November 21, 2013
Coffee Boosts Blood Flow, Regular And Decaf
Based on personal experience, you may already know that coffee stimulates blood flow, but a new study from a team of Japanese researchers has found that caffeine found in coffee may only be part of the story.
In a new study presented at the American Heart Association’s Scientific Sessions 2013 in Dallas this week, a cup of caffeinated coffee caused a 30 percent increase in blood flow over a 75-minute period. The study team noted that participants’ level of adrenaline were basically the same after drinking both regular and decaf coffee.
“This gives us a clue about how coffee may help improve cardiovascular health,” said Dr. Masato Tsutsui, a lead author of the study and a professor of pharmacology at the University of the Ryukyus in Okinawa, Japan.
For the study, the Japanese team recruited 27 adults between the ages of 22 and 30 who were not regular coffee drinkers. After participants drank a cup of caffeinated coffee, the researchers interrupted blood flow to their hand for one minute. Participants then had the blood flow in their fingers measured using non-invasive Doppler flowmetry, which involves determining how a laser beam is scattered by the movement of red blood cells as it passes underneath the skin. The entire process was repeated two days later with decaffeinated coffee.
In addition to finding that caffeinated coffee provided a boost to vascular function in the participants’ index finger, the research team also discovered that regular coffee slightly increased participants' blood pressure and lowered finger blood flow, compared with decaf coffee. The research team also pointed out that the heart rates for participants after drinking both types of coffee were essentially same.
The study was funded by the All Japan Coffee Association. Cardiologist Vincent Bufalino, a spokesman for the heart association told USA Today, "it's hard to come to broad-based scientific conclusions based on this one small study.”
“The research is limited to one cup of coffee,” he added.
Bufalino said further research should focus on the effects of drinking higher volumes of caffeine.
"Small amounts of coffee may have a benefit, but a higher consumption of coffee definitely raises blood pressure. It definitely raises heart rate, and it makes you more prone to heart palpitations," Bufalino said. "We see that every day in terms of the use of caffeine in patients. A lot of people sense that a cup of coffee gives them a lift but too much can have negative effects."
The Japanese study is being presented just three months after another study, published in the journal Hepatology, found increased caffeine consumption could reduce fatty liver in people with non-alcoholic fatty liver disease (NAFLD), a condition closely linked with diabetes. The only current treatments for NAFLD are diet and exercise.
Published in August, the study said caffeine-like drugs could be developed to provide the desired effect on the liver without the usual side effects linked to caffeine. They added that caffeine could have other unknown benefits that might be explored by future research.