DALLAS, Nov. 21 (UPI) -- The caffeine in a cup of coffee may help small blood vessels work better, but it isn't clear why, researchers in Japan say.
Study leader Dr. Masato Tsutsui, a cardiologist and professor in the pharmacology department at the University of the Ryukyus in Okinawa, Japan, said the study involved 27 healthy adults. Researchers said they found 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.