- The researchers analyzed the amount and type of coffee consumption influences the risk of heart rhythm disturbances, cardiovascular disease and all-cause mortality among adults aged 40 to 69 years.
- They found that drinking 2-3 cups of coffee daily, whether instant, ground or decaffeinated, was associated with a lower risk of cardiovascular disease and death.
- Consuming caffeinated coffee, whether ground or straight away, was also associated with a lower risk of arrhythmias such as atrial fibrillation.
- The results suggest that mild to moderate coffee consumption of all types should be considered part of a healthy lifestyle and that people with heart disease do not necessarily have to give up coffee.
Good news for coffee drinkers was published earlier this year. Studies reported that drinking coffee is associated with a lower risk of mortality and that drinking coffee moderately every day can reduce the risk of kidney injury by 23%.
In the past, however, more than 75% of medical professionals have advised patients with cardiovascular diseases to avoid coffee. Recent observational studies have challenged this misconception by considering the safety and beneficial effects of caffeine consumption in relation to heart rhythm disorders disease.
information was available about the effects of different types of coffee on heart health. This prompted researchers from the Baker Heart and Diabetes Research Institute in Melbourne, Australia to conduct a large observational study that should provide some insights into the role of caffeine on cardiovascular outcomes by comparing the effects of decaffeinated and caffeinated coffee.
The newly published results suggest that instant coffee, ground and decaffeinated coffee, particularly at 2-3 cups per day, are associated with a lower risk of cardiovascular disease and death, and that caffeinated coffee significantly reduces the risk of heart rhythm disturbances.
Prof. Peter Kistler, Ph.D., author of the study and director of the Baker Heart and Diabetes Research Institute in Melbourne, Australia, explained:
“The real implications are that coffee should be considered part of a healthy diet. People should NOT stop drinking coffee if they develop any form of heart disease, including heart rhythm disturbances, unless they notice a specific personal connection between drinking coffee and their symptoms.
The study doesn’t show that if you have heart disease, you should start drinking coffee, but that if you’re already a coffee drinker, you should be sure it’s not only safe but also somewhat protective.”
The study was published in the European Journal of Preventive Cardiology.
Coffee and cardiovascular disease
Between January 1, 2006 and December 31, 2010, the study recruited participants from the British Biobank aged 40 to 69.
The study involved 449,563 participants who were not diagnosed with cardiovascular problems upon admission. The participants had an average age of 58 years and 55.3% were women.
The researchers asked participants to use a touchscreen questionnaire to report for themselves how many cups of coffee they drank each day and what type of coffee they normally drank. The different types of coffee were in order of popularity:
- instant coffee (44.1% of participants)
- ground coffee (18.4%)
- Decaffeinated coffee (15.2%)
22.4% of the study population did not drink coffee and served as a comparison group. For each type of coffee, the researchers divided study participants into 6 categories depending on their daily intake: 0.5 cups/day.
The researchers followed the health status of the participants for 12.5 years and determined their health results using ICD (International Classification of Diseases) codes in medical records and death certificates.
The study adjusted for factors that influence the risk of cardiovascular problems, including age, gender, alcohol consumption, tea consumption, obesity, diabetes, high blood pressure, obstructive sleep apnea, and smoking status. The researchers then found that people who usually drank ground, instant, or decaffeinated coffee had a significantly lower risk of cardiovascular disease and death from any reason than non-coffee drinkers.
The researchers observed that consuming 2-3 cups of coffee a day, regardless of the type of coffee, was consistently associated with the greatest risk reduction of cardiovascular disease, coronary heart disease, congestive heart failure, and death from any cause.
Caffeinated coffee lowers the risk of heart rhythm disturbances
An arrhythmia is when the heart beats too slowly, too fast, or irregularly. According to the Centers for Disease Control and Prevention (CDC), atrial fibrillation is the most common type of heart rhythm disorder treated.
The researchers found that ground coffee and instant coffee, but not decaffeinated coffee, were associated with a lower risk of arrhythmias, including atrial fibrillation. They saw a “U-shaped” relationship between caffeinated coffee intake and the risk of heart rhythm disturbances, with the lowest risk observed among those who consumed 2-3 cups of coffee daily.
“This study is new in identifying specific benefits of caffeinated coffee for atrial fibrillation that are biologically plausible given the effects of caffeine on adenosine receptors on heart cells,” Pro said. Kistler told MNT.
The heart must beat rhythmically to allow blood to circulate throughout the body. The time when the heart relaxes between beats is the refractory period. Adenosine produced by the body shortens the refractory period, which increases the risk of arrhythmias.
Previous studies have shown that caffeine blocks adenosine receptors and effectively protects the heart from the effects of adenosine. This antiarrhythmic property of caffeine could therefore explain the different effects of caffeinated and decaffeinated coffee on the risk of arrhythmia reported in this study.
Dr. Eric Topol, cardiologist, professor and founder and director of the Scripps Research Translational Institute, was impressed by the results of the new study on Twitter:
In their work, the researchers identified several study limitations that needed to be considered when interpreting their results. First, some participants had to be excluded from the analysis due to a lack of data.
Study participants’ coffee consumption was self-reported, which poses the potential risk of reporting biases. The participants were only able to select one type of coffee in the questionnaire, but some participants may have drunk more than one type of coffee daily. In addition, the researchers assumed that participants’ coffee consumption did not change from baseline to follow-up. However, it is possible that some participants may have drunk more than one type of coffee over time.
The researchers also acknowledged that the system for tracking participants’ health status (ICD-10 codes) is susceptible to measurement and reporting errors. In addition, certain arrhythmias, particularly atrial/ventricular ectopy, may have remained undetected.
The participants’ alcohol and tea consumption was taken into account in the analysis, but other components of the participants’ diet may have had an impact on their health outcomes.
Since most of the UK biobank population is Caucasian, the study conclusions may not fully apply to people from other ethnic groups.