Coffee and the heart – four strong cups a day is beneficial finds study

By Dr. Ananya Mandal, MDJun 25 2018

According to a new study four cups of strong coffee might be the amount that would keep the hearts of older adults healthy. The latest study titled, “CDKN1B/p27 is localized in mitochondria and improves respiration-dependent processes in the cardiovascular system—New mode of action for caffeine,” was published on 21st of June 2018 in the journal PLOS Biology.

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The researchers from Germany led by Judith Haendeler and Joachim Altschmied who are molecular biologists looked at the effects of caffeine on the heart tissues in humans as well as in lab mice. Caffeine, a stimulant, they noted, had a beneficial effect on the blood vessel walls of older humans and made these walls more elastic and akin to the blood vessels of younger people. For this benefit to occur, the team noted that dosages close to four cups of coffee a day would be necessary.

There have been previous studies showing that coffee drinking can reduce the risk of deaths due to strokes, heart disease and diabetes. Two of these studies involved over 400,000 and over 500,000 Americans and Europeans respectively. The risk of dying due to heart disease is around 19 percent lowered with regular coffee intake, the studies had found. Coffee has also been found to reduce the risk of cirrhosis and liver disease and reduce the risk of cancers, dementia, depression and Alzheimer’s disease.

This new study looked at the molecular basis of such claims of beneficial effects of coffee. Obese and borderline diabetics benefit hugely from four cups of strong coffee per day, says Altschmied, as the study found. He added that healthy diet, regular physical exercise still are the cornerstones for reducing heart disease incidence, but coffee may be added to the daily routine to improve results. He added that green tea has same levels of caffeine as a cup of strong coffee and can be taken as an alternative.

The team found that there is a cell cycle inhibitor within the mitochondria of the cell called the cyclin-dependent kinase inhibitor 1B (CDKN1B)/p27. Presence of this mitochondrial p27 increases the ATP content. ATP is the energy packet of the cell. This mitochondrial p27 was found to prevent cell deaths in the heart tissues and their deficiency led to decrease in respiration in the heart tissue mitochondria. Introduction of caffeine in diet of the mice showed an improvement in respiration after a 10 day dosing, they noted. Caffeine was also found to reduce the size of the infarct or dead tissue caused due to lack of oxygen in the heart tissues in the mice by increasing mitochondrial p27.

Researchers warn that excessive coffee might not be a good idea. It could raise the heart rate and cause heart rhythm problems. This study, they write, was not performed on humans but on lab mice and human tissue only and that could be a limitation when extrapolating the theories on living humans. Altschmied also warned that since caffeine can widen the blood vessels and improve blood supply to different organs, it can also increase blood supply to the cancers and make them grow. For people with cancer, thus, too much coffee is not a good idea he said.