Despite its widespread use, the impact drinking coffee can have on the human body is still being studied intensively by the medical community. In the 1500s, doctors believed that coffee consumption could lead to an increased desire for sex. And in the centuries since, coffee use has been blamed for everything from impotence to blindness. And even in the past several decades, some studies had seemed to show that coffee consumption had a negative impact on the circulatory system and blood pressure.
Part of the challenge of studying the effects of coffee consumption has always been that the typical cup of coffee contains more than 1,000 distinct compounds and its not clear what their long-term impact might be on the average coffee drinker. Many of the physical changes might be slow-acting and only seen on patients who are followed for several decades. That’s especially been a challenge for scientists in recent years, given the average American’s tendency to move to a new location at least once or twice during their working lives.
The American Heart Association’s Journal Circulation has come up with a solution to that problem by aggregating the results from several long-term studies that followed patients for up to 30 years. By combining the data, it provided the authors with a wider range of data points and the opportunity to spot more subtle trends than would be possible using a smaller group of patients.
The article studied data collected from more than 235,000 patients who were asked to fill out a health questionnaire every four years. And the results seem to point to coffee having a positive net impact on patients, when consumer in moderation. The article revealed that participants who drank less than five cups of coffee per day experienced lower rates of suicide, Type 2 diabetes, Parkinson’s disease and cardiovascular and neurological illnesses. But the results weren’t able to draw any conclusions about why these effects took place.
But before anyone decides to take up coffee drinking in order to improve their health, it should be noted that previous studies have also shown mixed results on the positive impacts of coffee. There also seems to be a genetic component at play, with some coffee drinkers seeming to be genetically predisposed to the positive influences of coffee.
One thing that this American Heart Association study does have in common with earlier studies is that a higher consumption of coffee daily both negates the positive effects as well as negatively impacts the health of the patients. While there isn’t a consensus on what qualifies as “too much” coffee consumption, keeping it below five cups a day seems to be a good idea.