(ORDO NEWS) — Contrary to the fears of some doctors and the public, drinking coffee may actually protect your heart, not cause or worsen heart disease.
Drinking two to three cups of coffee daily is associated with a 10% to 15% lower risk of developing heart disease, heart failure, heart rhythm disturbances, or early death from any cause, three research abstracts published Thursday found.
“Because coffee can speed up the heart rate, some people worry that drinking it can trigger or exacerbate certain heart problems. This is where general medical advice to stop drinking coffee may come from,” Dr. Peter M. Kistler, senior author of the study, said in a statement.
Kistler is Head of Research in Clinical Electrophysiology at the Baker Heart and Diabetes Institute and Head of Electrophysiology at the Alfred Hospital in Melbourne, Australia.
“We found that drinking coffee either had a neutral effect – that is, no harm – or was associated with benefits for heart health,” said Kistler, a leading arrhythmia specialist, professor of medicine at the University of Melbourne and Monash University.
For all of the studies, Kistler and other researchers used data from the UK Biobank, which has been tracking the health of more than 500,000 people for at least 10 years.
When entering the register, participants reported in what range their coffee consumption was from one cup to six or more cups per day.
The authors of the current study wanted to investigate the association between coffee consumption and abnormal heart rhythms (arrhythmias), cardiovascular disease, including coronary heart disease, heart failure and stroke, and overall and heart related mortality among people with and without heart disease.
Coffee drinking and heart health
The first study included more than 382,500 adults without cardiovascular disease, with an average age of 57 years. Participants who drank two to three cups of coffee a day had the lowest risk of later developing the heart problems discussed in the study.
People who drank about one cup of coffee a day had the lowest risk of stroke or death from cardiovascular disease.
Another study examined the relationship between different types of coffee ground, instant, and decaffeinated and the same health outcomes. Kistler said in an email that it was not specified whether the decaffeinated coffee was ground or instant.
“Perhaps there is an opinion that less expensive instant coffee may be less useful than ground coffee, which is considered cleaner, but this was not the case in our study,” he added.
Drinking one to five cups of ground or instant coffee per day has been associated with a lower risk of arrhythmia, heart disease or failure, and stroke.
Drinking two to three cups of any type of coffee per day has been associated with a lower risk of early death or death from heart disease.
The participants in the third study were those who already suffered from arrhythmia or some type of cardiovascular disease.
In people with cardiovascular disease, no association was found between the level of coffee consumption and the development of arrhythmias. Among adults with arrhythmia, coffee consumption especially one cup a day has been associated with a lower risk of premature death.
“Clinicians are usually somewhat wary of people with known cardiovascular disease or arrhythmias who continue to drink coffee, so they are often cautious and advise them not to drink coffee altogether for fear that it may provoke dangerous heart rhythms.”
Kistler said in a statement. “But our study shows that regular coffee consumption is safe and may be part of a healthy diet for people with heart disease.”
Dr. David Cao, however, responded by email that he “does not believe there is enough information in this abstract to support this claim.”
Kao was not involved in the study and is an assistant professor in the departments of cardiology and bioinformatics and personalized medicine at Anschutz University of Colorado.
“It’s very important to understand what was adjusted in the analysis,” said Kao, who is also the medical director of the Colorado Center for Personalized Medicine.
The obvious one is age if young people, who have a lower risk of cardiovascular disease, drink the most coffee, then the apparent benefit of coffee may simply reflect the effect of age. “The authors do not mention what they were adjusting for, so you need to be careful.”
A press release for the analysis, however, says the researchers controlled for exercise, alcohol, smoking, diabetes and high blood pressure, as these factors can affect heart health and life expectancy. But the authors did not control for dietary factors.
“The problem is that the design of such studies will always be subject to what we call… selection bias people who end up drinking five cups of coffee a day may be drastically different from people who drink one cup a day or drink coffee.
decaffeinated,” said Dr. Lee Schwamm, vice president of digital and virtual patient care at Mass General Brigham in Boston. Some people experience negative effects after drinking coffee if they are more sensitive, while others drink espresso before bed and fall asleep immediately, he said.
The analysis “provides additional evidence that moderate coffee consumption does not increase the risk of heart disease and does not require cessation of consumption if a person has heart disease, even if it is an abnormal heart rhythm,” Kao said.
The results of the study will be presented at the 71st Annual Scientific Session of the American College of Cardiology on April 2-3.
What patients with heart disease should know
The study did not establish a causal relationship between coffee consumption and health status. But “there are a number of mechanisms by which coffee can reduce mortality and have beneficial effects on cardiovascular disease,” Kistler said in a press release.
It’s unclear whether caffeine is responsible for any of coffee’s health benefits, Kao said. “There are many biologically active compounds in coffee that may play a role,” he said.
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These compounds may help reduce inflammation, interfere with intestinal fat absorption, block receptors associated with abnormal heart rhythms, and reduce oxidative stress, Kistler says.
Oxidative stress is an imbalance between free radicals and antioxidants in the body. Free radicals are unstable molecules from environmental sources such as cigarette smoke or pesticides that can harm body cells.
If you’re unsure whether you can drink coffee based on your current or future risk of heart problems, talk to your doctor, says Schwamm, who is also a professor of neurology at Harvard Medical School.
“People should not take this as a statement that drinking coffee will increase their life expectancy,” he added.
“Certainly, the most important thing to prolong the life and quality of life of these patients will be a thoughtful plan with the doctor about physical activity, drugs to control cholesterol, blood pressure, blood sugar, smoking cessation (and more).”
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