and meta-analysis were conducted to summarize the effects of oral Mg supplementation on vascular function in RCT. METHODS: The databases MEDLINE (PubMed), Embase, Web of Science and Cochrane Library were accessed from inception to May 27, 2019. Intergroup differences (treatment vs. control group) related to changes in flow-mediated dilation (FMD) and pulse wave velocity (PWV), expressed as mean and standard deviation, were used to evaluate the effect of Mg supplementation on these outcomes. The results of the meta-analysis were expressed using a random-effects model. The heterogeneity between studies was evaluated using the I2 statistic. RESULTS: The oral supplementation of Mg had no significant effect on FMD (mean difference 2.13; 95% CI - 0.56, 4.82; p = 0.12) and PWV (mean difference - 0.54, 95% CI - 1.45, 0.36, p = 0.24). Heterogeneity for both outcomes (FMD and PWV) was high (I2 = 99%, p < 0.001). However, in subgroup analyses, oral Mg significantly improved FMD in studies longer than 6 months, in unhealthy subjects, in individuals older than 50 years, or in those with body mass index (BMI) ≥ 25 kg/m2. The reduced number of RCT and the heterogeneity among them were the main limitations. CONCLUSIONS: This meta-analysis suggest that oral Mg supplementation may improve endothelial function when conducted at least for 6 months and in unhealthy, overweight or older individuals. Registration number: PROSPERO CRD42019111462.