Drinking two or more cups of coffee a day may double the risk of death from cardiovascular disease among people with severe high hea (160/100 mm Hg or higher) compared to non-coffee drinkers, according to research published in the open-access, peer-reviewed Journal of the American Heart Association (JAHA). In contrast, one cup of coffee and daily green tea consumption did not increase the risk of death related to cardiovascular disease at any blood pressure measurement, even though both drinks contain caffeine, the study, conducted among more than 18,600 men and women in Japan, found. According to the United States Food and Drug Administration (FDA), an 8-ounce (about 240 ml) cup of green or black tea has 30-50 mg of caffeine, and an 8-ounce cup of coffee has closer to 80-100 mg. Previous research found that drinking one cup of coffee a day may help heart attack survivors by lowering their risk of death after a heart attack, and may prevent heart attacks or strokes in healthy individuals. Other studies have suggested that drinking coffee regularly may reduce the risk of developing chronic illnesses, such as Type 2 diabetes and some cancers; may help to control appetite; may help to lower the risk of depression or boost alertness, although it is not clear if this effect is from the caffeine or something else in coffee. On the harmful side, too much coffee may raise blood pressure and lead to anxiety, heart palpitations and difficulty sleeping. “Our study aimed to determine whether the known protective effect of coffee also applies to individuals with different degrees of hypertension; and also examined the effects of green tea in the same population,” the study’s senior author Hiroyasu Iso, professor emeritus at Osaka University, said. “To the best of our knowledge, this is the first study to find an association between drinking 2 or more cups of coffee daily and cardiovascular disease mortality among people with severe hypertension.” High blood pressure, also known as hypertension, occurs when the force of blood pushing against the walls of blood vessels is consistently too high, making the heart work harder to pump blood. Current blood pressure guidelines from the American Heart Association and the American College of Cardiology classifies hypertension as a blood pressure reading of 130/80 mm Hg or higher. American Heart Association
