Moderate caffeine consumption, primarily via coffee, is associated with lower risk for cardiovascular disease, including stroke, heart failure (HF), coronary artery disease (CAD), and hypertension. These findings were published in a scientific statement from the American Heart Association (AHA) in Circulation.
One of the most commonly consumed drugs worldwide is caffeine, primarily in beverages and food products. As such, disentangling the effects of caffeine from other food components is difficult. In addition, caffeine is known to affect multiple organs and to be metabolized differently depending on genetic and habitual use factors, all contributing to the ambiguity surrounding the effects of caffeine on health.
The effect of caffeine on blood pressure is poorly understood. Prospective cohort studies have reported an inverse J-shaped association between coffee consumption and hypertension risk, in which risk increased with 1 to 3 cups of coffee per day but tended to decrease with higher coffee consumption. Drinking an energy drink prior to exercise has been shown to increase submaximal systolic blood pressure, and using a caffeine-based supplement has been shown to attenuate exercise-induced reductions in blood pressure among young women.
Unfiltered coffee can increase serum cholesterol due to its cafestol content.
Potential health benefits that have been observed among individuals consuming caffeine that occurs in natural substances should not be extrapolated to synthetic products or high-dose caffeine.
Early epidemiologic studies reported a relationship between coffee consumption and CAD; however, recent prospective studies did not replicate these findings. On the contrary, a UK Biobank-based study found that consuming up to 5 cups of coffee per day decreased CAD risk compared with abstaining from coffee.
Similarly, early studies reported that consuming 5 or more cups of coffee per day increased risk for HF, but multiple modern cohort studies reported null relationships or lower risk for HF with coffee consumption.
In a dose-response meta-analysis, a U-shaped relationship between coffee consumption and stroke risk was reported, indicating that stroke risk was lowest with consumption of 3 to 4 cups of coffee per day. However, a UK Biobank-based study found that consumption of 4 or 5 or more cups of ground, instant, and decaffeinated coffee was associated with decreased risk for incident ischemic stroke.
Overall, the AHA statement concluded that moderate caffeine or coffee consumption, corresponding to 400 mg daily, or 3 to 5 cups of coffee, is safe for most adults and is associated with a lower risk for cardiovascular disease, including CAD, stroke, HF, and hypertension. This level of caffeine consumption is in line with the 2015 Dietary Guidelines Advisory Committee report.
The statement authors concluded, “Caffeine has heterogeneous effects that can meaningfully affect cardiovascular risk factors and cardiovascular diseases themselves….Many studies suggest potential protective effects, but these often come from studies of coffee as a beverage rather than caffeine per se in what are usually observational cohort studies….Potential health benefits that have been observed among individuals consuming caffeine that occurs in natural substances should not be extrapolated to synthetic products or high-dose caffeine. Indeed, although data on energy drinks are limited, available studies generally suggest cardiovascular harm.”
