Just when you think we’ve gotten to the bottom of this whole “coffee is good for you” thing, a new team of researchers fearlessly plumb the depths even further to find an as-yet-undiscovered cavern of coffee healthfulness. In a new study of nearly 350,000 participants, researchers from the Australian Centre for Precision Health found the number of cups of coffee you can drink per day before the risks outweigh the benefits. That number is five.
As reported by Inc.com, the new study first appeared in the March 2019 issue of the American Journal for Clinical Nutrition and was made public last week. In it, authors Ang Zhou and Elina Hyppönen were looking to discover if a specific genotype, CYP1A2, has any effect on “the association between habitual coffee consumption and the risk of cardiovascular disease (CVD).” For their work, the pair of researchers pored over data on 347,077 individuals in the UK Biobank—including 8,368 people with CVD—to cross-reference their genetic data against their “habitual coffee intake.”
Though their results found no link between the CYP1A2 genotype and an increased risk of CVD, Ang and Hyppönen's work did uncover some interesting correlations. Using those who drank one to two cups of coffee daily as the baseline, the results of the survey were “nonlinear.” They found that those who didn't drink coffee or only drank decaf were linked with an increase in CVD, by 11% and 7%, respectively. But those who drank six or more cups daily boosted the instances of CVD to 22%, double that of the non-coffee drinkers and triple of the decaf drinkers.
“In order to maintain a healthy heart and a healthy blood pressure, people must limit their coffees to fewer than six cups a day – based on our data six was the tipping point where caffeine started to negatively affect cardiovascular risk,” Hyppönen states.
Mark it five, dude. That's the limit science is putting on the number of cups of coffee you should have a day. For most people, five cups gives a pretty wide berth before running afoul of the scientific limits. For everyone else, though, I'd suggest maybe altering your coffee intake to just one cup daily. The key is finding the right cup.