The American Heart Association (AHA) has concluded a multi-tiered, multi-generational metastudy on the effects of black coffee, and the results are overwhelmingly positive for how a cup of coffee a day can keep the cardiologist at bay. 

The AHA study used the Precision Medicine Platform to compare dietary data among over 21,000 American adults to conclude that one to three cups of coffee can limit an individual’s risk to heart failure by anywhere from 5-12% per cup.

This is the link to the consumer version of the article by CNN.

This is the link to the more scientific version from the American Heart Association. 

*It should be noted, that the benefits of coffee are severely decreased when sugar and milk (or creamer) is used as an additive, and that the study was using 8oz. as the standard to measure a single cup of coffee.