Scientists have discovered why coffee seems to be good for the heart and said that caffeine intake equivalent to drinking four cups of coffee a day could lead to improved heart health.
Although previous research has linked coffee to lower risks for various diseases, including type 2 diabetes, stroke and heart disease, scientists did not quite understand exactly how these health benefits occur.
Now, scientists in Germany have found that consuming a daily amount of caffeine equivalent to drinking four cups of coffee helps protect cardiovascular cells in mice and improves the cells’ ability to recover from damage.
The new study, conducted by Heinrich-Heine-University and the IUF-Leibniz Research Institute for Environmental Medicine, was published in the journal PLOS Biology on Thursday.
In their experiment, the team focused on a protein called p27. They found that caffeine triggered the movement of p27 into mitochondria, the cell’s power generators, leading to a variety of beneficial changes in mice.
In addition to helping repair heart muscle and protecting heart muscle cells from dying after a heart attack, the mitochondrial p27 promoted migration of endothelial cells, which line the arteries and veins. The protein also caused cells called fibroblasts to convert into cells containing contractile fibres, a process which supports heart function.
The team found that caffeine protected against heart damage in unhealthy mice, including in pre-diabetic, obese mice and in elderly mice.
“Our results indicate a new mode of action for caffeine, one that promotes protection and repair of heart muscle through the action of mitochondrial p27,
said Professor Judith Haendeler, one of the study’s authors from Heinrich-Heine-University. “These results should lead to better strategies for protecting heart muscle from damage, including consideration of coffee consumption or caffeine as an additional dietary factor in the elderly population.”
The amount of caffeine needed to trigger the movement of p27 into the mice’s mitochondria equates to drinking four cups of coffee for humans, researchers said. According to Forbes, other research has also suggested four cups of coffee a day is optimal.
Experts not involved in the study welcomed the findings, but said more research is needed to investigate what implications the results might have for humans.
Commenting on the study, Tim Chico, a professor of cardiovascular medicine at the University of Sheffield in the UK, said: “These are very interesting findings but need to be confirmed in clinical trials before we can tell whether caffeine is truly helpful after a heart attack in humans.”
Chico added that people should not alter their coffee consumption just yet. “I do not think people need to drink more coffee in response to this study, but that people who already drink coffee can be reassured that it might have health benefits (as long as they don’t use it to wash down an enormous muffin, cake, or doughnut),” he said.
Dr Ian Johnson, a nutrition researcher at Quadram Institute Bioscience in the UK, called the new study “an impressive piece of laboratory work,” but cautioned that “it is important to be aware that this new work has made no direct observations on humans, and it doesn’t confirm that consumption of coffee at any level has overall health benefits.”