A study of 27 healthy adults showed — for the first time — that drinking a cup of caffeinated coffee significantly improved blood flow in a finger, which is a measure of how well the inner lining of the body’s smaller blood vessels work. Specifically, participants who drank a cup of caffeinated coffee had a 30 percent increase in blood flow over 75 minutes compared to those who drank decaffeinated coffee.
“This gives us a clue about how coffee may help improve cardiovascular health,” said Masato Tsutsui, M.D., Ph.D., lead researcher and a cardiologist and professor in the pharmacology department at the University of the Ryukyus in Okinawa, Japan.
The study adds to a growing body of research about coffee, the world’s most widely consumed beverage. Previous studies showed that drinking coffee is linked to lower risks of dying from heart disease and stroke, and that high doses of caffeine may improve the function of larger arteries.
Compared to decaf, caffeinated coffee slightly raised participants’ blood pressure and improved vessel inner lining function. Heart rate levels were the same between the two groups.
It’s still unclear how caffeine works to improve small blood vessel function, although Tsutsui suggested that caffeine may help open blood vessels and reduce inflammation.
“If we know how the positive effects of coffee work, it could lead to a new treatment strategy for cardiovascular disease in the future,” said Tsutsui.