For coffee drinkers worried about any potential health risks from the caffeine in their brew, a scientific review offers encouraging news.
A new scientific statement published this week by the American Heart Association shows that drinking up to 5 cups of caffeinated coffee a day (or about 400 milligrams of caffeine) is not only safe, but may also provide cardiovascular benefits.
Drinking caffeinated coffee without added sugars, flavors, or cream was linked to a lower risk of heart failure, heart disease, stroke, and type 2 diabetes.
“When it comes to consuming caffeine, one size does not fit all — individuals metabolize caffeine at very different rates,” says lead statement author Greg Marcus, MD, a specialist in the treatment of arrhythmias and the associate chief of cardiology for research at the University of California, San Francisco Health.
“But for people who enjoy coffee and have not noticed any problems from the caffeine, this review should be reassuring as it shows moderate coffee consumption might even be beneficial from a cardiovascular standpoint.”
In the review, Dr. Marcus and researchers also cautioned that drinking more than 400 milligrams of caffeine (like what you might get from energy drinks) may increase the risk of developing high blood pressure and irregular heart rhythm (arrhythmia).
Positives of Coffee Outweigh the Negatives
In the past, there was a concern that coffee might be harmful because caffeine can temporarily raise blood pressure and increase heart rate, says Alan Rozanski, MD, director of nuclear cardiology at Mount Sinai St. Lukes in New York City. “Large prospective studies and several randomized trials have largely overturned those earlier concerns.”
“The overall pattern is remarkably consistent: People who drink coffee regularly tend to have better cardiovascular outcomes than nondrinkers, with the greatest benefit generally occurring at moderate levels of consumption,” Dr. Rozanski says.
This latest paper showed several heart health benefits of coffee and caffeine drinking, including:
- Lower Heart Disease and Stroke Risk Drinking 2 to 4 cups of caffeinated coffee per day was linked to a lower risk of heart disease, heart failure, and stroke. However, drinking more than 4 cups of caffeinated coffee a day may increase the risk of heart failure.
- No Effect on Heart Rhythm Self-reported information from study participants suggests that drinking 1 to 3 cups of caffeinated coffee per day did not increase the risk of atrial fibrillation, or abnormal heart rhythm.
The statement notes that the long-term effects of regular caffeine consumption on blood pressure remain unclear and are likely minimal, though the risk may increase with high intake. However, energy drinks containing high levels of caffeine have been shown to significantly raise both systolic and diastolic blood pressure in healthy adults.
Why Might Coffee Be Good for You?
According to the review, many of the health benefits from coffee appear to come from the whole beverage, not just the caffeine. Marcus believes that while caffeine can briefly spike blood pressure, this may be offset by regular intake.
One way it benefits the heart is that it helps regulate sodium levels in the body. “Coffee drinkers may see their blood pressure go down because of its diuretic effect,” meaning it helps remove salt through the urine, says Marcus.
Sodium causes the body to hold extra water. This increases the amount of fluid and pressure within blood vessels, making the heart work harder.
Coffee also contains hundreds of compounds (such as polyphenols, chlorogenic acids, diterpenes, and trigonelline) that reduce oxidative stress. Cell damage from oxidative stress is a large part of what drives atherosclerosis, the narrowing and hardening of the arteries due to plaque buildup, says John P. Higgins, MD, a sports cardiologist with McGovern Medical School at the University of Texas Health Science Center in Houston.
“These bioactive compounds may lower inflammation and improve vascular health,” says Dr. Higgins, who was not involved in this investigation.
Finally, the caffeine in coffee may also motivate some people to get up and get moving, and more exercise can improve heart health. Marcus points to research showing that consuming coffee was associated with more than 1,000 additional steps per day.
Limitations of the Review
The authors of this report note that most studies on caffeine are observational, meaning they can show that drinking coffee and health benefits occur together, but they can’t prove that coffee truly causes these benefits.
Also, many studies do not account for the role of other ingredients commonly added to coffee, such as milk, cream, flavored syrups, or sugar.
Overall, this research explains what’s currently known about the benefits of drinking coffee and identifies areas that need further research. The authors do not make treatment recommendations.
Marcus adds that some studies have suggested that information on decaffeinated coffee is limited. Some research suggests that decaf may provide some heart benefits as well, although its effects are less known, as “the great majority of research, especially in large populations, focuses on caffeinated coffee.”
Expert Dos and Don’ts
Based on evidence so far, our health experts offer the following advice about drinking coffee and caffeine:
Coffee Dos
- Enjoy coffee in moderation as part of an overall healthy lifestyle, says Rozanski.
- Minimize adding sugar, flavored syrups, and heavy creamers. “These can turn coffee into a calorie-dense dessert,” says Higgins.
- Drink filtered coffee. Unfiltered coffee (French press, espresso, or Turkish coffee) contains compounds called diterpenes, which may raise cholesterol levels, Marcus says.
- Pay attention to your body’s response. 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.
Coffee Don’ts
- Don’t drink coffee to a level where you experience anxiety, heart palpitations, or difficulty sleeping, says Rozanski.
- Coffee cannot replace a good night’s rest. Don’t lean on coffee to mask chronic sleep deprivation. “Poor sleep itself raises cardiovascular risk. Avoid late-day intake if it disrupts sleep,” says Higgins.
- Don’t consume energy drinks. Energy drinks or shots can contain 3 to 4 times more caffeine than regular caffeinated coffee, according to the statement.
Energy drinks, bars, gels, and caffeine-based supplements often contain additional ingredients that may increase caffeine absorption, accelerate its effects, raise blood pressure, and increase the risk of cardiovascular harm.
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