Is decaf or regular coffee healthier for your heart?
Coffee, whether it’s caffeinated or not, may be good for the heart and may lead to a longer life if it’s consumed in moderation, a new study suggests.
An analysis of data from nearly 450,000 British adults revealed that the biggest health benefit was associated with drinking two to three cups of java per day. Caffeinated, but not decaffeinated, coffee was associated with a lower risk of irregular heart rhythms, according to the report published in the European Journal of Cardiology.
“People should think of coffee as a healthy part of their diet,” said study co-author Dr. Peter Kistler, head of clinical electrophysiology research at the Baker Heart and Diabetes Institute in Melbourne, Australia.
“They should not stop drinking coffee for health reasons unless they notice it directly causes symptoms, as some people are sensitive and can become anxious, tremulous or feel their heart rate increase with coffee,” Kistler said in an email. “All the data showing the benefits of coffee in heart disease are based on observational studies.”
These observational studies, Kistler noted, can’t prove that coffee is healthful because there could be other factors shared by coffee drinkers that make them healthier.
People might be surprised to hear that caffeinated coffee helps improve irregular heartbeats. But there is evidence that caffeine “can block receptors in the body that bind to adenosine,” Kistler said. “Adenosine is a molecule that can affect heart cells and increase the risk of arrhythmias. We believe by blocking these receptors which bind to adenosine, that caffeinated coffee may protect against arrhythmias.”
To take a closer look at the impact of various forms of coffee —caffeinated, decaffeinated, ground and instant — Kistler and his team turned to data from the UK Biobank study, which recruited adults between the ages of 40 and 69 who were willing to get regular physical exams and to provide lifestyle information. They were recruited between Jan. 1, 2006, and Dec. 31, 2010.
The researchers analyzed data from 449,563 biobank participants, who had a median age of 58 and 100,510 of whom didn’t drink coffee. The median follow-up period for the study was 12.5 years. Initially, no participants in the study had any form of heart disease, but by the end of follow-up, arrhythmia had been diagnosed in 30,100 (6.7%) and cardiovascular disease in 43,173 (9.6%), while 27,809 (6.2%) had died.
Kistler and his colleagues determined that consuming one to five cups of ground and/or instant caffeinated coffee daily was associated with a “significant” reduction in arrhythmia, the authors wrote. The lowest risk of arrhythmia came from drinking four to five cups of ground coffee daily or two to three cups of instant. As the number of cups consumed daily rose above five, the risk increased, known as a U-shaped curve.
All coffee types were associated with reduced risk of cardiovascular disease; drinking two to three cups of coffee per day — whether decaffeinated, instant and/or ground — had the lowest risk. All coffee types were also associated with a reduction in mortality from any cause, with two to three cups a day of decaffeinated, ground and instant having the greatest reduction.
The new study is well designed, prospective and large, said Dr. Samia Mora, director of the Center for Lipid Metabolomics at Brigham and Women’s Hospital.
“Like any observational study, there’s a potential for other factors that might explain the relationship we’re seeing,” Mora said. “It’s possible, for example, that the non-drinkers could be avoiding coffee because they were having symptoms, such as arrhythmia.”
Still, Mora said, coffee does contain a lot of compounds that are known to have health benefits, such as potassium, magnesium and niacin.
It’s unfortunate that the study didn’t break down coffee types further so that the researchers could have looked at the impact of coffee additives like sugar and cream, Mora said.
Coffee is listed as a part of the Mediterranean diet, “which has been shown in clinical trials to be associated with reductions in cardiovascular event and diabetes,” Mora said.
The new study “is not surprising,” said Dr. Chinmay Patel, a cardiologist specializing in electrophysiology at the University of Pittsburgh Medical Center Heart and Vascular Institute.
While it’s not a clinical trial, the study should still “be reassuring to patients who are moderate coffee drinkers,” Patel said. “But am I going to tell my patients they should be drinking four cups of coffee a day based on this study? No.”
This type of study is the best we’re going to get since no one is going to do a randomized clinical trial on coffee, Patel said. “More data is always welcome, and the findings are consistent with what’s been seen in the past,” he added.