New Delhi : Most adults can safely consume up to 400 mg of caffeine per day, equivalent to up to five 8-ounce cups of caffeinated coffee, without increasing cardiovascular risk, according to a new scientific statement released by the American Heart Association (AHA).
The review also suggests that moderate coffee consumption may be associated with a lower risk of several cardiovascular conditions, although researchers caution that individual responses to caffeine can vary.
Published in the peer-reviewed journal Circulation, the AHA scientific statement reviews the latest evidence on caffeine and cardiovascular disease.
It concludes that consuming up to 400 mg of caffeine daily, particularly through black caffeinated coffee without added sugars or cream, is generally safe for most adults and may be linked to a lower risk of heart disease, heart failure and stroke in some individuals.
“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 5 cups of caffeinated coffee per day without added sugars or fillers, is safe and does not increase cardiovascular risk,” said Gregory M Marcus, MD, MAS, FAHA, chair of the scientific statement writing group and professor of medicine at the University of California, San Francisco.
He added, “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.”
The statement notes that coffee remains the primary source of caffeine in most research studies, making it difficult to separate the effects of caffeine from other naturally occurring compounds in coffee. Researchers also pointed out that observational studies cannot establish cause and effect, while ingredients commonly added to coffee, such as sugar, flavoured syrups, milk and cream, may influence health outcomes.
According to the review, drinking two to four cups of caffeinated coffee per day has been linked to a lower risk of heart disease, heart failure and stroke. However, consuming more than four cups daily may increase the risk of heart failure in some people.
The report also highlights that black caffeinated coffee without additives has been associated with a lower risk of Type 2 diabetes, heart disease, stroke, heart failure and some irregular heart rhythms. At the same time, randomised clinical trials found that caffeine in coffee may reduce the risk of atrial fibrillation while increasing the likelihood of premature ventricular contractions (PVCs).
Researchers warned that not all caffeinated products have the same impact. Energy drinks and energy shots often contain significantly higher concentrations of caffeine, ranging from 40-69 mg per fluid ounce, compared with 9.4-20.6 mg per fluid ounce in regular brewed coffee. These products have been associated with increased blood pressure and abnormal heart rhythms.
The scientific statement also explains that caffeine affects people differently depending on genetics, metabolism, age, medications and habitual caffeine intake. Short-term effects may include temporary increases in blood pressure, heart rate, blood sugar and alertness, while some individuals may experience heart palpitations or sleep disruption.
Marcus emphasised that moderation and individual tolerance remain important.
“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. 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,” he said.
The American Heart Association added that more randomised controlled trials are needed to better understand how different sources of caffeine-including tea, soda, energy drinks and supplements–affect cardiovascular health and why responses vary among individuals.
