Drinking 25 cups of coffee might make you a jittery mess but it's safe, says science

ByNatalia Lusinski

If you’re a Starbucks addict who worries about the impact drinking coffee has on your heart, rest easy and get that refill. CNN reported on June 3 that new research found that drinking several cups of coffee a day — even up to 25 — is actually no worse for the arteries than drinking less than one cup each day.

For the study, which was partly funded by the British Heart Foundation (BHF), scientists divided 8,412 British people into three groups based on their reported average coffee consumption. One group contained people who drank less than one cup of coffee a day; another had people who drank between one and three cups; and the last featured those who drank more than three cups daily, with some drinking up to 25 cups per day (people who had more than 25 cups a day — yes, they exist — were excluded from the study).

To assess how drinking coffee affected heart health, participants were given MRI heart scans and infrared pulse wave tests; researchers also took into account each person's age, gender, ethnicity, smoking status, height, weight, alcohol use, eating habits, and blood pressure. Despite all the individual differences, though, the study found that for all the people involved, drinking coffee didn't actually increase their arterial stiffness, as past studies have suggested would happen.

“The main message for people to take away from this is that coffee can be enjoyed as part of a healthy lifestyle, and coffee lovers can be reassured by this result in terms of blood vessel stiffness outcomes,” Kenneth Fung, who led the data analysis at Queen Mary University of London, told CNN.


According to the American Heart Association, good arterial health can help prevent a heart attack or stroke; coronary arteries supply the heart muscle with blood flow that brings oxygen to the heart muscle, and when that flow is severely reduced or cut off completely, that's when a heart attack occurs. Yet while coffee might not affect arterial health, other things can that the BHF study didn't take into account, notes Dr. Bryant Nguyen, a cardiologist affiliated with Sharp Grossmont Hospital. "Arterial stiffness is also age-related, so the study may not catch an effect of coffee on the rate of artery stiffening as participants age,” he explains.

Still, Dr. Nguyen adds, "any effect of coffee on arterial health is most likely going to be very small.” Of course, just because major coffee consumption might not hurt your arteries doesn't mean that drinking two dozen cups a day is healthy. “It is essential to note that the study’s median amount of coffee consumed by its subjects was around five cups a day; this means that 25 cups of coffee is not a recommended amount," Dr. Niket Sonpal, an NYC internist and gastroenterologist, tells Mic.

Caffeine, he notes, can cause sleep deprivation, anxiety, the jitters, headaches, and an upset stomach, not to mention addiction in regular users. “If you are using coffee as a means for energy and alertness — but have strong reactions to caffeine or feel anxious when it is in your system — this could be a cause to cut back on caffeine as a strategy for productivity at work or school,” Dr. Sonpal adds. He also says to keep in mind that the BHF study found that moderate and heavy coffee drinkers were most likely to smoke and consume alcohol regularly, and those behaviors can, of course, have serious consequences on your well-being.

Still, the study's findings are good news if heart health is your main priority. “There are several conflicting studies saying different things about coffee, and it can be difficult to filter what we should believe and what we shouldn’t,” Professor Metin Avkiran, BHF’s associate medical director, said with the report. “This research will hopefully put some of the media reports in perspective, as it rules out one of the potential detrimental effects of coffee on our arteries.”