That morning cup o' joe or mid-afternoon coffee pick-me-up may play a role in keeping your heart healthy, depending on how much you drink.
A meta-analysis of five previously completed prospective studies finds that drinking two 8-ounce cups of coffee a day gives people an 11% lower risk of developing heart failure, compared to people who don't consume any coffee.
The analysis, published in the American Heart Association's journal Circulation: Heart Failure, reviewed five studies conducted between 2001 and 2011 and included a total of 140,220 patients.
"Heart failure shares risk factors with other cardiovascular diseases and high blood pressure and Type 2 diabetes are particularly strong risk factors for heart failure," explains Elizabeth Mostofsky, the first author of the analysis and a post doctoral research fellow at the Cardiovascular Epidemiology Research Unit at Beth Israel Deaconess Medical Center.
"We think coffee is lowering the risk for diabetes which is lowering the risk for heart failure."
But don't reach for the coffee pot just yet. Drinking two cups of coffee may help prevent heart failure but Mostofsky and her colleagues found that drinking more than four cups a day seems to undermine the protective quality.
"Protection slowly decreases with more consumption and it seems there's no further benefit for people who drink five or more servings a day and there may actually be potential for harm," says Mostofsky.
The studies that made up the analysis did not take into account if participants drank caffeinated or decaffeinated coffee. However, Mostofsky notes that the studies were conducted in Finland and Sweden, two countries where caffeinated coffee is typically consumed. The studies also did not look at how the coffee was brewed, how strong it was, or what time of day the participants drank it.
Still, the analysis jibes with previous research that shows two cups of coffee may be good for you. Last month, the New England Journal of Medicine published a study that found drinking at least two cups of coffee was linked to a longer life.
For its part, the American Heart Associated recommends that patients with heart failure limit their intake to no more two 8-ounce cups of coffee or any other caffeinated beverage, a day.