A new study from a team of scientists in Germany has revealed a previously undiscovered mechanism showing how caffeine can trigger the repair of heart muscles. The research, at this stage only involving mouse experiments, lends a newfound causal weight to the growing body of observational evidence suggesting caffeine has beneficial health effects.
Several recent large-scale observational studies have found that a moderate coffee intake may not only be safe, but also possibly beneficial to one's health. A massive umbrella study from 2017, collating data from 218 different meta-studies, concluded that coffee drinkers were 19 percent less likely to die from cardiovascular disease than non-coffee drinkers.
The problem with these observational studies is that, no matter how large the dataset, it's difficult to draw causal conclusions from the results. This new study, on the other hand, offers a vital clue that may help explain how coffee could confer protection against heart disease.
Prior research from the same German team established that caffeine improves the functional capacity of endothelial cells. These are important cells that line the inside of blood vessels, and when they become ineffective or dysfunctional it can lead to coronary heart disease, hypertension or diabetes.
This new study homes in further on the way caffeine affects these cells. It was discovered that caffeine induces the action of a protein called p27, which is responsible for promoting the migration of endothelial cells and boosting cell repair processes inside the heart.
"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," says Judith Haendeler, one of the lead researchers on the project.
The researchers tested the protective heart benefits of caffeine in several mouse models, including pre-diabetic, obese and aged animals, and found positive effects across the board. The study suggests the optimal caffeine concentration to achieve these specific beneficial effects equates to something close to four to five cups of coffee a day for humans.
Other scientists examining this new research urge caution in how we may interpret these results. Kevin McConway, from The Open University, suggests that as these results have only been shown in mouse models, they don't necessarily mean humans should suddenly drink more coffee to protect their hearts.
"Even if these processes work the same way in human bodies as in mouse bodies and cell cultures – and I think that might be a big if – it's still not clear whether drinking coffee by aging humans, such as me, will work in this way to protect our heart health," says McConway.
While this newfound causal link between caffeine and heart health certainly needs more study before anyone would seriously recommend you drink five cups of coffee a day for your health, the research does point to a promising mechanism that could be more directly pharmacologically modulated in the future.
"…enhancing mitochondrial p27 could serve as a potential therapeutic strategy not only in cardiovascular diseases but also in improving healthspan," suggests Haendeler.
The new research was published in the journal PLOS.
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