How does coffee affect blood pressure and endothelial function in adults with hypertension? Original paper

In this randomized crossover study, caffeinated and decaffeinated coffee (compared to water) did not affect blood pressure or endothelial function in participants with high blood pressure.

The acute effects of coffee consumption on blood pressure and endothelial function in adults with hypertension.

14 adults (ages 40–65; 7 men and 7 women) who were recruited from 2 outpatient clinics in Brazil.

All of the participants were taking antihypertensive medications to manage their blood pressure, and all of them were habitual coffee consumers.

In this randomized crossover study, the participants completed 3 different conditions: they consumed caffeinated coffee (135 mg of caffeine and 61 mg of chlorogenic acids), decaffeinated coffee (5 mg of caffeine and 68 mg of chlorogenic acids), or water.

Blood pressure was measured before each beverage was consumed and every 10 minutes afterward for 90 minutes. Endothelial function and microvascular reactivity were assessed before and 90 minutes after beverage consumption using peripheral arterial tonometry (PAT) and skin blood flow, respectively.

There were no differences in blood pressure, endothelial function, or microvascular reactivity when comparing the coffee, decaffeinated coffee, and water conditions.

Compared to baseline, systolic blood pressure increased after coffee (+10 mmHg) and decaffeinated coffee (+8 mmHg). Furthermore, endothelial function worsened after caffeinated and decaffeinated coffee compared to baseline.

We don’t know much about the participants’ habitual caffeine consumption. Though it was reported that they consumed an average of 376 mL of coffee per day, it’s hard to estimate what their total caffeine intake would be, given that the caffeine content of coffee varies widely. Based on the average caffeine content of the beverages used in the study, the average daily caffeine intake of the participants is estimated as approximately 270 to 300 mg per day.