- A new study has found that drinking three or more cups of coffee is linked to lower blood pressure.
- People are generally advised not to drink too much coffee because caffeine can raise blood pressure.
- However, coffee also contains certain compounds which can lower blood pressure.
- This study provides evidence that moderate coffee consumption could be safe for those with hypertension.
A new study published in the journal Nutrients reports that drinking three or more cups of coffee daily was associated with lower peripheral and central blood pressure.
According to the study’s lead author, Dr. Arrigo FG Cicero, associate professor in the Department of Medical and Surgical Sciences at the University of Bologna, peripheral and central blood pressure are markers of arterial stiffening and aging.
In older adults with high blood pressure, the large arteries tend to become stiffer, leading to higher systolic blood pressure (the top number of the blood pressure reading) and wider pulse pressure (the difference between the top and bottom numbers).
The authors note in their report that the effects of coffee on blood pressure are still under debate, primarily because it is known that the caffeine content of coffee can raise blood pressure in the short term.
However, these effects may be ameliorated by the antioxidants found in coffee which can help dilate blood vessels as well as protect cells against free radicals.
Cicero and his team wanted to investigate just how the interaction between caffeine and other compounds found in coffee would influence the incidence of blood pressure.
To conduct their study, Cicero’s team examined a sample including 720 men and 783 women who were participants in the Brisighella Heart Study.
This ongoing study, which first began in 1972, includes a randomized sample representative of a rural Northern Italy town called Brisighella.
The researchers looked at participants’ blood pressure and coffee-drinking habits, as well as a selection of other data relevant to cardiovascular health.
Upon analysis of the data, they found that coffee consumption was associated with lower blood pressure.
“The trend seems to be positive from 2 [cups of] coffee per day,” said Cicero. “So, coffee drinking should not be a priori prohibited in current coffee drinkers, if the fear is that coffee could increase BP levels.”
Megan K. Rhoads, PhD and postdoctoral scholar, Department of Medicine, Division of Nephrology at The University of Alabama at Birmingham, said there are several mechanisms through which coffee consumption could lower blood pressure, some of which have been demonstrated in animal studies.
“Coffee contains caffeine, which can both raise and lower blood pressure in acute settings, but it also contains antioxidants and bioactive compounds which may be responsible for the blood pressure lowering effect,” she explained.
Rhoads offered chlorogenic acid as an example of a compound that can lower systolic blood pressure in rats.
“When processed by the gut microbiota, chlorogenic acid is broken down into metabolites that can increase nitric oxide bioavailability and lower blood pressure.”
Dr. Debabrata Mukherjee, chairman of the Department of Internal Medicine and professor of internal medicine at Texas Tech University Health Sciences Center El Paso, further explained: “Even though caffeine could increase BP levels (especially in individuals who usually do not drink coffee), the amount of other bioactive compounds in coffee counterbalance this effect with a final neutral-to-positive effect on BP.”
Chlorogenic acid, which is present in the highest concentration in coffee beans, is believed to be one of the main compounds in coffee that lowers blood pressure, according to Mukherjee. Quercetin may also play a role.
Dr. Jim Liu, a cardiologist at The Ohio State University Wexner Medical Center, said that while this study is small and focuses on a specific population, its findings are consistent with prior knowledge about how coffee affects blood pressure.
“Coffee can increase blood pressure acutely after consumption, but there really has not been any consistent evidence to show that moderate amounts of coffee consumption lead to long-term issues with high blood pressure or heart disease in general,” he noted.
“For patients with hypertension who consume moderate amounts of coffee, this study provides some more reassuring data that it’s OK to continue drinking moderate amounts of coffee and that it won’t negatively impact blood pressure. If anything, moderate coffee consumption may help with blood pressure,” said Liu.
Mukherjee added that moderate consumption would be equal to about four or five cups of coffee, although it’s not advised for people with existing severe hypertension.