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expert reaction to study looking at caffeine and heart cell health in mice and in cells

A new study, published in PLOS Biology, investigates the association between caffeine and protection of cardiovascular cells.


Dr Ian Johnson, Nutrition researcher and Emeritus Fellow, Quadram Institute Bioscience, said:

“This is an impressive piece of laboratory work describing a new and potentially beneficial effect of caffeine.  It might help to explain the protective effects of coffee consumption against heart disease which have been observed in some, but not all, studies on human populations, and this possibility deserves further investigation.  However, 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.”


Prof Tim Chico, Professor of Cardiovascular Medicine and Honorary Consultant Cardiologist, University of Sheffield, said:

“These researchers have discovered that a protein called p27 is important for recovery after heart attack in mice, and that p27 function is boosted by caffeine.  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.

“There is already some evidence suggesting coffee might protect against some diseases, which if true could be due to the effect of caffeine on p27.

“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).”


Prof Kevin McConway, Emeritus Professor of Applied Statistics, The Open University, said:

“It’s really important not to read too much into these results.  They are certainly interesting, but on their own they can’t go far in establishing whether or how coffee drinking might reduce risks to human health.

“It’s complicated to get to the bottom of whether a foodstuff or drink affects human health.  Several observational studies on people have found an association between drinking coffee and reduced risk of some diseases, including cardiovascular diseases such as heart attacks.  The snag is that it’s impossible to be sure whether the reduced risk is caused by the coffee drinking, or instead by some other factor that just happens to be associated with drinking coffee.  It’s not really feasible to do an experiment that makes some randomly chosen people drink several cups of coffee daily for decades, while others abstain from coffee even if some of them would normally have chosen to drink it.  So establishing what causes what usually involves finding out what might cause the protective effect, by looking at what goes on within the body’s cells.

“This new study contributes to that investigation by discovering how a particular molecule in the body could affect processes inside cells, and showing how that is affected by caffeine (as found in coffee).  This does make it a bit more plausible that drinking coffee could cause improvements in human health – but the new study was carried out in mice, and in cells in the laboratory which were mostly derived from mice (though some cells originating from human sources were involved).  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.

“I do like a nice cup of coffee, and I’d like to think it’s doing me a bit of good, but this study only goes a small way to persuading me that that’s actually true.”


* ‘CDKN1B/p27 is localized in mitochondria and improves respiration-dependent processes in the cardiovascular system – New mode of action for caffeine’ by Niloofar Ale-Agha et al.  published in PLOS Biology on Thursday 21 June 2018.


Declared interests

Dr Ian Johnson: “No conflicts of interest.”

Prof Kevin McConway: “Kevin McConway is a member of the Science Media Centre’s Advisory Committee.”

Prof Tim Chico: “No conflicts.”

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