A new American Heart Association scientific statement says up to 400 milligrams of caffeine per day — about five eight-ounce cups of coffee — is generally safe for most adults.
The review found that moderate black coffee consumption is linked with a lower risk of several cardiovascular conditions in some people.
Researchers caution that energy drinks and coffee loaded with sugar, syrups or cream don't appear to offer the same potential benefits.
For many people, the day doesn't officially begin until that first cup of coffee. While caffeine has long had a mixed reputation when it comes to heart health, a new scientific statement from the American Heart Association suggests there's reassuring news for most coffee drinkers.
After reviewing the latest research, experts concluded that consuming up to 400 milligrams of caffeine per day — roughly three to five eight-ounce cups of regular black coffee — is generally safe for most adults. In some people, that level of coffee consumption was also associated with a lower risk of several cardiovascular conditions, including heart disease, heart failure and stroke.
“Caffeine consumed in coffee is a key part of daily life for millions of people, and in our review of the most recent research, for most adults, intake of up to 400 mg of caffeine/day, the equivalent of up to five cups of caffeinated coffee per day without added sugars or fillers, is safe and does not increase cardiovascular risk,” researcher Gregory M. Marcus, M.D., M.A.S., FAHA, said in a news release.
“However, high doses of caffeine, such as those found in energy drinks including energy shots, may have harmful effects on the heart and should be avoided.”
What the researchers reviewed
Rather than conducting a new clinical trial, the American Heart Association assembled a panel of experts to evaluate the most current evidence on caffeine and cardiovascular disease.
The scientific statement summarizes findings from observational studies, randomized clinical trials, and other research examining how caffeine affects blood pressure, cholesterol, heart rhythm, diabetes risk, and overall cardiovascular health.
The researchers looked at caffeine from several sources, including coffee, tea, energy drinks and supplements.
They also considered how preparation methods and ingredients could influence health outcomes. For example, black coffee was evaluated separately from coffee drinks that contain added sugar, flavored syrups, or cream. The review also highlighted differences between naturally caffeinated beverages and highly concentrated sources of caffeine, such as energy shots.
What the findings mean for consumers
Overall, the evidence suggests that moderate consumption of plain, caffeinated coffee can fit into a heart-healthy lifestyle for many adults.
The review found that drinking black coffee without added sugars or cream was associated with a lower risk of conditions such as type 2 diabetes, coronary heart disease, stroke, heart failure, and some abnormal heart rhythms. However, the authors stressed that these studies show associations rather than proving that coffee directly causes these health benefits.
The statement also points to some important caveats. High amounts of caffeine — particularly from energy drinks and energy shots — were linked to increased risks of high blood pressure and abnormal heart rhythms.
Researchers also noted that adding sugar, flavored syrups and cream to coffee may reduce any potential health benefits. Finally, because people process caffeine differently, what's appropriate for one person may not be right for another. More research is still needed to better understand how different caffeine sources affect different individuals.
“Although research suggests that caffeine consumption may be associated with certain cardiovascular benefits for some people, it’s important to remember that there is no ‘one-size-fits-all’ strategy for safe caffeine consumption,” said Dr. Marcus.
“People can respond very differently to caffeine based on various factors, such as age, medications, underlying health conditions, genetics, and how quickly their bodies metabolize it. What may be a reasonable amount for one person could cause unwanted effects, such as heart palpitations, anxiety, or sleep disruption, in another. That’s why it’s important to pay attention to how your body responds to caffeine and talk with your healthcare team about what is right for you.”