One of the most commonly consumed beverages in the world, there’s long been debate over whether coffee is truly good for you. But the good news for coffee lovers everywhere is that a newly published study seems to add to the growing body of research supporting the benefits of coffee.
The study, which was published in the European Journal of Preventive Cardiology, suggests that two to three cups of coffee a day may actually protect you from developing heart disease and even early death.
"Decaffeinated, ground, and instant coffee, particularly at 2 to 3 cups/day, were associated with significant reductions in incident [cardiovascular disease] and mortality," researchers wrote. "Ground and instant but not decaffeinated coffee was associated with reduced arrhythmia."
With coffee being ubiquitous in most societies across the world and up to 80% of medical practitioners historically recommending that patients with cardiovascular disease avoid coffee, researchers for the current study wanted to examine whether that recommendation was really warranted.
Here's a closer look at what the study found and why coffee may actually help protect you from heart disease and increase longevity.
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The observational study analyzed data from patients who participated in the UK Biobank, which is a large-scale biomedical database and research resource that includes coffee consumption habits for nearly 450,000 adults. The patients included in the research effort were free of heart disease or arrhythmia at the start of the study and were divided into four groups: People who drank caffeinated ground coffee, people who drank decaf coffee, people who drank caffeinated instant coffee, and people who didn't drink coffee at all.
Researchers analyzed medical and death records for patients after an average of 12.5 years for issues such as arrhythmia, heart disease, stroke, and death. The researchers also adjusted for factors like age, diabetes, ethnicity, high blood pressure, obesity, obstructive sleep apnea, sex, smoking status, and tea and alcohol consumption.
As a result of their review, researchers found a variety of important benefits from coffee drinking including significant reductions in the risk for coronary heart disease, congestive heart failure and stroke when drinking ground, decaffeinated or caffeinated coffee. Ground coffee and instant coffee were also found to reduce risks for an irregular heartbeat, also known as arrhythmia.
"Our findings from the UK Biobank further corroborate the beneficial associations of habitual coffee intake as reported in recent population studies," the researchers wrote.
Study co-author Peter Kistler, Ph.D, head of clinical electrophysiology research at the Baker Heart and Diabetes Institute and head of electrophysiology at Alfred Hospital in Melbourne, told Health previous studies had linked coffee to a lowered risk of heart attacks, heart failure, and arrhythmias, but he said those efforts only involved a small number of participants and that the findings needed to be verified by a larger in a larger population, as his effort did.
"There is significant public interest in the cardiovascular benefits of coffee," Kistler said.
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Though this latest development may be good news for coffee lovers, the findings actually support previous studies that found drinking between three to five cups of black coffee a day can be beneficial for a variety of health conditions, including:
- Heart disease
- Alzheimer’s disease
- Parkinson’s disease
- Type 2 diabetes
- Liver disease
- Prostate cancer
“This is one of several studies that have come out in the last several years that seem to support moderate coffee consumption for health,” Holly Andersen, MD, attending cardiologist and an associate professor of clinical medicine at the New York-Presbyterian Hospital, Weill Cornell Medical Center, told Health.
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How Specifically Does Coffee Help Lower Risk of Death?
This study, like many others in the past, was observational, meaning it cannot pinpoint a specific cause and effect when it comes to how coffee helps lower risk of death. Randomized controlled trials would be needed to understand the relationship between coffee and cardiovascular health. However, there are some theories about what could be behind the link.
"Coffee is a complex drink which contains more than 100 biologically active compounds, of which caffeine is the most well known," Kistler said. "Caffeine is known to be a stimulant which increases alertness and concentration. However caffeine has other effects on the body such as reducing fat generation, and has antioxidant properties."
Caffeine also contains compounds called polyphenols which are known to be antioxidants, Kistler continued. "Polyphenols can also modify the body's metabolism, such as increasing the body's sensitivity to insulin, and improve the gut microbiome," he said. "All these effects are likely to explain the reductions in the risk of coronary heart disease, congestive heart failure, and stroke."
As for the arrhythmia risk, Kistler noted that caffeine can block receptors on cells in the body that bind to adenosine, a molecule that can affect heart cells and increase the risk of arrhythmias. "By blocking these receptors which bind to adenosine, we believe that caffeinated coffee may protect against arrhythmias," he said. "This may explain the differing effects" of caffeinated versus decaffeinated coffee when it comes to irregular heartbeat, he said.
But coffee in general—whether it’s caffeinated or not—is packed with “phytodiverse chemicals,” Rigved Tadwalkar, MD, a board certified cardiologist at Providence Saint John’s Health Center told Health. Meaning, there are a lot of different plant substances in coffee. “The sheer diversity and number of these compounds are likely the reason why all types of coffee are found to have benefits,” Dr. Tadwalkar said.
It’s also entirely possible that something else is at play here, Deborah Cohen, DCN, RDN, associate professor in the department of clinical and preventive nutrition sciences at Rutgers University, told Health. “Risk could be more related to body weight, diet composition, or physical activity vs coffee alone,” she said. “So many factors influence risk of death. It could be that those who drink a lot of coffee are more active, eat fewer calories and thus, are less overweight or obese which influence cardiovascular disease, type 2 diabetes risk, and more.”
How Much Does Coffee Reduce the Risk of Death?
The positive health impacts of coffee observed by the researchers were quite noticeable. People who drank two to three cups of coffee a day had the largest impact—among these individuals ground coffee led to a 27% lowered risk of death, while decaf drinkers had a 14% lower risk. The risk was 11% lower for those who drank instant caffeinated coffee.
When it comes to heart disease and stroke, the benefits among people who consumed three cups of coffee a day showed up as follows:
- Ground coffee: 20% lowered risk of heart disease and stroke
- Decaf coffee: 6% lowered risk of heart disease and stroke
- Instant: 9% lowered risk of heart disease and stroke
And finally, for irregular heartbeat the study showed:
- Individual who drink 4 to 5 cups of caffeinated ground coffee: 17% lowered risk
- Two to three cups a day of instant coffee: 12% lowered risk
Historically, caffeinated coffee has been viewed as a bad thing for patients with cardiovascular disease, but Kistler said that should begin change. "Mild–moderate coffee intake should not be discouraged but rather considered part of a healthy lifestyle," he said. And Kistler is not alone.
The latest findings "build on prior research that shows that coffee has, in my opinion, turned out to be this fairly magical substance," Dr. Tadwalker said.