New findings suggest that even heavy coffee drinkers may have nothing to worry about when it comes to cardiovascular health.
Does coffee harm, protect, or have no effect on heart health and the vascular system?
For years, scientists have been trying to answer these questions, since coffee is such a favorite beverage around the world.
While some studies warn that drinking coffee can increase a person's risk of cardiovascular events, others suggest that it can help maintain heart health and blood vessel function.
Some research has suggested that regularly drinking a lot of coffee contributes to aortic stiffness — this is when the aorta, which is the largest blood vessel in the human body, becomes less and less flexible. Aortic stiffness can contribute to the risk of cardiovascular disease.
At the same time, other evidence has indicated that drinking more than three cups of coffee a day can protect against atherosclerosis, a condition in which plaque builds up inside the arteries, preventing blood from flowing normally.
Now, a new study conducted by researchers from the Queen Mary University of London in the United Kingdom has found that even people who drink a significant amount of coffee each day do not experience arterial stiffness, meaning that coffee does not increase their risk of cardiovascular problems in this way.
Lead author Prof. Steffen Petersen and colleagues presented the study's findings yesterday at the annual British Cardiovascular Society (BCS) Conference in Manchester, U.K.
The British Heart Foundation, a registered charity based in the U.K. that supports research about heart and circulatory conditions, funded the study.
Same results across all groups
In the new study, the research team analyzed the data of 8,412 participants recruited via the U.K. Biobank Imaging Study. At the BCS Conference, the team explained that the participants agreed to undergo cardiovascular magnetic resonance imaging and other specialist assessments to allow the investigators to determine the state of their cardiovascular function.
The participants also self-reported how much coffee they typically drank on a day-to-day basis. Following these reports, the investigators then categorized the participants into three groups, according to their coffee consumption habits:people who drank one or fewer cups of coffee a day those who drank between one and three cups of coffee per day those who drank more than three cups of coffee per day
In their final analysis, Prof. Petersen and team excluded individuals who drank more than 25 cups of coffee per day, as well as those who had cardiovascular disease at baseline.
When comparing measurements of arterial stiffness between the three groups, the researchers found no differences between moderate and heavy coffee drinkers (those who drank between one and three or more than three cups of coffee per day, respectively) and those who had one cup off coffee or less per day.
These results, the investigators say, suggest that even drinking significant amounts of coffee is unlikely to have an ill effect on arterial health, so it may not negatively influence heart health and vascular function.
"Despite the huge popularity of coffee worldwide, different reports could put people off from enjoying it. Whilst we can't prove a causal link in this study, our research indicates coffee isn't as bad for the arteries as previous studies would suggest," explains study coauthor Kenneth Fung.
These findings remained in place after the investigators adjusted for possible factors contributing to arterial stiffness, including age, biological sex, ethnicity, smoking status, alcohol consumption, height, weight, eating habits, hypertension (high blood pressure), high cholesterol, and diabetes.
What should and what shouldn't we believe?
The researchers also noted that moderate and heavy coffee drinkers were more likely to be male, habitual smokers, and frequent drinkers of alcohol.
"Although our study included individuals who drink up to 25 cups a day, the average intake amongst the highest coffee consumption group was five cups a day. We would like to study these people more closely in our future work so that we can help to advise safe limits," Fung also specifies.
Prof. Metin Avkiran, who is Associate Medical Director at the British Heart Foundation, and who was not involved in the current research, explains that such studies about the relationship between coffee consumption habits and heart health can help individuals make better-informed decisions.
"Understanding the impact that coffee has on our heart and circulatory system is something that researchers and the media have had brewing for some time. There are several conflicting studies saying different things about coffee, and it can be difficult to filter what we should believe and what we shouldn't."
Prof. Metin Avkiran
"This research will hopefully put some of the media reports in perspective, as it rules out one of the potential detrimental effects of coffee on our arteries," Prof. Avkiran says.