Is coffee bad for the heart? New research links it to a major risk—and multiple benefits
Adults who drink a lot of coffee may face an increased heart attack risk, according to new meta-analysis published in BMC Cardiovascular Disorders.[1] On the other hand, high coffee intake was linked to a multiple benefits in the same study.
“At low doses, caffeine stimulates the central nervous system, resulting in diuresis, smooth muscle relaxation, cardiac/heart muscle stimulation and increased gastric secretion in adults,” wrote first author Eman E. Shaban, MBBCh, a researcher with the cardiology department at Al Jufairi Diagnosis and Treatment in Qatar, and colleagues. “Moreover, caffeine consumption has been recognized to have several positive effects on human health, including the prevention of type 2 diabetes mellitus, cardiovascular disease, cancer and Parkinson's disease. However, the mechanism behind these benefits is not clearly understood and is not believed to be related to caffeine since decaffeinated coffee also shows similar effects. On the other hand, high doses of caffeine have been shown to contribute to anxiety, nausea, and nervousness.”
With all of that context in mind, Shaban et al. hoped to provide an updated snapshot at the relationships between coffee intake and cardiovascular health. The group’s meta-analysis focused on 38 different studies involving more than 2.8 million patients.
Overall, researchers found that coffee consumption was not associated a patient’s risk of coronary heart disease or heart failure. Patients who drink a lot of coffee, however, were linked to a significantly higher risk of experiencing a myocardial infarction (MI).
“This positive association is biologically plausible, since high coffee consumption can activate the sympathetic nervous system, causing physiological changes such as increased heart rate, myocardial contractility, and oxygen demand, that can precipitate ischemic events in susceptible populations,” the authors wrote. “In addition, high coffee consumption has been associated with elevated levels of plasma homocysteine, which may further increase the risk of cardiovascular diseases such as MI. Nonetheless, inconsistencies across individual studies, including those reporting no significant associations even at high coffee consumption levels, highlight that the association between coffee consumption and MI is context-dependent, and might be influenced by baseline cardiovascular risk, lifestyle factors, genetic factors and coffee preparation method.”
The study’s authors also found that drinking coffee may reduce an adult’s risk of stroke or cardiac arrhythmia. Coffee has been previously linked to enhanced endothelial function and reduced levels of certain inflammation biomarkers, which helps explain the stoke benefit. The reduced arrhythmia risk, meanwhile, may be related to the fact that coffee drinkers develop a tolerance, “which diminishes the initial pro-arrhythmic properties of caffeine with time.”
“Moreover, coffee drinking has been associated with enhanced insulin sensitivity and a decreased incidence of type 2 diabetes, both of which are significant risk factors for atrial and ventricular arrhythmias,” the authors wrote. “The anti-inflammatory and antioxidant characteristics of coffee-derived polyphenols, including chlorogenic acid, may also aid in stabilizing cardiac electrophysiology.”
One final takeaway from the group’s research was the fact that a higher caffeine intake may be linked to a survival benefit for patients who present with hypertension. Society guidelines have previously recommended that hypertension patients consume less caffeine. However, as the authors explained, this finding implies “tailored guidance may be more suitable.”
Click here to read the full study.
Michael has more than 19 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.