A major new review by the American Heart Association has put a figure on how much caffeine most adults can consume without raising their cardiovascular risk: 400 mg a day. The analysis also found that the lowest risk of death was among people drinking between two and four cups daily.
The recommended limit
Coffee is the world's most popular source of caffeine and has been associated with a range of health benefits, but the question of how much is safe has remained open.
According to the review, consuming up to 400 mg of caffeine a day, roughly equivalent to five cups of coffee, is generally safe for most adults and may be linked to better heart health.
"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," said Gregory M. Marcus, co-author of the paper and professor of medicine at the University of California, San Francisco.
Links to lower cardiovascular risk
The analysis found that this level of intake appeared to be associated with a lower risk of several cardiovascular conditions, including heart failure, heart disease and stroke. In some individuals, it was also linked to a lower risk of hypertension and type 2 diabetes.
Other sources of caffeine
While coffee is the main source of caffeine for most adults, daily intake also comes from tea, chocolate, fizzy drinks and both over-the-counter and prescription medications.
The authors note that much less is known about caffeine from these sources, particularly at high doses. Energy drinkswere highlighted as a possible cause of cardiovascular harm that requires further study.
How the body processes caffeine
Caffeine from coffee is metabolised by the liver and, for most people, reaches its peak concentration within an hour.
The way each person processes it depends on genetics, metabolism, age and previous intake. Regular coffee drinkers may build up a tolerance to higher levels of caffeine, while others may feel stronger effects from the same amount.
No single safe level for everyone
Marcus stressed that the findings do not apply equally to all.
"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," he said.
"What may be a reasonable amount for one person could cause unwanted effects, such as heart palpitations, anxiety or sleep disruption, in another," he added, noting that it is important to pay attention to how each body responds to caffeine.
Added sugar and syrups
The researchers also pointed out that not all ways of drinking coffee are equally beneficial for the heart. Large amounts of added sugar, flavoured syrups and dairy products can significantly increase calorie intake and may cancel out the potential benefits of coffee itself.
